mcs/mcs/cs-tokenizer.cs

   1 //
   2 // cs-tokenizer.cs: The Tokenizer for the C# compiler
   3 //                  This also implements the preprocessor
   4 //
   5 // Author: Miguel de Icaza (miguel@gnu.org)
   6 //         Marek Safar (marek.safar@gmail.com)
   7 //
   8 // Dual licensed under the terms of the MIT X11 or GNU GPL
   9 //
  10 // Copyright 2001, 2002 Ximian, Inc (http://www.ximian.com)
  11 // Copyright 2004-2008 Novell, Inc
  12 // Copyright 2011 Xamarin, Inc (http://www.xamarin.com)
  13 //
  14
  15 using System;
  16 using System.Text;
  17 using System.Collections.Generic;
  18 using System.Globalization;
  19 using System.Diagnostics;
  20 using System.Collections;
  21
  22 namespace Mono.CSharp
  23 {
  24         //
  25         // This class has to be used by parser only, it reuses token
  26         // details once a file is parsed
  27         //
  28         public class LocatedToken
  29         {
  30                 public int row, column;
  31                 public string value;
  32                 public SourceFile file;
  33
  34                 public LocatedToken ()
  35                 {
  36                 }
  37
  38                 public LocatedToken (string value, Location loc)
  39                 {
  40                         this.value = value;
  41                         file = loc.SourceFile;
  42                         row = loc.Row;
  43                         column = loc.Column;
  44                 }
  45
  46                 public override string ToString ()
  47                 {
  48                         return string.Format ("Token '{0}' at {1},{2}", Value, row, column);
  49                 }
  50
  51                 public Location Location
  52                 {
  53                         get { return new Location (file, row, column); }
  54                 }
  55
  56                 public string Value
  57                 {
  58                         get { return value; }
  59                 }
  60         }
  61
  62         /// <summary>
  63         ///    Tokenizer for C# source code.
  64         /// </summary>
  65         public class Tokenizer : yyParser.yyInput
  66         {
  67                 class KeywordEntry<T>
  68                 {
  69                         public readonly T Token;
  70                         public KeywordEntry<T> Next;
  71                         public readonly char[] Value;
  72
  73                         public KeywordEntry (string value, T token)
  74                         {
  75                                 this.Value = value.ToCharArray ();
  76                                 this.Token = token;
  77                         }
  78                 }
  79
  80                 sealed class IdentifiersComparer : IEqualityComparer<char[]>
  81                 {
  82                         readonly int length;
  83
  84                         public IdentifiersComparer (int length)
  85                         {
  86                                 this.length = length;
  87                         }
  88
  89                         public bool Equals (char[] x, char[] y)
  90                         {
  91                                 for (int i = 0; i < length; ++i)
  92                                         if (x [i] != y [i])
  93                                                 return false;
  94
  95                                 return true;
  96                         }
  97
  98                         public int GetHashCode (char[] obj)
  99                         {
 100                                 int h = 0;
 101                                 for (int i = 0; i < length; ++i)
 102                                         h = (h << 5) - h + obj [i];
 103
 104                                 return h;
 105                         }
 106                 }
 107
 108                 public class LocatedTokenBuffer
 109                 {
 110                         readonly LocatedToken[] buffer;
 111                         public int pos;
 112
 113                         public LocatedTokenBuffer ()
 114                         {
 115                                 buffer = new LocatedToken[0];
 116                         }
 117
 118                         public LocatedTokenBuffer (LocatedToken[] buffer)
 119                         {
 120                                 this.buffer = buffer ?? new LocatedToken[0];
 121                         }
 122
 123                         public LocatedToken Create (SourceFile file, int row, int column)
 124                         {
 125                                 return Create (null, file, row, column);
 126                         }
 127
 128                         public LocatedToken Create (string value, SourceFile file, int row, int column)
 129                         {
 130                                 //
 131                                 // TODO: I am not very happy about the logic but it's the best
 132                                 // what I could come up with for now.
 133                                 // Ideally we should be using just tiny buffer (256 elements) which
 134                                 // is enough to hold all details for currect stack and recycle elements
 135                                 // poped from the stack but there is a trick needed to recycle
 136                                 // them properly.
 137                                 //
 138                                 LocatedToken entry;
 139                                 if (pos >= buffer.Length) {
 140                                         entry = new LocatedToken ();
 141                                 } else {
 142                                         entry = buffer[pos];
 143                                         if (entry == null) {
 144                                                 entry = new LocatedToken ();
 145                                                 buffer[pos] = entry;
 146                                         }
 147
 148                                         ++pos;
 149                                 }
 150                                 entry.value = value;
 151                                 entry.file = file;
 152                                 entry.row = row;
 153                                 entry.column = column;
 154                                 return entry;
 155                         }
 156
 157                         //
 158                         // Used for token not required by expression evaluator
 159                         //
 160                         [Conditional ("FULL_AST")]
 161                         public void CreateOptional (SourceFile file, int row, int col, ref object token)
 162                         {
 163                                 token = Create (file, row, col);
 164                         }
 165                 }
 166
 167                 public enum PreprocessorDirective
 168                 {
 169                         Invalid = 0,
 170
 171                         Region = 1,
 172                         Endregion = 2,
 173                         If = 3 | RequiresArgument,
 174                         Endif = 4,
 175                         Elif = 5 | RequiresArgument,
 176                         Else = 6,
 177                         Define = 7 | RequiresArgument,
 178                         Undef = 8 | RequiresArgument,
 179                         Error = 9,
 180                         Warning = 10,
 181                         Pragma = 11 | CustomArgumentsParsing,
 182                         Line = 12 | CustomArgumentsParsing,
 183
 184                         CustomArgumentsParsing = 1 << 10,
 185                         RequiresArgument = 1 << 11
 186                 }
 187
 188                 readonly SeekableStreamReader reader;
 189                 readonly CompilationSourceFile source_file;
 190                 readonly CompilerContext context;
 191                 readonly Report Report;
 192
 193
 194                 SourceFile current_source;
 195                 Location hidden_block_start;
 196                 int ref_line = 1;
 197                 int line = 1;
 198                 int col = 0;
 199                 int previous_col;
 200                 int current_token;
 201                 readonly int tab_size;
 202                 bool handle_get_set = false;
 203                 bool handle_remove_add = false;
 204                 bool handle_where;
 205                 bool lambda_arguments_parsing;
 206                 List<Location> escaped_identifiers;
 207                 int parsing_generic_less_than;
 208                 readonly bool doc_processing;
 209                 readonly LocatedTokenBuffer ltb;
 210
 211                 //
 212                 // Used mainly for parser optimizations. Some expressions for instance
 213                 // can appear only in block (including initializer, base initializer)
 214                 // scope only
 215                 //
 216                 public int parsing_block;
 217                 internal bool query_parsing;
 218
 219                 //
 220                 // When parsing type only, useful for ambiguous nullable types
 221                 //
 222                 public int parsing_type;
 223
 224                 //
 225                 // Set when parsing generic declaration (type or method header)
 226                 //
 227                 public bool parsing_generic_declaration;
 228                 public bool parsing_generic_declaration_doc;
 229
 230                 //
 231                 // The value indicates that we have not reach any declaration or
 232                 // namespace yet
 233                 //
 234                 public int parsing_declaration;
 235
 236                 public bool parsing_attribute_section;
 237
 238                 public bool parsing_modifiers;
 239
 240                 //
 241                 // The special characters to inject on streams to run the unit parser
 242                 // in the special expression mode. Using private characters from
 243                 // Plane Sixteen (U+100000 to U+10FFFD)
 244                 //
 245                 // This character is only tested just before the tokenizer is about to report
 246                 // an error;   So on the regular operation mode, this addition will have no
 247                 // impact on the tokenizer's performance.
 248                 //
 249
 250                 public const int EvalStatementParserCharacter = 0x100000;
 251                 public const int EvalCompilationUnitParserCharacter = 0x100001;
 252                 public const int EvalUsingDeclarationsParserCharacter = 0x100002;
 253                 public const int DocumentationXref = 0x100003;
 254
 255                 const int UnicodeLS = 0x2028;
 256                 const int UnicodePS = 0x2029;
 257
 258                 //
 259                 // XML documentation buffer. The save point is used to divide
 260                 // comments on types and comments on members.
 261                 //
 262                 StringBuilder xml_comment_buffer;
 263
 264                 //
 265                 // See comment on XmlCommentState enumeration.
 266                 //
 267                 XmlCommentState xml_doc_state = XmlCommentState.Allowed;
 268
 269                 //
 270                 // Whether tokens have been seen on this line
 271                 //
 272                 bool tokens_seen = false;
 273
 274                 //
 275                 // Set to true once the GENERATE_COMPLETION token has bee
 276                 // returned.   This helps produce one GENERATE_COMPLETION,
 277                 // as many COMPLETE_COMPLETION as necessary to complete the
 278                 // AST tree and one final EOF.
 279                 //
 280                 bool generated;
 281
 282                 //
 283                 // Whether a token has been seen on the file
 284                 // This is needed because `define' is not allowed to be used
 285                 // after a token has been seen.
 286                 //
 287                 bool any_token_seen;
 288
 289                 //
 290                 // Class variables
 291                 //
 292                 static readonly KeywordEntry<int>[][] keywords;
 293                 static readonly KeywordEntry<PreprocessorDirective>[][] keywords_preprocessor;
 294                 static readonly HashSet<string> keyword_strings;
 295                 static readonly NumberStyles styles;
 296                 static readonly NumberFormatInfo csharp_format_info;
 297
 298                 // Pragma arguments
 299                 static readonly char[] pragma_warning = "warning".ToCharArray ();
 300                 static readonly char[] pragma_warning_disable = "disable".ToCharArray ();
 301                 static readonly char[] pragma_warning_restore = "restore".ToCharArray ();
 302                 static readonly char[] pragma_checksum = "checksum".ToCharArray ();
 303                 static readonly char[] line_hidden = "hidden".ToCharArray ();
 304                 static readonly char[] line_default = "default".ToCharArray ();
 305
 306                 static readonly char[] simple_whitespaces = new char[] { ' ', '\t' };
 307
 308                 public bool PropertyParsing {
 309                         get { return handle_get_set; }
 310                         set { handle_get_set = value; }
 311                 }
 312
 313                 public bool EventParsing {
 314                         get { return handle_remove_add; }
 315                         set { handle_remove_add = value; }
 316                 }
 317
 318                 public bool ConstraintsParsing {
 319                         get { return handle_where; }
 320                         set { handle_where = value; }
 321                 }
 322
 323                 public XmlCommentState doc_state {
 324                         get { return xml_doc_state; }
 325                         set {
 326                                 if (value == XmlCommentState.Allowed) {
 327                                         check_incorrect_doc_comment ();
 328                                         reset_doc_comment ();
 329                                 }
 330                                 xml_doc_state = value;
 331                         }
 332                 }
 333
 334                 //
 335                 // This is used to trigger completion generation on the parser
 336                 public bool CompleteOnEOF;
 337
 338                 void AddEscapedIdentifier (Location loc)
 339                 {
 340                         if (escaped_identifiers == null)
 341                                 escaped_identifiers = new List<Location> ();
 342
 343                         escaped_identifiers.Add (loc);
 344                 }
 345
 346                 public bool IsEscapedIdentifier (ATypeNameExpression name)
 347                 {
 348                         return escaped_identifiers != null && escaped_identifiers.Contains (name.Location);
 349                 }
 350
 351                 //
 352                 // Values for the associated token returned
 353                 //
 354                 internal int putback_char;      // Used by repl only
 355                 object val;
 356
 357                 //
 358                 // Pre-processor
 359                 //
 360                 const int TAKING        = 1;
 361                 const int ELSE_SEEN     = 4;
 362                 const int PARENT_TAKING = 8;
 363                 const int REGION        = 16;
 364
 365                 //
 366                 // pre-processor if stack state:
 367                 //
 368                 Stack<int> ifstack;
 369
 370                 public const int MaxIdentifierLength = 512;
 371                 public const int MaxNumberLength = 512;
 372
 373                 readonly char[] id_builder;
 374                 readonly Dictionary<char[], string>[] identifiers;
 375                 readonly char[] number_builder;
 376                 int number_pos;
 377
 378                 char[] value_builder = new char[64];
 379
 380                 public int Line {
 381                         get {
 382                                 return ref_line;
 383                         }
 384                 }
 385
 386                 //
 387                 // This is used when the tokenizer needs to save
 388                 // the current position as it needs to do some parsing
 389                 // on its own to deamiguate a token in behalf of the
 390                 // parser.
 391                 //
 392                 Stack<Position> position_stack = new Stack<Position> (2);
 393
 394                 class Position {
 395                         public int position;
 396                         public int line;
 397                         public int ref_line;
 398                         public int col;
 399                         public Location hidden;
 400                         public int putback_char;
 401                         public int previous_col;
 402                         public Stack<int> ifstack;
 403                         public int parsing_generic_less_than;
 404                         public int current_token;
 405                         public object val;
 406
 407                         public Position (Tokenizer t)
 408                         {
 409                                 position = t.reader.Position;
 410                                 line = t.line;
 411                                 ref_line = t.ref_line;
 412                                 col = t.col;
 413                                 hidden = t.hidden_block_start;
 414                                 putback_char = t.putback_char;
 415                                 previous_col = t.previous_col;
 416                                 if (t.ifstack != null && t.ifstack.Count != 0) {
 417                                         // There is no simple way to clone Stack<T> all
 418                                         // methods reverse the order
 419                                         var clone = t.ifstack.ToArray ();
 420                                         Array.Reverse (clone);
 421                                         ifstack = new Stack<int> (clone);
 422                                 }
 423                                 parsing_generic_less_than = t.parsing_generic_less_than;
 424                                 current_token = t.current_token;
 425                                 val = t.val;
 426                         }
 427                 }
 428
 429                 public Tokenizer (SeekableStreamReader input, CompilationSourceFile file, ParserSession session, Report report)
 430                 {
 431                         this.source_file = file;
 432                         this.context = file.Compiler;
 433                         this.current_source = file.SourceFile;
 434                         this.identifiers = session.Identifiers;
 435                         this.id_builder = session.IDBuilder;
 436                         this.number_builder = session.NumberBuilder;
 437                         this.ltb = new LocatedTokenBuffer (session.LocatedTokens);
 438                         this.Report = report;
 439
 440                         reader = input;
 441
 442                         putback_char = -1;
 443
 444                         xml_comment_buffer = new StringBuilder ();
 445                         doc_processing = context.Settings.DocumentationFile != null;
 446
 447                         tab_size = context.Settings.TabSize;
 448                 }
 449
 450                 public void PushPosition ()
 451                 {
 452                         position_stack.Push (new Position (this));
 453                 }
 454
 455                 public void PopPosition ()
 456                 {
 457                         Position p = position_stack.Pop ();
 458
 459                         reader.Position = p.position;
 460                         ref_line = p.ref_line;
 461                         line = p.line;
 462                         col = p.col;
 463                         hidden_block_start = p.hidden;
 464                         putback_char = p.putback_char;
 465                         previous_col = p.previous_col;
 466                         ifstack = p.ifstack;
 467                         parsing_generic_less_than = p.parsing_generic_less_than;
 468                         current_token = p.current_token;
 469                         val = p.val;
 470                 }
 471
 472                 // Do not reset the position, ignore it.
 473                 public void DiscardPosition ()
 474                 {
 475                         position_stack.Pop ();
 476                 }
 477
 478                 static void AddKeyword (string kw, int token)
 479                 {
 480                         keyword_strings.Add (kw);
 481
 482                         AddKeyword (keywords, kw, token);
 483                 }
 484
 485                 static void AddPreprocessorKeyword (string kw, PreprocessorDirective directive)
 486                 {
 487                         AddKeyword (keywords_preprocessor, kw, directive);
 488                 }
 489
 490                 static void AddKeyword<T> (KeywordEntry<T>[][] keywords, string kw, T token)
 491                 {
 492                         int length = kw.Length;
 493                         if (keywords[length] == null) {
 494                                 keywords[length] = new KeywordEntry<T>['z' - '_' + 1];
 495                         }
 496
 497                         int char_index = kw[0] - '_';
 498                         var kwe = keywords[length][char_index];
 499                         if (kwe == null) {
 500                                 keywords[length][char_index] = new KeywordEntry<T> (kw, token);
 501                                 return;
 502                         }
 503
 504                         while (kwe.Next != null) {
 505                                 kwe = kwe.Next;
 506                         }
 507
 508                         kwe.Next = new KeywordEntry<T> (kw, token);
 509                 }
 510
 511                 //
 512                 // Class initializer
 513                 //
 514                 static Tokenizer ()
 515                 {
 516                         keyword_strings = new HashSet<string> ();
 517
 518                         // 11 is the length of the longest keyword for now
 519                         keywords = new KeywordEntry<int>[11][];
 520
 521                         AddKeyword ("__arglist", Token.ARGLIST);
 522                         AddKeyword ("__makeref", Token.MAKEREF);
 523                         AddKeyword ("__reftype", Token.REFTYPE);
 524                         AddKeyword ("__refvalue", Token.REFVALUE);
 525                         AddKeyword ("abstract", Token.ABSTRACT);
 526                         AddKeyword ("as", Token.AS);
 527                         AddKeyword ("add", Token.ADD);
 528                         AddKeyword ("base", Token.BASE);
 529                         AddKeyword ("bool", Token.BOOL);
 530                         AddKeyword ("break", Token.BREAK);
 531                         AddKeyword ("byte", Token.BYTE);
 532                         AddKeyword ("case", Token.CASE);
 533                         AddKeyword ("catch", Token.CATCH);
 534                         AddKeyword ("char", Token.CHAR);
 535                         AddKeyword ("checked", Token.CHECKED);
 536                         AddKeyword ("class", Token.CLASS);
 537                         AddKeyword ("const", Token.CONST);
 538                         AddKeyword ("continue", Token.CONTINUE);
 539                         AddKeyword ("decimal", Token.DECIMAL);
 540                         AddKeyword ("default", Token.DEFAULT);
 541                         AddKeyword ("delegate", Token.DELEGATE);
 542                         AddKeyword ("do", Token.DO);
 543                         AddKeyword ("double", Token.DOUBLE);
 544                         AddKeyword ("else", Token.ELSE);
 545                         AddKeyword ("enum", Token.ENUM);
 546                         AddKeyword ("event", Token.EVENT);
 547                         AddKeyword ("explicit", Token.EXPLICIT);
 548                         AddKeyword ("extern", Token.EXTERN);
 549                         AddKeyword ("false", Token.FALSE);
 550                         AddKeyword ("finally", Token.FINALLY);
 551                         AddKeyword ("fixed", Token.FIXED);
 552                         AddKeyword ("float", Token.FLOAT);
 553                         AddKeyword ("for", Token.FOR);
 554                         AddKeyword ("foreach", Token.FOREACH);
 555                         AddKeyword ("goto", Token.GOTO);
 556                         AddKeyword ("get", Token.GET);
 557                         AddKeyword ("if", Token.IF);
 558                         AddKeyword ("implicit", Token.IMPLICIT);
 559                         AddKeyword ("in", Token.IN);
 560                         AddKeyword ("int", Token.INT);
 561                         AddKeyword ("interface", Token.INTERFACE);
 562                         AddKeyword ("internal", Token.INTERNAL);
 563                         AddKeyword ("is", Token.IS);
 564                         AddKeyword ("lock", Token.LOCK);
 565                         AddKeyword ("long", Token.LONG);
 566                         AddKeyword ("namespace", Token.NAMESPACE);
 567                         AddKeyword ("new", Token.NEW);
 568                         AddKeyword ("null", Token.NULL);
 569                         AddKeyword ("object", Token.OBJECT);
 570                         AddKeyword ("operator", Token.OPERATOR);
 571                         AddKeyword ("out", Token.OUT);
 572                         AddKeyword ("override", Token.OVERRIDE);
 573                         AddKeyword ("params", Token.PARAMS);
 574                         AddKeyword ("private", Token.PRIVATE);
 575                         AddKeyword ("protected", Token.PROTECTED);
 576                         AddKeyword ("public", Token.PUBLIC);
 577                         AddKeyword ("readonly", Token.READONLY);
 578                         AddKeyword ("ref", Token.REF);
 579                         AddKeyword ("remove", Token.REMOVE);
 580                         AddKeyword ("return", Token.RETURN);
 581                         AddKeyword ("sbyte", Token.SBYTE);
 582                         AddKeyword ("sealed", Token.SEALED);
 583                         AddKeyword ("set", Token.SET);
 584                         AddKeyword ("short", Token.SHORT);
 585                         AddKeyword ("sizeof", Token.SIZEOF);
 586                         AddKeyword ("stackalloc", Token.STACKALLOC);
 587                         AddKeyword ("static", Token.STATIC);
 588                         AddKeyword ("string", Token.STRING);
 589                         AddKeyword ("struct", Token.STRUCT);
 590                         AddKeyword ("switch", Token.SWITCH);
 591                         AddKeyword ("this", Token.THIS);
 592                         AddKeyword ("throw", Token.THROW);
 593                         AddKeyword ("true", Token.TRUE);
 594                         AddKeyword ("try", Token.TRY);
 595                         AddKeyword ("typeof", Token.TYPEOF);
 596                         AddKeyword ("uint", Token.UINT);
 597                         AddKeyword ("ulong", Token.ULONG);
 598                         AddKeyword ("unchecked", Token.UNCHECKED);
 599                         AddKeyword ("unsafe", Token.UNSAFE);
 600                         AddKeyword ("ushort", Token.USHORT);
 601                         AddKeyword ("using", Token.USING);
 602                         AddKeyword ("virtual", Token.VIRTUAL);
 603                         AddKeyword ("void", Token.VOID);
 604                         AddKeyword ("volatile", Token.VOLATILE);
 605                         AddKeyword ("while", Token.WHILE);
 606                         AddKeyword ("partial", Token.PARTIAL);
 607                         AddKeyword ("where", Token.WHERE);
 608
 609                         // LINQ keywords
 610                         AddKeyword ("from", Token.FROM);
 611                         AddKeyword ("join", Token.JOIN);
 612                         AddKeyword ("on", Token.ON);
 613                         AddKeyword ("equals", Token.EQUALS);
 614                         AddKeyword ("select", Token.SELECT);
 615                         AddKeyword ("group", Token.GROUP);
 616                         AddKeyword ("by", Token.BY);
 617                         AddKeyword ("let", Token.LET);
 618                         AddKeyword ("orderby", Token.ORDERBY);
 619                         AddKeyword ("ascending", Token.ASCENDING);
 620                         AddKeyword ("descending", Token.DESCENDING);
 621                         AddKeyword ("into", Token.INTO);
 622
 623                         // Contextual async keywords
 624                         AddKeyword ("async", Token.ASYNC);
 625                         AddKeyword ("await", Token.AWAIT);
 626
 627                         keywords_preprocessor = new KeywordEntry<PreprocessorDirective>[10][];
 628
 629                         AddPreprocessorKeyword ("region", PreprocessorDirective.Region);
 630                         AddPreprocessorKeyword ("endregion", PreprocessorDirective.Endregion);
 631                         AddPreprocessorKeyword ("if", PreprocessorDirective.If);
 632                         AddPreprocessorKeyword ("endif", PreprocessorDirective.Endif);
 633                         AddPreprocessorKeyword ("elif", PreprocessorDirective.Elif);
 634                         AddPreprocessorKeyword ("else", PreprocessorDirective.Else);
 635                         AddPreprocessorKeyword ("define", PreprocessorDirective.Define);
 636                         AddPreprocessorKeyword ("undef", PreprocessorDirective.Undef);
 637                         AddPreprocessorKeyword ("error", PreprocessorDirective.Error);
 638                         AddPreprocessorKeyword ("warning", PreprocessorDirective.Warning);
 639                         AddPreprocessorKeyword ("pragma", PreprocessorDirective.Pragma);
 640                         AddPreprocessorKeyword ("line", PreprocessorDirective.Line);
 641
 642                         csharp_format_info = NumberFormatInfo.InvariantInfo;
 643                         styles = NumberStyles.Float;
 644                 }
 645
 646                 int GetKeyword (char[] id, int id_len)
 647                 {
 648                         //
 649                         // Keywords are stored in an array of arrays grouped by their
 650                         // length and then by the first character
 651                         //
 652                         if (id_len >= keywords.Length || keywords [id_len] == null)
 653                                 return -1;
 654
 655                         int first_index = id [0] - '_';
 656                         if (first_index > 'z' - '_')
 657                                 return -1;
 658
 659                         var kwe = keywords [id_len] [first_index];
 660                         if (kwe == null)
 661                                 return -1;
 662
 663                         int res;
 664                         do {
 665                                 res = kwe.Token;
 666                                 for (int i = 1; i < id_len; ++i) {
 667                                         if (id [i] != kwe.Value [i]) {
 668                                                 res = 0;
 669                                                 kwe = kwe.Next;
 670                                                 break;
 671                                         }
 672                                 }
 673                         } while (res == 0 && kwe != null);
 674
 675                         if (res == 0)
 676                                 return -1;
 677
 678                         int next_token;
 679                         switch (res) {
 680                         case Token.GET:
 681                         case Token.SET:
 682                                 if (!handle_get_set)
 683                                         res = -1;
 684                                 break;
 685                         case Token.REMOVE:
 686                         case Token.ADD:
 687                                 if (!handle_remove_add)
 688                                         res = -1;
 689                                 break;
 690                         case Token.EXTERN:
 691                                 if (parsing_declaration == 0)
 692                                         res = Token.EXTERN_ALIAS;
 693                                 break;
 694                         case Token.DEFAULT:
 695                                 if (peek_token () == Token.COLON) {
 696                                         token ();
 697                                         res = Token.DEFAULT_COLON;
 698                                 }
 699                                 break;
 700                         case Token.WHERE:
 701                                 if (!(handle_where && current_token != Token.COLON) && !query_parsing)
 702                                         res = -1;
 703                                 break;
 704                         case Token.FROM:
 705                                 //
 706                                 // A query expression is any expression that starts with `from identifier'
 707                                 // followed by any token except ; , =
 708                                 //
 709                                 if (!query_parsing) {
 710                                         if (lambda_arguments_parsing || parsing_block == 0) {
 711                                                 res = -1;
 712                                                 break;
 713                                         }
 714
 715                                         PushPosition ();
 716                                         // HACK: to disable generics micro-parser, because PushPosition does not
 717                                         // store identifiers array
 718                                         parsing_generic_less_than = 1;
 719                                         switch (xtoken ()) {
 720                                         case Token.IDENTIFIER:
 721                                         case Token.INT:
 722                                         case Token.BOOL:
 723                                         case Token.BYTE:
 724                                         case Token.CHAR:
 725                                         case Token.DECIMAL:
 726                                         case Token.DOUBLE:
 727                                         case Token.FLOAT:
 728                                         case Token.LONG:
 729                                         case Token.OBJECT:
 730                                         case Token.STRING:
 731                                         case Token.UINT:
 732                                         case Token.ULONG:
 733                                                 next_token = xtoken ();
 734                                                 if (next_token == Token.SEMICOLON || next_token == Token.COMMA || next_token == Token.EQUALS || next_token == Token.ASSIGN)
 735                                                         goto default;
 736
 737                                                 res = Token.FROM_FIRST;
 738                                                 query_parsing = true;
 739                                                 if (context.Settings.Version <= LanguageVersion.ISO_2)
 740                                                         Report.FeatureIsNotAvailable (context, Location, "query expressions");
 741                                                 break;
 742                                         case Token.VOID:
 743                                                 Expression.Error_VoidInvalidInTheContext (Location, Report);
 744                                                 break;
 745                                         default:
 746                                                 PopPosition ();
 747                                                 // HACK: A token is not a keyword so we need to restore identifiers buffer
 748                                                 // which has been overwritten before we grabbed the identifier
 749                                                 id_builder [0] = 'f'; id_builder [1] = 'r'; id_builder [2] = 'o'; id_builder [3] = 'm';
 750                                                 return -1;
 751                                         }
 752                                         PopPosition ();
 753                                 }
 754                                 break;
 755                         case Token.JOIN:
 756                         case Token.ON:
 757                         case Token.EQUALS:
 758                         case Token.SELECT:
 759                         case Token.GROUP:
 760                         case Token.BY:
 761                         case Token.LET:
 762                         case Token.ORDERBY:
 763                         case Token.ASCENDING:
 764                         case Token.DESCENDING:
 765                         case Token.INTO:
 766                                 if (!query_parsing)
 767                                         res = -1;
 768                                 break;
 769
 770                         case Token.USING:
 771                         case Token.NAMESPACE:
 772                                 // TODO: some explanation needed
 773                                 check_incorrect_doc_comment ();
 774                                 parsing_modifiers = false;
 775                                 break;
 776
 777                         case Token.PARTIAL:
 778                                 if (parsing_block > 0) {
 779                                         res = -1;
 780                                         break;
 781                                 }
 782
 783                                 // Save current position and parse next token.
 784                                 PushPosition ();
 785
 786                                 next_token = token ();
 787                                 bool ok = (next_token == Token.CLASS) ||
 788                                         (next_token == Token.STRUCT) ||
 789                                         (next_token == Token.INTERFACE) ||
 790                                         (next_token == Token.VOID);
 791
 792                                 PopPosition ();
 793
 794                                 if (ok) {
 795                                         if (next_token == Token.VOID) {
 796                                                 if (context.Settings.Version <= LanguageVersion.ISO_2)
 797                                                         Report.FeatureIsNotAvailable (context, Location, "partial methods");
 798                                         } else if (context.Settings.Version == LanguageVersion.ISO_1)
 799                                                 Report.FeatureIsNotAvailable (context, Location, "partial types");
 800
 801                                         return res;
 802                                 }
 803
 804                                 if (next_token < Token.LAST_KEYWORD) {
 805                                         Report.Error (267, Location,
 806                                                 "The `partial' modifier can be used only immediately before `class', `struct', `interface', or `void' keyword");
 807                                         return token ();
 808                                 }
 809
 810                                 // HACK: A token is not a keyword so we need to restore identifiers buffer
 811                                 // which has been overwritten before we grabbed the identifier
 812                                 id_builder[0] = 'p';
 813                                 id_builder[1] = 'a';
 814                                 id_builder[2] = 'r';
 815                                 id_builder[3] = 't';
 816                                 id_builder[4] = 'i';
 817                                 id_builder[5] = 'a';
 818                                 id_builder[6] = 'l';
 819                                 res = -1;
 820                                 break;
 821
 822                         case Token.ASYNC:
 823                                 if (parsing_modifiers) {
 824                                         //
 825                                         // Skip attributes section or constructor called async
 826                                         //
 827                                         if (parsing_attribute_section || peek_token () == Token.OPEN_PARENS) {
 828                                                 res = -1;
 829                                         } else {
 830                                                 // async is keyword
 831                                         }
 832                                 } else if (parsing_block > 0) {
 833                                         switch (peek_token ()) {
 834                                         case Token.DELEGATE:
 835                                         case Token.OPEN_PARENS_LAMBDA:
 836                                                 // async is keyword
 837                                                 break;
 838                                         case Token.IDENTIFIER:
 839                                                 PushPosition ();
 840                                                 xtoken ();
 841                                                 if (xtoken () != Token.ARROW) {
 842                                                         PopPosition ();
 843                                                         goto default;
 844                                                 }
 845
 846                                                 PopPosition ();
 847                                                 break;
 848                                         default:
 849                                                 // peek_token could overwrite id_buffer
 850                                                 id_builder [0] = 'a'; id_builder [1] = 's'; id_builder [2] = 'y'; id_builder [3] = 'n'; id_builder [4] = 'c';
 851                                                 res = -1;
 852                                                 break;
 853                                         }
 854                                 } else {
 855                                         res = -1;
 856                                 }
 857
 858                                 if (res == Token.ASYNC && context.Settings.Version <= LanguageVersion.V_4) {
 859                                         Report.FeatureIsNotAvailable (context, Location, "asynchronous functions");
 860                                 }
 861
 862                                 break;
 863
 864                         case Token.AWAIT:
 865                                 if (parsing_block == 0)
 866                                         res = -1;
 867
 868                                 break;
 869                         }
 870
 871
 872                         return res;
 873                 }
 874
 875                 static PreprocessorDirective GetPreprocessorDirective (char[] id, int id_len)
 876                 {
 877                         //
 878                         // Keywords are stored in an array of arrays grouped by their
 879                         // length and then by the first character
 880                         //
 881                         if (id_len >= keywords_preprocessor.Length || keywords_preprocessor[id_len] == null)
 882                                 return PreprocessorDirective.Invalid;
 883
 884                         int first_index = id[0] - '_';
 885                         if (first_index > 'z' - '_')
 886                                 return PreprocessorDirective.Invalid;
 887
 888                         var kwe = keywords_preprocessor[id_len][first_index];
 889                         if (kwe == null)
 890                                 return PreprocessorDirective.Invalid;
 891
 892                         PreprocessorDirective res = PreprocessorDirective.Invalid;
 893                         do {
 894                                 res = kwe.Token;
 895                                 for (int i = 1; i < id_len; ++i) {
 896                                         if (id[i] != kwe.Value[i]) {
 897                                                 res = 0;
 898                                                 kwe = kwe.Next;
 899                                                 break;
 900                                         }
 901                                 }
 902                         } while (res == PreprocessorDirective.Invalid && kwe != null);
 903
 904                         return res;
 905                 }
 906
 907                 public Location Location {
 908                         get {
 909                                 return new Location (current_source, ref_line, col);
 910                         }
 911                 }
 912
 913                 static bool is_identifier_start_character (int c)
 914                 {
 915                         return (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || c == '_' || Char.IsLetter ((char)c);
 916                 }
 917
 918                 static bool is_identifier_part_character (char c)
 919                 {
 920                         if (c >= 'a' && c <= 'z')
 921                                 return true;
 922
 923                         if (c >= 'A' && c <= 'Z')
 924                                 return true;
 925
 926                         if (c == '_' || (c >= '0' && c <= '9'))
 927                                 return true;
 928
 929                         if (c < 0x80)
 930                                 return false;
 931
 932                         return is_identifier_part_character_slow_part (c);
 933                 }
 934
 935                 static bool is_identifier_part_character_slow_part (char c)
 936                 {
 937                         if (Char.IsLetter (c))
 938                                 return true;
 939
 940                         switch (Char.GetUnicodeCategory (c)) {
 941                                 case UnicodeCategory.ConnectorPunctuation:
 942
 943                                 // combining-character: A Unicode character of classes Mn or Mc
 944                                 case UnicodeCategory.NonSpacingMark:
 945                                 case UnicodeCategory.SpacingCombiningMark:
 946
 947                                 // decimal-digit-character: A Unicode character of the class Nd
 948                                 case UnicodeCategory.DecimalDigitNumber:
 949                                 return true;
 950                         }
 951
 952                         return false;
 953                 }
 954
 955                 public static bool IsKeyword (string s)
 956                 {
 957                         return keyword_strings.Contains (s);
 958                 }
 959
 960                 //
 961                 // Open parens micro parser. Detects both lambda and cast ambiguity.
 962                 //
 963                 int TokenizeOpenParens ()
 964                 {
 965                         int ptoken;
 966                         current_token = -1;
 967
 968                         int bracket_level = 0;
 969                         bool is_type = false;
 970                         bool can_be_type = false;
 971
 972                         while (true) {
 973                                 ptoken = current_token;
 974                                 token ();
 975
 976                                 switch (current_token) {
 977                                 case Token.CLOSE_PARENS:
 978                                         token ();
 979
 980                                         //
 981                                         // Expression inside parens is lambda, (int i) =>
 982                                         //
 983                                         if (current_token == Token.ARROW)
 984                                                 return Token.OPEN_PARENS_LAMBDA;
 985
 986                                         //
 987                                         // Expression inside parens is single type, (int[])
 988                                         //
 989                                         if (is_type) {
 990                                                 if (current_token == Token.SEMICOLON)
 991                                                         return Token.OPEN_PARENS;
 992
 993                                                 return Token.OPEN_PARENS_CAST;
 994                                         }
 995
 996                                         //
 997                                         // Expression is possible cast, look at next token, (T)null
 998                                         //
 999                                         if (can_be_type) {
1000                                                 switch (current_token) {
1001                                                 case Token.OPEN_PARENS:
1002                                                 case Token.BANG:
1003                                                 case Token.TILDE:
1004                                                 case Token.IDENTIFIER:
1005                                                 case Token.LITERAL:
1006                                                 case Token.BASE:
1007                                                 case Token.CHECKED:
1008                                                 case Token.DELEGATE:
1009                                                 case Token.FALSE:
1010                                                 case Token.FIXED:
1011                                                 case Token.NEW:
1012                                                 case Token.NULL:
1013                                                 case Token.SIZEOF:
1014                                                 case Token.THIS:
1015                                                 case Token.THROW:
1016                                                 case Token.TRUE:
1017                                                 case Token.TYPEOF:
1018                                                 case Token.UNCHECKED:
1019                                                 case Token.UNSAFE:
1020                                                 case Token.DEFAULT:
1021                                                 case Token.AWAIT:
1022
1023                                                 //
1024                                                 // These can be part of a member access
1025                                                 //
1026                                                 case Token.INT:
1027                                                 case Token.UINT:
1028                                                 case Token.SHORT:
1029                                                 case Token.USHORT:
1030                                                 case Token.LONG:
1031                                                 case Token.ULONG:
1032                                                 case Token.DOUBLE:
1033                                                 case Token.FLOAT:
1034                                                 case Token.CHAR:
1035                                                 case Token.BYTE:
1036                                                 case Token.DECIMAL:
1037                                                 case Token.BOOL:
1038                                                         return Token.OPEN_PARENS_CAST;
1039                                                 }
1040                                         }
1041                                         return Token.OPEN_PARENS;
1042
1043                                 case Token.DOT:
1044                                 case Token.DOUBLE_COLON:
1045                                         if (ptoken != Token.IDENTIFIER && ptoken != Token.OP_GENERICS_GT)
1046                                                 goto default;
1047
1048                                         continue;
1049
1050                                 case Token.IDENTIFIER:
1051                                 case Token.AWAIT:
1052                                         switch (ptoken) {
1053                                         case Token.DOT:
1054                                                 if (bracket_level == 0) {
1055                                                         is_type = false;
1056                                                         can_be_type = true;
1057                                                 }
1058
1059                                                 continue;
1060                                         case Token.OP_GENERICS_LT:
1061                                         case Token.COMMA:
1062                                         case Token.DOUBLE_COLON:
1063                                         case -1:
1064                                                 if (bracket_level == 0)
1065                                                         can_be_type = true;
1066                                                 continue;
1067                                         default:
1068                                                 can_be_type = is_type = false;
1069                                                 continue;
1070                                         }
1071
1072                                 case Token.OBJECT:
1073                                 case Token.STRING:
1074                                 case Token.BOOL:
1075                                 case Token.DECIMAL:
1076                                 case Token.FLOAT:
1077                                 case Token.DOUBLE:
1078                                 case Token.SBYTE:
1079                                 case Token.BYTE:
1080                                 case Token.SHORT:
1081                                 case Token.USHORT:
1082                                 case Token.INT:
1083                                 case Token.UINT:
1084                                 case Token.LONG:
1085                                 case Token.ULONG:
1086                                 case Token.CHAR:
1087                                 case Token.VOID:
1088                                         if (bracket_level == 0)
1089                                                 is_type = true;
1090                                         continue;
1091
1092                                 case Token.COMMA:
1093                                         if (bracket_level == 0) {
1094                                                 bracket_level = 100;
1095                                                 can_be_type = is_type = false;
1096                                         }
1097                                         continue;
1098
1099                                 case Token.OP_GENERICS_LT:
1100                                 case Token.OPEN_BRACKET:
1101                                         if (bracket_level++ == 0)
1102                                                 is_type = true;
1103                                         continue;
1104
1105                                 case Token.OP_GENERICS_GT:
1106                                 case Token.CLOSE_BRACKET:
1107                                         --bracket_level;
1108                                         continue;
1109
1110                                 case Token.INTERR_NULLABLE:
1111                                 case Token.STAR:
1112                                         if (bracket_level == 0)
1113                                                 is_type = true;
1114                                         continue;
1115
1116                                 case Token.REF:
1117                                 case Token.OUT:
1118                                         can_be_type = is_type = false;
1119                                         continue;
1120
1121                                 default:
1122                                         return Token.OPEN_PARENS;
1123                                 }
1124                         }
1125                 }
1126
1127                 public static bool IsValidIdentifier (string s)
1128                 {
1129                         if (s == null || s.Length == 0)
1130                                 return false;
1131
1132                         if (!is_identifier_start_character (s [0]))
1133                                 return false;
1134
1135                         for (int i = 1; i < s.Length; i ++)
1136                                 if (! is_identifier_part_character (s [i]))
1137                                         return false;
1138
1139                         return true;
1140                 }
1141
1142                 bool parse_less_than (ref int genericDimension)
1143                 {
1144                 start:
1145                         int the_token = token ();
1146                         if (the_token == Token.OPEN_BRACKET) {
1147                                 while (true) {
1148                                         the_token = token ();
1149                                         if (the_token == Token.EOF)
1150                                                 return true;
1151
1152                                         if (the_token == Token.CLOSE_BRACKET)
1153                                                 break;
1154                                 }
1155                                 the_token = token ();
1156                         } else if (the_token == Token.IN || the_token == Token.OUT) {
1157                                 the_token = token ();
1158                         }
1159                         switch (the_token) {
1160                         case Token.IDENTIFIER:
1161                         case Token.OBJECT:
1162                         case Token.STRING:
1163                         case Token.BOOL:
1164                         case Token.DECIMAL:
1165                         case Token.FLOAT:
1166                         case Token.DOUBLE:
1167                         case Token.SBYTE:
1168                         case Token.BYTE:
1169                         case Token.SHORT:
1170                         case Token.USHORT:
1171                         case Token.INT:
1172                         case Token.UINT:
1173                         case Token.LONG:
1174                         case Token.ULONG:
1175                         case Token.CHAR:
1176                         case Token.VOID:
1177                                 break;
1178                         case Token.OP_GENERICS_GT:
1179                                 genericDimension = 1;
1180                                 return true;
1181                         case Token.IN:
1182                         case Token.OUT:
1183                                 return true;
1184                         case Token.COMMA:
1185                                 do {
1186                                         ++genericDimension;
1187                                         the_token = token ();
1188                                 } while (the_token == Token.COMMA);
1189
1190                                 if (the_token == Token.OP_GENERICS_GT) {
1191                                         ++genericDimension;
1192                                         return true;
1193                                 }
1194
1195                                 return false;
1196                         default:
1197                                 return false;
1198                         }
1199                 again:
1200                         the_token = token ();
1201
1202                         if (the_token == Token.OP_GENERICS_GT)
1203                                 return true;
1204                         else if (the_token == Token.COMMA || the_token == Token.DOT || the_token == Token.DOUBLE_COLON)
1205                                 goto start;
1206                         else if (the_token == Token.INTERR_NULLABLE || the_token == Token.STAR)
1207                                 goto again;
1208                         else if (the_token == Token.OP_GENERICS_LT) {
1209                                 if (!parse_less_than (ref genericDimension))
1210                                         return false;
1211                                 goto again;
1212                         } else if (the_token == Token.OPEN_BRACKET) {
1213                         rank_specifiers:
1214                                 the_token = token ();
1215                                 if (the_token == Token.CLOSE_BRACKET)
1216                                         goto again;
1217                                 else if (the_token == Token.COMMA)
1218                                         goto rank_specifiers;
1219                                 return false;
1220                         }
1221
1222                         return false;
1223                 }
1224
1225                 public int peek_token ()
1226                 {
1227                         int the_token;
1228
1229                         PushPosition ();
1230                         the_token = token ();
1231                         PopPosition ();
1232
1233                         return the_token;
1234                 }
1235
1236                 //
1237                 // Tonizes `?' using custom disambiguous rules to return one
1238                 // of following tokens: INTERR_NULLABLE, OP_COALESCING, INTERR
1239                 //
1240                 // Tricky expression looks like:
1241                 //
1242                 // Foo ? a = x ? b : c;
1243                 //
1244                 int TokenizePossibleNullableType ()
1245                 {
1246                         if (parsing_block == 0 || parsing_type > 0)
1247                                 return Token.INTERR_NULLABLE;
1248
1249                         int d = peek_char ();
1250                         if (d == '?') {
1251                                 get_char ();
1252                                 return Token.OP_COALESCING;
1253                         }
1254
1255                         if (d == '.') {
1256                                 return Token.INTERR_OPERATOR;
1257                         }
1258
1259                         if (d != ' ') {
1260                                 if (d == ',' || d == ';' || d == '>')
1261                                         return Token.INTERR_NULLABLE;
1262                                 if (d == '*' || (d >= '0' && d <= '9'))
1263                                         return Token.INTERR;
1264                         }
1265
1266                         PushPosition ();
1267                         current_token = Token.NONE;
1268                         int next_token;
1269                         int parens = 0;
1270                         int generics = 0;
1271
1272                         var nt = xtoken ();
1273                         switch (nt) {
1274                         case Token.DOT:
1275                         case Token.OPEN_BRACKET_EXPR:
1276                                 next_token = Token.INTERR_OPERATOR;
1277                                 break;
1278                         case Token.LITERAL:
1279                         case Token.TRUE:
1280                         case Token.FALSE:
1281                         case Token.NULL:
1282                         case Token.THIS:
1283                         case Token.NEW:
1284                                 next_token = Token.INTERR;
1285                                 break;
1286
1287                         case Token.SEMICOLON:
1288                         case Token.COMMA:
1289                         case Token.CLOSE_PARENS:
1290                         case Token.OPEN_BRACKET:
1291                         case Token.OP_GENERICS_GT:
1292                         case Token.INTERR:
1293                         case Token.OP_COALESCING:
1294                         case Token.COLON:
1295                                 next_token = Token.INTERR_NULLABLE;
1296                                 break;
1297
1298                         case Token.OPEN_PARENS:
1299                         case Token.OPEN_PARENS_CAST:
1300                         case Token.OPEN_PARENS_LAMBDA:
1301                                 next_token = -1;
1302                                 ++parens;
1303                                 break;
1304
1305                         case Token.OP_GENERICS_LT:
1306                         case Token.OP_GENERICS_LT_DECL:
1307                         case Token.GENERIC_DIMENSION:
1308                                 next_token = -1;
1309                                 ++generics;
1310                                 break;
1311
1312                         default:
1313                                 next_token = -1;
1314                                 break;
1315                         }
1316
1317                         if (next_token == -1) {
1318                                 switch (xtoken ()) {
1319                                 case Token.COMMA:
1320                                 case Token.SEMICOLON:
1321                                 case Token.OPEN_BRACE:
1322                                 case Token.CLOSE_PARENS:
1323                                 case Token.IN:
1324                                         next_token = Token.INTERR_NULLABLE;
1325                                         break;
1326
1327                                 case Token.COLON:
1328                                         next_token = Token.INTERR;
1329                                         break;
1330
1331                                 case Token.OPEN_PARENS:
1332                                 case Token.OPEN_PARENS_CAST:
1333                                 case Token.OPEN_PARENS_LAMBDA:
1334                                         ++parens;
1335                                         goto default;
1336
1337                                 case Token.OP_GENERICS_LT:
1338                                 case Token.OP_GENERICS_LT_DECL:
1339                                 case Token.GENERIC_DIMENSION:
1340                                         ++generics;
1341                                         goto default;
1342
1343                                 default:
1344                                         int ntoken;
1345                                         int interrs = 1;
1346                                         int colons = 0;
1347                                         int braces = 0;
1348                                         int brackets = 0;
1349                                         //
1350                                         // All shorcuts failed, do it hard way
1351                                         //
1352                                         while ((ntoken = xtoken ()) != Token.EOF) {
1353                                                 switch (ntoken) {
1354                                                 case Token.OPEN_BRACE:
1355                                                         ++braces;
1356                                                         continue;
1357                                                 case Token.OPEN_PARENS:
1358                                                 case Token.OPEN_PARENS_CAST:
1359                                                 case Token.OPEN_PARENS_LAMBDA:
1360                                                         ++parens;
1361                                                         continue;
1362                                                 case Token.CLOSE_BRACE:
1363                                                         --braces;
1364                                                         continue;
1365                                                 case Token.OP_GENERICS_LT:
1366                                                 case Token.OP_GENERICS_LT_DECL:
1367                                                 case Token.GENERIC_DIMENSION:
1368                                                         ++generics;
1369                                                         continue;
1370                                                 case Token.OPEN_BRACKET:
1371                                                 case Token.OPEN_BRACKET_EXPR:
1372                                                         ++brackets;
1373                                                         continue;
1374                                                 case Token.CLOSE_BRACKET:
1375                                                         --brackets;
1376                                                         continue;
1377                                                 case Token.CLOSE_PARENS:
1378                                                         if (parens > 0) {
1379                                                                 --parens;
1380                                                                 continue;
1381                                                         }
1382
1383                                                         PopPosition ();
1384                                                         return Token.INTERR_NULLABLE;
1385
1386                                                 case Token.OP_GENERICS_GT:
1387                                                         if (generics > 0) {
1388                                                                 --generics;
1389                                                                 continue;
1390                                                         }
1391
1392                                                         PopPosition ();
1393                                                         return Token.INTERR_NULLABLE;
1394                                                 }
1395
1396                                                 if (braces != 0)
1397                                                         continue;
1398
1399                                                 if (ntoken == Token.SEMICOLON)
1400                                                         break;
1401
1402                                                 if (parens != 0)
1403                                                         continue;
1404
1405                                                 if (ntoken == Token.COMMA) {
1406                                                         if (generics != 0 || brackets != 0)
1407                                                                 continue;
1408
1409                                                         PopPosition ();
1410                                                         return Token.INTERR_NULLABLE;
1411                                                 }
1412
1413                                                 if (ntoken == Token.COLON) {
1414                                                         if (++colons == interrs)
1415                                                                 break;
1416                                                         continue;
1417                                                 }
1418
1419                                                 if (ntoken == Token.INTERR) {
1420                                                         ++interrs;
1421                                                         continue;
1422                                                 }
1423                                         }
1424
1425                                         next_token = colons != interrs && braces == 0 ? Token.INTERR_NULLABLE : Token.INTERR;
1426                                         break;
1427                                 }
1428                         }
1429
1430                         PopPosition ();
1431                         return next_token;
1432                 }
1433
1434                 bool decimal_digits (int c)
1435                 {
1436                         int d;
1437                         bool seen_digits = false;
1438
1439                         if (c != -1){
1440                                 if (number_pos == MaxNumberLength)
1441                                         Error_NumericConstantTooLong ();
1442                                 number_builder [number_pos++] = (char) c;
1443                         }
1444
1445                         //
1446                         // We use peek_char2, because decimal_digits needs to do a
1447                         // 2-character look-ahead (5.ToString for example).
1448                         //
1449                         while ((d = peek_char2 ()) != -1){
1450                                 if (d >= '0' && d <= '9'){
1451                                         if (number_pos == MaxNumberLength)
1452                                                 Error_NumericConstantTooLong ();
1453                                         number_builder [number_pos++] = (char) d;
1454                                         get_char ();
1455                                         seen_digits = true;
1456                                 } else
1457                                         break;
1458                         }
1459
1460                         return seen_digits;
1461                 }
1462
1463                 static bool is_hex (int e)
1464                 {
1465                         return (e >= '0' && e <= '9') || (e >= 'A' && e <= 'F') || (e >= 'a' && e <= 'f');
1466                 }
1467
1468                 static TypeCode real_type_suffix (int c)
1469                 {
1470                         switch (c){
1471                         case 'F': case 'f':
1472                                 return TypeCode.Single;
1473                         case 'D': case 'd':
1474                                 return TypeCode.Double;
1475                         case 'M': case 'm':
1476                                 return TypeCode.Decimal;
1477                         default:
1478                                 return TypeCode.Empty;
1479                         }
1480                 }
1481
1482                 ILiteralConstant integer_type_suffix (ulong ul, int c, Location loc)
1483                 {
1484                         bool is_unsigned = false;
1485                         bool is_long = false;
1486
1487                         if (c != -1){
1488                                 bool scanning = true;
1489                                 do {
1490                                         switch (c){
1491                                         case 'U': case 'u':
1492                                                 if (is_unsigned)
1493                                                         scanning = false;
1494                                                 is_unsigned = true;
1495                                                 get_char ();
1496                                                 break;
1497
1498                                         case 'l':
1499                                                 if (!is_unsigned){
1500                                                         //
1501                                                         // if we have not seen anything in between
1502                                                         // report this error
1503                                                         //
1504                                                         Report.Warning (78, 4, Location, "The `l' suffix is easily confused with the digit `1' (use `L' for clarity)");
1505                                                 }
1506
1507                                                 goto case 'L';
1508
1509                                         case 'L':
1510                                                 if (is_long)
1511                                                         scanning = false;
1512                                                 is_long = true;
1513                                                 get_char ();
1514                                                 break;
1515
1516                                         default:
1517                                                 scanning = false;
1518                                                 break;
1519                                         }
1520                                         c = peek_char ();
1521                                 } while (scanning);
1522                         }
1523
1524                         if (is_long && is_unsigned){
1525                                 return new ULongLiteral (context.BuiltinTypes, ul, loc);
1526                         }
1527
1528                         if (is_unsigned){
1529                                 // uint if possible, or ulong else.
1530
1531                                 if ((ul & 0xffffffff00000000) == 0)
1532                                         return new UIntLiteral (context.BuiltinTypes, (uint) ul, loc);
1533                                 else
1534                                         return new ULongLiteral (context.BuiltinTypes, ul, loc);
1535                         } else if (is_long){
1536                                 // long if possible, ulong otherwise
1537                                 if ((ul & 0x8000000000000000) != 0)
1538                                         return new ULongLiteral (context.BuiltinTypes, ul, loc);
1539                                 else
1540                                         return new LongLiteral (context.BuiltinTypes, (long) ul, loc);
1541                         } else {
1542                                 // int, uint, long or ulong in that order
1543                                 if ((ul & 0xffffffff00000000) == 0){
1544                                         uint ui = (uint) ul;
1545
1546                                         if ((ui & 0x80000000) != 0)
1547                                                 return new UIntLiteral (context.BuiltinTypes, ui, loc);
1548                                         else
1549                                                 return new IntLiteral (context.BuiltinTypes, (int) ui, loc);
1550                                 } else {
1551                                         if ((ul & 0x8000000000000000) != 0)
1552                                                 return new ULongLiteral (context.BuiltinTypes, ul, loc);
1553                                         else
1554                                                 return new LongLiteral (context.BuiltinTypes, (long) ul, loc);
1555                                 }
1556                         }
1557                 }
1558
1559                 //
1560                 // given `c' as the next char in the input decide whether
1561                 // we need to convert to a special type, and then choose
1562                 // the best representation for the integer
1563                 //
1564                 ILiteralConstant adjust_int (int c, Location loc)
1565                 {
1566                         try {
1567                                 if (number_pos > 9){
1568                                         ulong ul = (uint) (number_builder [0] - '0');
1569
1570                                         for (int i = 1; i < number_pos; i++){
1571                                                 ul = checked ((ul * 10) + ((uint)(number_builder [i] - '0')));
1572                                         }
1573
1574                                         return integer_type_suffix (ul, c, loc);
1575                                 } else {
1576                                         uint ui = (uint) (number_builder [0] - '0');
1577
1578                                         for (int i = 1; i < number_pos; i++){
1579                                                 ui = checked ((ui * 10) + ((uint)(number_builder [i] - '0')));
1580                                         }
1581
1582                                         return integer_type_suffix (ui, c, loc);
1583                                 }
1584                         } catch (OverflowException) {
1585                                 Error_NumericConstantTooLong ();
1586                                 return new IntLiteral (context.BuiltinTypes, 0, loc);
1587                         }
1588                         catch (FormatException) {
1589                                 Report.Error (1013, Location, "Invalid number");
1590                                 return new IntLiteral (context.BuiltinTypes, 0, loc);
1591                         }
1592                 }
1593
1594                 ILiteralConstant adjust_real (TypeCode t, Location loc)
1595                 {
1596                         string s = new string (number_builder, 0, number_pos);
1597                         const string error_details = "Floating-point constant is outside the range of type `{0}'";
1598
1599                         switch (t){
1600                         case TypeCode.Decimal:
1601                                 try {
1602                                         return new DecimalLiteral (context.BuiltinTypes, decimal.Parse (s, styles, csharp_format_info), loc);
1603                                 } catch (OverflowException) {
1604                                         Report.Error (594, Location, error_details, "decimal");
1605                                         return new DecimalLiteral (context.BuiltinTypes, 0, loc);
1606                                 }
1607                         case TypeCode.Single:
1608                                 try {
1609                                         return new FloatLiteral (context.BuiltinTypes, float.Parse (s, styles, csharp_format_info), loc);
1610                                 } catch (OverflowException) {
1611                                         Report.Error (594, Location, error_details, "float");
1612                                         return new FloatLiteral (context.BuiltinTypes, 0, loc);
1613                                 }
1614                         default:
1615                                 try {
1616                                         return new DoubleLiteral (context.BuiltinTypes, double.Parse (s, styles, csharp_format_info), loc);
1617                                 } catch (OverflowException) {
1618                                         Report.Error (594, loc, error_details, "double");
1619                                         return new DoubleLiteral (context.BuiltinTypes, 0, loc);
1620                                 }
1621                         }
1622                 }
1623
1624                 ILiteralConstant handle_hex (Location loc)
1625                 {
1626                         int d;
1627                         ulong ul;
1628
1629                         get_char ();
1630                         while ((d = peek_char ()) != -1){
1631                                 if (is_hex (d)){
1632                                         number_builder [number_pos++] = (char) d;
1633                                         get_char ();
1634                                 } else
1635                                         break;
1636                         }
1637
1638                         string s = new String (number_builder, 0, number_pos);
1639
1640                         try {
1641                                 if (number_pos <= 8)
1642                                         ul = System.UInt32.Parse (s, NumberStyles.HexNumber);
1643                                 else
1644                                         ul = System.UInt64.Parse (s, NumberStyles.HexNumber);
1645
1646                                 return integer_type_suffix (ul, peek_char (), loc);
1647                         } catch (OverflowException){
1648                                 Error_NumericConstantTooLong ();
1649                                 return new IntLiteral (context.BuiltinTypes, 0, loc);
1650                         }
1651                         catch (FormatException) {
1652                                 Report.Error (1013, Location, "Invalid number");
1653                                 return new IntLiteral (context.BuiltinTypes, 0, loc);
1654                         }
1655                 }
1656
1657                 //
1658                 // Invoked if we know we have .digits or digits
1659                 //
1660                 int is_number (int c, bool dotLead)
1661                 {
1662                         ILiteralConstant res;
1663
1664 #if FULL_AST
1665                         int read_start = reader.Position - 1;
1666                         if (dotLead) {
1667                                 //
1668                                 // Caller did peek_char
1669                                 //
1670                                 --read_start;
1671                         }
1672 #endif
1673                         number_pos = 0;
1674                         var loc = Location;
1675
1676                         if (!dotLead){
1677                                 if (c == '0'){
1678                                         int peek = peek_char ();
1679
1680                                         if (peek == 'x' || peek == 'X') {
1681                                                 val = res = handle_hex (loc);
1682 #if FULL_AST
1683                                                 res.ParsedValue = reader.ReadChars (read_start, reader.Position - 1);
1684 #endif
1685
1686                                                 return Token.LITERAL;
1687                                         }
1688                                 }
1689                                 decimal_digits (c);
1690                                 c = peek_char ();
1691                         }
1692
1693                         //
1694                         // We need to handle the case of
1695                         // "1.1" vs "1.string" (LITERAL_FLOAT vs NUMBER DOT IDENTIFIER)
1696                         //
1697                         bool is_real = false;
1698                         if (c == '.'){
1699                                 if (!dotLead)
1700                                         get_char ();
1701
1702                                 if (decimal_digits ('.')){
1703                                         is_real = true;
1704                                         c = peek_char ();
1705                                 } else {
1706                                         putback ('.');
1707                                         number_pos--;
1708                                         val = res = adjust_int (-1, loc);
1709
1710 #if FULL_AST
1711                                         res.ParsedValue = reader.ReadChars (read_start, reader.Position - 1);
1712 #endif
1713                                         return Token.LITERAL;
1714                                 }
1715                         }
1716
1717                         if (c == 'e' || c == 'E'){
1718                                 is_real = true;
1719                                 get_char ();
1720                                 if (number_pos == MaxNumberLength)
1721                                         Error_NumericConstantTooLong ();
1722                                 number_builder [number_pos++] = (char) c;
1723                                 c = get_char ();
1724
1725                                 if (c == '+'){
1726                                         if (number_pos == MaxNumberLength)
1727                                                 Error_NumericConstantTooLong ();
1728                                         number_builder [number_pos++] = '+';
1729                                         c = -1;
1730                                 } else if (c == '-') {
1731                                         if (number_pos == MaxNumberLength)
1732                                                 Error_NumericConstantTooLong ();
1733                                         number_builder [number_pos++] = '-';
1734                                         c = -1;
1735                                 } else {
1736                                         if (number_pos == MaxNumberLength)
1737                                                 Error_NumericConstantTooLong ();
1738                                         number_builder [number_pos++] = '+';
1739                                 }
1740
1741                                 decimal_digits (c);
1742                                 c = peek_char ();
1743                         }
1744
1745                         var type = real_type_suffix (c);
1746                         if (type == TypeCode.Empty && !is_real) {
1747                                 res = adjust_int (c, loc);
1748                         } else {
1749                                 is_real = true;
1750
1751                                 if (type != TypeCode.Empty) {
1752                                         get_char ();
1753                                 }
1754
1755                                 res = adjust_real (type, loc);
1756                         }
1757
1758                         val = res;
1759
1760 #if FULL_AST
1761                         var chars = reader.ReadChars (read_start, reader.Position - (type == TypeCode.Empty && c > 0 ? 1 : 0));
1762                         if (chars[chars.Length - 1] == '\r')
1763                                 Array.Resize (ref chars, chars.Length - 1);
1764                         res.ParsedValue = chars;
1765 #endif
1766
1767                         return Token.LITERAL;
1768                 }
1769
1770                 //
1771                 // Accepts exactly count (4 or 8) hex, no more no less
1772                 //
1773                 int getHex (int count, out int surrogate, out bool error)
1774                 {
1775                         int i;
1776                         int total = 0;
1777                         int c;
1778                         int top = count != -1 ? count : 4;
1779
1780                         get_char ();
1781                         error = false;
1782                         surrogate = 0;
1783                         for (i = 0; i < top; i++){
1784                                 c = get_char ();
1785
1786                                 if (c >= '0' && c <= '9')
1787                                         c = (int) c - (int) '0';
1788                                 else if (c >= 'A' && c <= 'F')
1789                                         c = (int) c - (int) 'A' + 10;
1790                                 else if (c >= 'a' && c <= 'f')
1791                                         c = (int) c - (int) 'a' + 10;
1792                                 else {
1793                                         error = true;
1794                                         return 0;
1795                                 }
1796
1797                                 total = (total * 16) + c;
1798                                 if (count == -1){
1799                                         int p = peek_char ();
1800                                         if (p == -1)
1801                                                 break;
1802                                         if (!is_hex ((char)p))
1803                                                 break;
1804                                 }
1805                         }
1806
1807                         if (top == 8) {
1808                                 if (total > 0x0010FFFF) {
1809                                         error = true;
1810                                         return 0;
1811                                 }
1812
1813                                 if (total >= 0x00010000) {
1814                                         surrogate = ((total - 0x00010000) % 0x0400 + 0xDC00);
1815                                         total = ((total - 0x00010000) / 0x0400 + 0xD800);
1816                                 }
1817                         }
1818
1819                         return total;
1820                 }
1821
1822                 int escape (int c, out int surrogate)
1823                 {
1824                         bool error;
1825                         int d;
1826                         int v;
1827
1828                         d = peek_char ();
1829                         if (c != '\\') {
1830                                 surrogate = 0;
1831                                 return c;
1832                         }
1833
1834                         switch (d){
1835                         case 'a':
1836                                 v = '\a'; break;
1837                         case 'b':
1838                                 v = '\b'; break;
1839                         case 'n':
1840                                 v = '\n'; break;
1841                         case 't':
1842                                 v = '\t'; break;
1843                         case 'v':
1844                                 v = '\v'; break;
1845                         case 'r':
1846                                 v = '\r'; break;
1847                         case '\\':
1848                                 v = '\\'; break;
1849                         case 'f':
1850                                 v = '\f'; break;
1851                         case '0':
1852                                 v = 0; break;
1853                         case '"':
1854                                 v = '"'; break;
1855                         case '\'':
1856                                 v = '\''; break;
1857                         case 'x':
1858                                 v = getHex (-1, out surrogate, out error);
1859                                 if (error)
1860                                         goto default;
1861                                 return v;
1862                         case 'u':
1863                         case 'U':
1864                                 return EscapeUnicode (d, out surrogate);
1865                         default:
1866                                 surrogate = 0;
1867                                 Report.Error (1009, Location, "Unrecognized escape sequence `\\{0}'", ((char)d).ToString ());
1868                                 return d;
1869                         }
1870
1871                         get_char ();
1872                         surrogate = 0;
1873                         return v;
1874                 }
1875
1876                 int EscapeUnicode (int ch, out int surrogate)
1877                 {
1878                         bool error;
1879                         if (ch == 'U') {
1880                                 ch = getHex (8, out surrogate, out error);
1881                         } else {
1882                                 ch = getHex (4, out surrogate, out error);
1883                         }
1884
1885                         if (error)
1886                                 Report.Error (1009, Location, "Unrecognized escape sequence");
1887
1888                         return ch;
1889                 }
1890
1891                 int get_char ()
1892                 {
1893                         int x;
1894                         if (putback_char != -1) {
1895                                 x = putback_char;
1896                                 putback_char = -1;
1897                         } else {
1898                                 x = reader.Read ();
1899                         }
1900
1901                         if (x <= 13) {
1902                                 if (x == '\r') {
1903                                         if (peek_char () == '\n') {
1904                                                 putback_char = -1;
1905                                         }
1906
1907                                         x = '\n';
1908                                         advance_line ();
1909                                 } else if (x == '\n') {
1910                                         advance_line ();
1911                                 } else {
1912                                         col++;
1913                                 }
1914                         } else if (x >= UnicodeLS && x <= UnicodePS) {
1915                                 advance_line ();
1916                         } else {
1917                                 col++;
1918                         }
1919
1920                         return x;
1921                 }
1922
1923                 void advance_line ()
1924                 {
1925                         line++;
1926                         ref_line++;
1927                         previous_col = col;
1928                         col = 0;
1929                 }
1930
1931                 int peek_char ()
1932                 {
1933                         if (putback_char == -1)
1934                                 putback_char = reader.Read ();
1935                         return putback_char;
1936                 }
1937
1938                 int peek_char2 ()
1939                 {
1940                         if (putback_char != -1)
1941                                 return putback_char;
1942                         return reader.Peek ();
1943                 }
1944
1945                 public void putback (int c)
1946                 {
1947                         if (putback_char != -1) {
1948                                 throw new InternalErrorException (string.Format ("Secondary putback [{0}] putting back [{1}] is not allowed", (char)putback_char, (char) c), Location);
1949                         }
1950
1951                         if (c == '\n' || col == 0 || (c >= UnicodeLS && c <= UnicodePS)) {
1952                                 // It won't happen though.
1953                                 line--;
1954                                 ref_line--;
1955                                 col = previous_col;
1956                         }
1957                         else
1958                                 col--;
1959                         putback_char = c;
1960                 }
1961
1962                 public bool advance ()
1963                 {
1964                         return peek_char () != -1 || CompleteOnEOF;
1965                 }
1966
1967                 public Object Value {
1968                         get {
1969                                 return val;
1970                         }
1971                 }
1972
1973                 public Object value ()
1974                 {
1975                         return val;
1976                 }
1977
1978                 public int token ()
1979                 {
1980                         current_token = xtoken ();
1981                         return current_token;
1982                 }
1983
1984                 int TokenizePreprocessorIdentifier (out int c)
1985                 {
1986                         // skip over white space
1987                         do {
1988                                 c = get_char ();
1989                         } while (c == ' ' || c == '\t');
1990
1991
1992                         int pos = 0;
1993                         while (c != -1 && c >= 'a' && c <= 'z') {
1994                                 id_builder[pos++] = (char) c;
1995                                 c = get_char ();
1996                                 if (c == '\\') {
1997                                         int peek = peek_char ();
1998                                         if (peek == 'U' || peek == 'u') {
1999                                                 int surrogate;
2000                                                 c = EscapeUnicode (c, out surrogate);
2001                                                 if (surrogate != 0) {
2002                                                         if (is_identifier_part_character ((char) c)) {
2003                                                                 id_builder[pos++] = (char) c;
2004                                                         }
2005                                                         c = surrogate;
2006                                                 }
2007                                         }
2008                                 }
2009                         }
2010
2011                         return pos;
2012                 }
2013
2014                 PreprocessorDirective get_cmd_arg (out string arg)
2015                 {
2016                         int c;
2017
2018                         tokens_seen = false;
2019                         arg = "";
2020
2021                         var cmd = GetPreprocessorDirective (id_builder, TokenizePreprocessorIdentifier (out c));
2022
2023                         if ((cmd & PreprocessorDirective.CustomArgumentsParsing) != 0)
2024                                 return cmd;
2025
2026                         // skip over white space
2027                         while (c == ' ' || c == '\t')
2028                                 c = get_char ();
2029
2030                         int has_identifier_argument = (int)(cmd & PreprocessorDirective.RequiresArgument);
2031                         int pos = 0;
2032
2033                         while (c != -1 && c != '\n' && c != UnicodeLS && c != UnicodePS) {
2034                                 if (c == '\\' && has_identifier_argument >= 0) {
2035                                         if (has_identifier_argument != 0) {
2036                                                 has_identifier_argument = 1;
2037
2038                                                 int peek = peek_char ();
2039                                                 if (peek == 'U' || peek == 'u') {
2040                                                         int surrogate;
2041                                                         c = EscapeUnicode (c, out surrogate);
2042                                                         if (surrogate != 0) {
2043                                                                 if (is_identifier_part_character ((char) c)) {
2044                                                                         if (pos == value_builder.Length)
2045                                                                                 Array.Resize (ref value_builder, pos * 2);
2046
2047                                                                         value_builder[pos++] = (char) c;
2048                                                                 }
2049                                                                 c = surrogate;
2050                                                         }
2051                                                 }
2052                                         } else {
2053                                                 has_identifier_argument = -1;
2054                                         }
2055                                 } else if (c == '/' && peek_char () == '/') {
2056                                         //
2057                                         // Eat single-line comments
2058                                         //
2059                                         get_char ();
2060                                         ReadToEndOfLine ();
2061                                         break;
2062                                 }
2063
2064                                 if (pos == value_builder.Length)
2065                                         Array.Resize (ref value_builder, pos * 2);
2066
2067                                 value_builder[pos++] = (char) c;
2068                                 c = get_char ();
2069                         }
2070
2071                         if (pos != 0) {
2072                                 if (pos > MaxIdentifierLength)
2073                                         arg = new string (value_builder, 0, pos);
2074                                 else
2075                                         arg = InternIdentifier (value_builder, pos);
2076
2077                                 // Eat any trailing whitespaces
2078                                 arg = arg.Trim (simple_whitespaces);
2079                         }
2080
2081                         return cmd;
2082                 }
2083
2084                 //
2085                 // Handles the #line directive
2086                 //
2087                 bool PreProcessLine ()
2088                 {
2089                         Location loc = Location;
2090
2091                         int c;
2092
2093                         int length = TokenizePreprocessorIdentifier (out c);
2094                         if (length == line_default.Length) {
2095                                 if (!IsTokenIdentifierEqual (line_default))
2096                                         return false;
2097
2098                                 current_source = source_file.SourceFile;
2099                                 if (!hidden_block_start.IsNull) {
2100                                         current_source.RegisterHiddenScope (hidden_block_start, loc);
2101                                         hidden_block_start = Location.Null;
2102                                 }
2103
2104                                 ref_line = line;
2105                                 return true;
2106                         }
2107
2108                         if (length == line_hidden.Length) {
2109                                 if (!IsTokenIdentifierEqual (line_hidden))
2110                                         return false;
2111
2112                                 if (hidden_block_start.IsNull)
2113                                         hidden_block_start = loc;
2114
2115                                 return true;
2116                         }
2117
2118                         if (length != 0 || c < '0' || c > '9') {
2119                                 //
2120                                 // Eat any remaining characters to continue parsing on next line
2121                                 //
2122                                 ReadToEndOfLine ();
2123                                 return false;
2124                         }
2125
2126                         int new_line = TokenizeNumber (c);
2127                         if (new_line < 1) {
2128                                 //
2129                                 // Eat any remaining characters to continue parsing on next line
2130                                 //
2131                                 ReadToEndOfLine ();
2132                                 return new_line != 0;
2133                         }
2134
2135                         c = get_char ();
2136                         if (c == ' ') {
2137                                 // skip over white space
2138                                 do {
2139                                         c = get_char ();
2140                                 } while (c == ' ' || c == '\t');
2141                         } else if (c == '"') {
2142                                 c = 0;
2143                         }
2144
2145                         if (c != '\n' && c != '/' && c != '"' && c != UnicodeLS && c != UnicodePS) {
2146                                 //
2147                                 // Eat any remaining characters to continue parsing on next line
2148                                 //
2149                                 ReadToEndOfLine ();
2150
2151                                 Report.Error (1578, loc, "Filename, single-line comment or end-of-line expected");
2152                                 return true;
2153                         }
2154
2155                         string new_file_name = null;
2156                         if (c == '"') {
2157                                 new_file_name = TokenizeFileName (ref c);
2158
2159                                 // skip over white space
2160                                 while (c == ' ' || c == '\t') {
2161                                         c = get_char ();
2162                                 }
2163                         }
2164
2165                         if (c == '\n' || c == UnicodeLS || c == UnicodePS) {
2166
2167                         } else if (c == '/') {
2168                                 ReadSingleLineComment ();
2169                         } else {
2170                                 //
2171                                 // Eat any remaining characters to continue parsing on next line
2172                                 //
2173                                 ReadToEndOfLine ();
2174
2175                                 Error_EndLineExpected ();
2176                                 return true;
2177                         }
2178
2179                         if (new_file_name != null) {
2180                                 current_source = context.LookupFile (source_file, new_file_name);
2181                                 source_file.AddIncludeFile (current_source);
2182                         }
2183
2184                         if (!hidden_block_start.IsNull) {
2185                                 current_source.RegisterHiddenScope (hidden_block_start, loc);
2186                                 hidden_block_start = Location.Null;
2187                         }
2188
2189                         ref_line = new_line;
2190                         return true;
2191                 }
2192
2193                 //
2194                 // Handles #define and #undef
2195                 //
2196                 void PreProcessDefinition (bool is_define, string ident, bool caller_is_taking)
2197                 {
2198                         if (ident.Length == 0 || ident == "true" || ident == "false"){
2199                                 Report.Error (1001, Location, "Missing identifier to pre-processor directive");
2200                                 return;
2201                         }
2202
2203                         if (ident.IndexOfAny (simple_whitespaces) != -1){
2204                                 Error_EndLineExpected ();
2205                                 return;
2206                         }
2207
2208                         if (!is_identifier_start_character (ident [0]))
2209                                 Report.Error (1001, Location, "Identifier expected: {0}", ident);
2210
2211                         foreach (char c in ident.Substring (1)){
2212                                 if (!is_identifier_part_character (c)){
2213                                         Report.Error (1001, Location, "Identifier expected: {0}",  ident);
2214                                         return;
2215                                 }
2216                         }
2217
2218                         if (!caller_is_taking)
2219                                 return;
2220
2221                         if (is_define) {
2222                                 //
2223                                 // #define ident
2224                                 //
2225                                 if (context.Settings.IsConditionalSymbolDefined (ident))
2226                                         return;
2227
2228                                 source_file.AddDefine (ident);
2229                         } else {
2230                                 //
2231                                 // #undef ident
2232                                 //
2233                                 source_file.AddUndefine (ident);
2234                         }
2235                 }
2236
2237                 byte read_hex (out bool error)
2238                 {
2239                         int total;
2240                         int c = get_char ();
2241
2242                         if ((c >= '0') && (c <= '9'))
2243                                 total = (int) c - (int) '0';
2244                         else if ((c >= 'A') && (c <= 'F'))
2245                                 total = (int) c - (int) 'A' + 10;
2246                         else if ((c >= 'a') && (c <= 'f'))
2247                                 total = (int) c - (int) 'a' + 10;
2248                         else {
2249                                 error = true;
2250                                 return 0;
2251                         }
2252
2253                         total *= 16;
2254                         c = get_char ();
2255
2256                         if ((c >= '0') && (c <= '9'))
2257                                 total += (int) c - (int) '0';
2258                         else if ((c >= 'A') && (c <= 'F'))
2259                                 total += (int) c - (int) 'A' + 10;
2260                         else if ((c >= 'a') && (c <= 'f'))
2261                                 total += (int) c - (int) 'a' + 10;
2262                         else {
2263                                 error = true;
2264                                 return 0;
2265                         }
2266
2267                         error = false;
2268                         return (byte) total;
2269                 }
2270
2271                 //
2272                 // Parses #pragma checksum
2273                 //
2274                 bool ParsePragmaChecksum ()
2275                 {
2276                         //
2277                         // The syntax is ` "foo.txt" "{guid}" "hash"'
2278                         //
2279                         // guid is predefined hash algorithm guid {406ea660-64cf-4c82-b6f0-42d48172a799} for md5
2280                         //
2281                         int c = get_char ();
2282
2283                         if (c != '"')
2284                                 return false;
2285
2286                         string file_name = TokenizeFileName (ref c);
2287
2288                         // TODO: Any white-spaces count
2289                         if (c != ' ')
2290                                 return false;
2291
2292                         SourceFile file = context.LookupFile (source_file, file_name);
2293
2294                         if (get_char () != '"' || get_char () != '{')
2295                                 return false;
2296
2297                         bool error;
2298                         byte[] guid_bytes = new byte [16];
2299                         int i = 0;
2300
2301                         for (; i < 4; i++) {
2302                                 guid_bytes [i] = read_hex (out error);
2303                                 if (error)
2304                                         return false;
2305                         }
2306
2307                         if (get_char () != '-')
2308                                 return false;
2309
2310                         for (; i < 10; i++) {
2311                                 guid_bytes [i] = read_hex (out error);
2312                                 if (error)
2313                                         return false;
2314
2315                                 guid_bytes [i++] = read_hex (out error);
2316                                 if (error)
2317                                         return false;
2318
2319                                 if (get_char () != '-')
2320                                         return false;
2321                         }
2322
2323                         for (; i < 16; i++) {
2324                                 guid_bytes [i] = read_hex (out error);
2325                                 if (error)
2326                                         return false;
2327                         }
2328
2329                         if (get_char () != '}' || get_char () != '"')
2330                                 return false;
2331
2332                         // TODO: Any white-spaces count
2333                         c = get_char ();
2334                         if (c != ' ')
2335                                 return false;
2336
2337                         if (get_char () != '"')
2338                                 return false;
2339
2340                         // Any length of checksum
2341                         List<byte> checksum_bytes = new List<byte> (16);
2342
2343                         var checksum_location = Location;
2344                         c = peek_char ();
2345                         while (c != '"' && c != -1) {
2346                                 checksum_bytes.Add (read_hex (out error));
2347                                 if (error)
2348                                         return false;
2349
2350                                 c = peek_char ();
2351                         }
2352
2353                         if (c == '/') {
2354                                 ReadSingleLineComment ();
2355                         } else if (get_char () != '"') {
2356                                 return false;
2357                         }
2358
2359                         if (context.Settings.GenerateDebugInfo) {
2360                                 var chsum = checksum_bytes.ToArray ();
2361
2362                                 if (file.HasChecksum) {
2363                                         if (!ArrayComparer.IsEqual (file.Checksum, chsum)) {
2364                                                 // TODO: Report.SymbolRelatedToPreviousError
2365                                                 Report.Warning (1697, 1, checksum_location, "Different checksum values specified for file `{0}'", file.Name);
2366                                         }
2367                                 }
2368
2369                                 file.SetChecksum (guid_bytes, chsum);
2370                                 current_source.AutoGenerated = true;
2371                         }
2372
2373                         return true;
2374                 }
2375
2376                 bool IsTokenIdentifierEqual (char[] identifier)
2377                 {
2378                         for (int i = 0; i < identifier.Length; ++i) {
2379                                 if (identifier[i] != id_builder[i])
2380                                         return false;
2381                         }
2382
2383                         return true;
2384                 }
2385
2386                 int TokenizeNumber (int value)
2387                 {
2388                         number_pos = 0;
2389
2390                         decimal_digits (value);
2391                         uint ui = (uint) (number_builder[0] - '0');
2392
2393                         try {
2394                                 for (int i = 1; i < number_pos; i++) {
2395                                         ui = checked ((ui * 10) + ((uint) (number_builder[i] - '0')));
2396                                 }
2397
2398                                 return (int) ui;
2399                         } catch (OverflowException) {
2400                                 Error_NumericConstantTooLong ();
2401                                 return -1;
2402                         }
2403                 }
2404
2405                 string TokenizeFileName (ref int c)
2406                 {
2407                         var string_builder = new StringBuilder ();
2408                         while (c != -1 && c != '\n' && c != UnicodeLS && c != UnicodePS) {
2409                                 c = get_char ();
2410                                 if (c == '"') {
2411                                         c = get_char ();
2412                                         break;
2413                                 }
2414
2415                                 string_builder.Append ((char) c);
2416                         }
2417
2418                         if (string_builder.Length == 0) {
2419                                 Report.Warning (1709, 1, Location, "Filename specified for preprocessor directive is empty");
2420                         }
2421
2422
2423                         return string_builder.ToString ();
2424                 }
2425
2426                 int TokenizePragmaNumber (ref int c)
2427                 {
2428                         number_pos = 0;
2429
2430                         int number;
2431
2432                         if (c >= '0' && c <= '9') {
2433                                 number = TokenizeNumber (c);
2434
2435                                 c = get_char ();
2436
2437                                 // skip over white space
2438                                 while (c == ' ' || c == '\t')
2439                                         c = get_char ();
2440
2441                                 if (c == ',') {
2442                                         c = get_char ();
2443                                 }
2444
2445                                 // skip over white space
2446                                 while (c == ' ' || c == '\t')
2447                                         c = get_char ();
2448                         } else {
2449                                 number = -1;
2450                                 if (c == '/') {
2451                                         ReadSingleLineComment ();
2452                                 } else {
2453                                         Report.Warning (1692, 1, Location, "Invalid number");
2454
2455                                         // Read everything till the end of the line or file
2456                                         ReadToEndOfLine ();
2457                                 }
2458                         }
2459
2460                         return number;
2461                 }
2462
2463                 void ReadToEndOfLine ()
2464                 {
2465                         int c;
2466                         do {
2467                                 c = get_char ();
2468                         } while (c != -1 && c != '\n' && c != UnicodeLS && c != UnicodePS);
2469                 }
2470
2471                 void ReadSingleLineComment ()
2472                 {
2473                         if (peek_char () != '/')
2474                                 Report.Warning (1696, 1, Location, "Single-line comment or end-of-line expected");
2475
2476                         // Read everything till the end of the line or file
2477                         ReadToEndOfLine ();
2478                 }
2479
2480                 /// <summary>
2481                 /// Handles #pragma directive
2482                 /// </summary>
2483                 void ParsePragmaDirective ()
2484                 {
2485                         int c;
2486                         int length = TokenizePreprocessorIdentifier (out c);
2487                         if (length == pragma_warning.Length && IsTokenIdentifierEqual (pragma_warning)) {
2488                                 length = TokenizePreprocessorIdentifier (out c);
2489
2490                                 //
2491                                 // #pragma warning disable
2492                                 // #pragma warning restore
2493                                 //
2494                                 if (length == pragma_warning_disable.Length) {
2495                                         bool disable = IsTokenIdentifierEqual (pragma_warning_disable);
2496                                         if (disable || IsTokenIdentifierEqual (pragma_warning_restore)) {
2497                                                 // skip over white space
2498                                                 while (c == ' ' || c == '\t')
2499                                                         c = get_char ();
2500
2501                                                 var loc = Location;
2502
2503                                                 if (c == '\n' || c == '/' || c == UnicodeLS || c == UnicodePS) {
2504                                                         if (c == '/')
2505                                                                 ReadSingleLineComment ();
2506
2507                                                         //
2508                                                         // Disable/Restore all warnings
2509                                                         //
2510                                                         if (disable) {
2511                                                                 Report.RegisterWarningRegion (loc).WarningDisable (loc.Row);
2512                                                         } else {
2513                                                                 Report.RegisterWarningRegion (loc).WarningEnable (loc.Row);
2514                                                         }
2515                                                 } else {
2516                                                         //
2517                                                         // Disable/Restore a warning or group of warnings
2518                                                         //
2519                                                         int code;
2520                                                         do {
2521                                                                 code = TokenizePragmaNumber (ref c);
2522                                                                 if (code > 0) {
2523                                                                         if (disable) {
2524                                                                                 Report.RegisterWarningRegion (loc).WarningDisable (loc, code, context.Report);
2525                                                                         } else {
2526                                                                                 Report.RegisterWarningRegion (loc).WarningEnable (loc, code, context);
2527                                                                         }
2528                                                                 }
2529                                                         } while (code >= 0 && c != '\n' && c != -1 && c != UnicodeLS && c != UnicodePS);
2530                                                 }
2531
2532                                                 return;
2533                                         }
2534                                 }
2535
2536                                 Report.Warning (1634, 1, Location, "Expected disable or restore");
2537
2538                                 // Eat any remaining characters on the line
2539                                 ReadToEndOfLine ();
2540
2541                                 return;
2542                         }
2543
2544                         //
2545                         // #pragma checksum
2546                         //
2547                         if (length == pragma_checksum.Length && IsTokenIdentifierEqual (pragma_checksum)) {
2548                                 if (c != ' ' || !ParsePragmaChecksum ()) {
2549                                         Report.Warning (1695, 1, Location,
2550                                                 "Invalid #pragma checksum syntax. Expected \"filename\" \"{XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX}\" \"XXXX...\"");
2551                                 }
2552
2553                                 return;
2554                         }
2555
2556                         Report.Warning (1633, 1, Location, "Unrecognized #pragma directive");
2557                 }
2558
2559                 bool eval_val (string s)
2560                 {
2561                         if (s == "true")
2562                                 return true;
2563                         if (s == "false")
2564                                 return false;
2565
2566                         return source_file.IsConditionalDefined (s);
2567                 }
2568
2569                 bool pp_primary (ref string s)
2570                 {
2571                         s = s.Trim ();
2572                         int len = s.Length;
2573
2574                         if (len > 0){
2575                                 char c = s [0];
2576
2577                                 if (c == '('){
2578                                         s = s.Substring (1);
2579                                         bool val = pp_expr (ref s, false);
2580                                         if (s.Length > 0 && s [0] == ')'){
2581                                                 s = s.Substring (1);
2582                                                 return val;
2583                                         }
2584                                         Error_InvalidDirective ();
2585                                         return false;
2586                                 }
2587
2588                                 if (is_identifier_start_character (c)){
2589                                         int j = 1;
2590
2591                                         while (j < len){
2592                                                 c = s [j];
2593
2594                                                 if (is_identifier_part_character (c)){
2595                                                         j++;
2596                                                         continue;
2597                                                 }
2598                                                 bool v = eval_val (s.Substring (0, j));
2599                                                 s = s.Substring (j);
2600                                                 return v;
2601                                         }
2602                                         bool vv = eval_val (s);
2603                                         s = "";
2604                                         return vv;
2605                                 }
2606                         }
2607                         Error_InvalidDirective ();
2608                         return false;
2609                 }
2610
2611                 bool pp_unary (ref string s)
2612                 {
2613                         s = s.Trim ();
2614                         int len = s.Length;
2615
2616                         if (len > 0){
2617                                 if (s [0] == '!'){
2618                                         if (len > 1 && s [1] == '='){
2619                                                 Error_InvalidDirective ();
2620                                                 return false;
2621                                         }
2622                                         s = s.Substring (1);
2623                                         return ! pp_primary (ref s);
2624                                 } else
2625                                         return pp_primary (ref s);
2626                         } else {
2627                                 Error_InvalidDirective ();
2628                                 return false;
2629                         }
2630                 }
2631
2632                 bool pp_eq (ref string s)
2633                 {
2634                         bool va = pp_unary (ref s);
2635
2636                         s = s.Trim ();
2637                         int len = s.Length;
2638                         if (len > 0){
2639                                 if (s [0] == '='){
2640                                         if (len > 2 && s [1] == '='){
2641                                                 s = s.Substring (2);
2642                                                 return va == pp_unary (ref s);
2643                                         } else {
2644                                                 Error_InvalidDirective ();
2645                                                 return false;
2646                                         }
2647                                 } else if (s [0] == '!' && len > 1 && s [1] == '='){
2648                                         s = s.Substring (2);
2649
2650                                         return va != pp_unary (ref s);
2651
2652                                 }
2653                         }
2654
2655                         return va;
2656
2657                 }
2658
2659                 bool pp_and (ref string s)
2660                 {
2661                         bool va = pp_eq (ref s);
2662
2663                         s = s.Trim ();
2664                         int len = s.Length;
2665                         if (len > 0){
2666                                 if (s [0] == '&'){
2667                                         if (len > 2 && s [1] == '&'){
2668                                                 s = s.Substring (2);
2669                                                 return (va & pp_and (ref s));
2670                                         } else {
2671                                                 Error_InvalidDirective ();
2672                                                 return false;
2673                                         }
2674                                 }
2675                         }
2676                         return va;
2677                 }
2678
2679                 //
2680                 // Evaluates an expression for `#if' or `#elif'
2681                 //
2682                 bool pp_expr (ref string s, bool isTerm)
2683                 {
2684                         bool va = pp_and (ref s);
2685                         s = s.Trim ();
2686                         int len = s.Length;
2687                         if (len > 0){
2688                                 char c = s [0];
2689
2690                                 if (c == '|'){
2691                                         if (len > 2 && s [1] == '|'){
2692                                                 s = s.Substring (2);
2693                                                 return va | pp_expr (ref s, isTerm);
2694                                         } else {
2695                                                 Error_InvalidDirective ();
2696                                                 return false;
2697                                         }
2698                                 }
2699                                 if (isTerm) {
2700                                         Error_EndLineExpected ();
2701                                         return false;
2702                                 }
2703                         }
2704
2705                         return va;
2706                 }
2707
2708                 bool eval (string s)
2709                 {
2710                         bool v = pp_expr (ref s, true);
2711                         s = s.Trim ();
2712                         if (s.Length != 0){
2713                                 return false;
2714                         }
2715
2716                         return v;
2717                 }
2718
2719                 void Error_NumericConstantTooLong ()
2720                 {
2721                         Report.Error (1021, Location, "Integral constant is too large");
2722                 }
2723
2724                 void Error_InvalidDirective ()
2725                 {
2726                         Report.Error (1517, Location, "Invalid preprocessor directive");
2727                 }
2728
2729                 void Error_UnexpectedDirective (string extra)
2730                 {
2731                         Report.Error (
2732                                 1028, Location,
2733                                 "Unexpected processor directive ({0})", extra);
2734                 }
2735
2736                 void Error_TokensSeen ()
2737                 {
2738                         Report.Error (1032, Location,
2739                                 "Cannot define or undefine preprocessor symbols after first token in file");
2740                 }
2741
2742                 void Eror_WrongPreprocessorLocation ()
2743                 {
2744                         Report.Error (1040, Location,
2745                                 "Preprocessor directives must appear as the first non-whitespace character on a line");
2746                 }
2747
2748                 void Error_EndLineExpected ()
2749                 {
2750                         Report.Error (1025, Location, "Single-line comment or end-of-line expected");
2751                 }
2752
2753                 //
2754                 // Raises a warning when tokenizer found documentation comment
2755                 // on unexpected place
2756                 //
2757                 void WarningMisplacedComment (Location loc)
2758                 {
2759                         if (doc_state != XmlCommentState.Error) {
2760                                 doc_state = XmlCommentState.Error;
2761                                 Report.Warning (1587, 2, loc, "XML comment is not placed on a valid language element");
2762                         }
2763                 }
2764
2765                 //
2766                 // if true, then the code continues processing the code
2767                 // if false, the code stays in a loop until another directive is
2768                 // reached.
2769                 // When caller_is_taking is false we ignore all directives except the ones
2770                 // which can help us to identify where the #if block ends
2771                 bool ParsePreprocessingDirective (bool caller_is_taking)
2772                 {
2773                         string arg;
2774                         bool region_directive = false;
2775
2776                         var directive = get_cmd_arg (out arg);
2777
2778                         //
2779                         // The first group of pre-processing instructions is always processed
2780                         //
2781                         switch (directive) {
2782                         case PreprocessorDirective.Region:
2783                                 region_directive = true;
2784                                 arg = "true";
2785                                 goto case PreprocessorDirective.If;
2786
2787                         case PreprocessorDirective.Endregion:
2788                                 if (ifstack == null || ifstack.Count == 0){
2789                                         Error_UnexpectedDirective ("no #region for this #endregion");
2790                                         return true;
2791                                 }
2792                                 int pop = ifstack.Pop ();
2793
2794                                 if ((pop & REGION) == 0)
2795                                         Report.Error (1027, Location, "Expected `#endif' directive");
2796
2797                                 return caller_is_taking;
2798
2799                         case PreprocessorDirective.If:
2800                                 if (ifstack == null)
2801                                         ifstack = new Stack<int> (2);
2802
2803                                 int flags = region_directive ? REGION : 0;
2804                                 if (ifstack.Count == 0){
2805                                         flags |= PARENT_TAKING;
2806                                 } else {
2807                                         int state = ifstack.Peek ();
2808                                         if ((state & TAKING) != 0) {
2809                                                 flags |= PARENT_TAKING;
2810                                         }
2811                                 }
2812
2813                                 if (eval (arg) && caller_is_taking) {
2814                                         ifstack.Push (flags | TAKING);
2815                                         return true;
2816                                 }
2817                                 ifstack.Push (flags);
2818                                 return false;
2819
2820                         case PreprocessorDirective.Endif:
2821                                 if (ifstack == null || ifstack.Count == 0){
2822                                         Error_UnexpectedDirective ("no #if for this #endif");
2823                                         return true;
2824                                 } else {
2825                                         pop = ifstack.Pop ();
2826
2827                                         if ((pop & REGION) != 0)
2828                                                 Report.Error (1038, Location, "#endregion directive expected");
2829
2830                                         if (arg.Length != 0) {
2831                                                 Error_EndLineExpected ();
2832                                         }
2833
2834                                         if (ifstack.Count == 0)
2835                                                 return true;
2836
2837                                         int state = ifstack.Peek ();
2838                                         return (state & TAKING) != 0;
2839                                 }
2840
2841                         case PreprocessorDirective.Elif:
2842                                 if (ifstack == null || ifstack.Count == 0){
2843                                         Error_UnexpectedDirective ("no #if for this #elif");
2844                                         return true;
2845                                 } else {
2846                                         int state = ifstack.Pop ();
2847
2848                                         if ((state & REGION) != 0) {
2849                                                 Report.Error (1038, Location, "#endregion directive expected");
2850                                                 return true;
2851                                         }
2852
2853                                         if ((state & ELSE_SEEN) != 0){
2854                                                 Error_UnexpectedDirective ("#elif not valid after #else");
2855                                                 return true;
2856                                         }
2857
2858                                         if ((state & TAKING) != 0) {
2859                                                 ifstack.Push (0);
2860                                                 return false;
2861                                         }
2862
2863                                         if (eval (arg) && ((state & PARENT_TAKING) != 0)){
2864                                                 ifstack.Push (state | TAKING);
2865                                                 return true;
2866                                         }
2867
2868                                         ifstack.Push (state);
2869                                         return false;
2870                                 }
2871
2872                         case PreprocessorDirective.Else:
2873                                 if (ifstack == null || ifstack.Count == 0){
2874                                         Error_UnexpectedDirective ("no #if for this #else");
2875                                         return true;
2876                                 } else {
2877                                         int state = ifstack.Peek ();
2878
2879                                         if ((state & REGION) != 0) {
2880                                                 Report.Error (1038, Location, "#endregion directive expected");
2881                                                 return true;
2882                                         }
2883
2884                                         if ((state & ELSE_SEEN) != 0){
2885                                                 Error_UnexpectedDirective ("#else within #else");
2886                                                 return true;
2887                                         }
2888
2889                                         ifstack.Pop ();
2890
2891                                         if (arg.Length != 0) {
2892                                                 Error_EndLineExpected ();
2893                                                 return true;
2894                                         }
2895
2896                                         bool ret = false;
2897                                         if ((state & PARENT_TAKING) != 0) {
2898                                                 ret = (state & TAKING) == 0;
2899
2900                                                 if (ret)
2901                                                         state |= TAKING;
2902                                                 else
2903                                                         state &= ~TAKING;
2904                                         }
2905
2906                                         ifstack.Push (state | ELSE_SEEN);
2907
2908                                         return ret;
2909                                 }
2910                         case PreprocessorDirective.Define:
2911                                 if (any_token_seen){
2912                                         if (caller_is_taking)
2913                                                 Error_TokensSeen ();
2914                                         return caller_is_taking;
2915                                 }
2916                                 PreProcessDefinition (true, arg, caller_is_taking);
2917                                 return caller_is_taking;
2918
2919                         case PreprocessorDirective.Undef:
2920                                 if (any_token_seen){
2921                                         if (caller_is_taking)
2922                                                 Error_TokensSeen ();
2923                                         return caller_is_taking;
2924                                 }
2925                                 PreProcessDefinition (false, arg, caller_is_taking);
2926                                 return caller_is_taking;
2927
2928                         case PreprocessorDirective.Invalid:
2929                                 Report.Error (1024, Location, "Wrong preprocessor directive");
2930                                 return true;
2931                         }
2932
2933                         //
2934                         // These are only processed if we are in a `taking' block
2935                         //
2936                         if (!caller_is_taking)
2937                                 return false;
2938
2939                         switch (directive){
2940                         case PreprocessorDirective.Error:
2941                                 Report.Error (1029, Location, "#error: '{0}'", arg);
2942                                 return true;
2943
2944                         case PreprocessorDirective.Warning:
2945                                 Report.Warning (1030, 1, Location, "#warning: `{0}'", arg);
2946                                 return true;
2947
2948                         case PreprocessorDirective.Pragma:
2949                                 if (context.Settings.Version == LanguageVersion.ISO_1) {
2950                                         Report.FeatureIsNotAvailable (context, Location, "#pragma");
2951                                 }
2952
2953                                 ParsePragmaDirective ();
2954                                 return true;
2955
2956                         case PreprocessorDirective.Line:
2957                                 Location loc = Location;
2958                                 if (!PreProcessLine ())
2959                                         Report.Error (1576, loc, "The line number specified for #line directive is missing or invalid");
2960
2961                                 return caller_is_taking;
2962                         }
2963
2964                         throw new NotImplementedException (directive.ToString ());
2965                 }
2966
2967                 private int consume_string (bool quoted)
2968                 {
2969                         int c;
2970                         int pos = 0;
2971                         Location start_location = Location;
2972                         if (quoted)
2973                                 start_location = start_location - 1;
2974
2975 #if FULL_AST
2976                         int reader_pos = reader.Position;
2977 #endif
2978
2979                         while (true){
2980                                 // Cannot use get_char because of \r in quoted strings
2981                                 if (putback_char != -1) {
2982                                         c = putback_char;
2983                                         putback_char = -1;
2984                                 } else {
2985                                         c = reader.Read ();
2986                                 }
2987
2988                                 if (c == '"') {
2989                                         ++col;
2990
2991                                         if (quoted && peek_char () == '"') {
2992                                                 if (pos == value_builder.Length)
2993                                                         Array.Resize (ref value_builder, pos * 2);
2994
2995                                                 value_builder[pos++] = (char) c;
2996                                                 get_char ();
2997                                                 continue;
2998                                         }
2999
3000                                         string s;
3001                                         if (pos == 0)
3002                                                 s = string.Empty;
3003                                         else if (pos <= 4)
3004                                                 s = InternIdentifier (value_builder, pos);
3005                                         else
3006                                                 s = new string (value_builder, 0, pos);
3007
3008                                         ILiteralConstant res = new StringLiteral (context.BuiltinTypes, s, start_location);
3009                                         val = res;
3010 #if FULL_AST
3011                                         res.ParsedValue = quoted ?
3012                                                 reader.ReadChars (reader_pos - 2, reader.Position - 1) :
3013                                                 reader.ReadChars (reader_pos - 1, reader.Position);
3014 #endif
3015
3016                                         return Token.LITERAL;
3017                                 }
3018
3019                                 if (c == '\n' || c == UnicodeLS || c == UnicodePS) {
3020                                         if (!quoted) {
3021                                                 Report.Error (1010, Location, "Newline in constant");
3022
3023                                                 advance_line ();
3024
3025                                                 // Don't add \r to string literal
3026                                                 if (pos > 1 && value_builder [pos - 1] == '\r')
3027                                                         --pos;
3028
3029                                                 val = new StringLiteral (context.BuiltinTypes, new string (value_builder, 0, pos), start_location);
3030                                                 return Token.LITERAL;
3031                                         }
3032
3033                                         advance_line ();
3034                                 } else if (c == '\\' && !quoted) {
3035                                         ++col;
3036                                         int surrogate;
3037                                         c = escape (c, out surrogate);
3038                                         if (c == -1)
3039                                                 return Token.ERROR;
3040                                         if (surrogate != 0) {
3041                                                 if (pos == value_builder.Length)
3042                                                         Array.Resize (ref value_builder, pos * 2);
3043
3044                                                 value_builder[pos++] = (char) c;
3045                                                 c = surrogate;
3046                                         }
3047                                 } else if (c == -1) {
3048                                         Report.Error (1039, Location, "Unterminated string literal");
3049                                         return Token.EOF;
3050                                 } else {
3051                                         ++col;
3052                                 }
3053
3054                                 if (pos == value_builder.Length)
3055                                         Array.Resize (ref value_builder, pos * 2);
3056
3057                                 value_builder[pos++] = (char) c;
3058                         }
3059                 }
3060
3061                 private int consume_identifier (int s)
3062                 {
3063                         int res = consume_identifier (s, false);
3064
3065                         if (doc_state == XmlCommentState.Allowed)
3066                                 doc_state = XmlCommentState.NotAllowed;
3067
3068                         return res;
3069                 }
3070
3071                 int consume_identifier (int c, bool quoted)
3072                 {
3073                         //
3074                         // This method is very performance sensitive. It accounts
3075                         // for approximately 25% of all parser time
3076                         //
3077
3078                         int pos = 0;
3079                         int column = col;
3080                         if (quoted)
3081                                 --column;
3082
3083                         if (c == '\\') {
3084                                 int surrogate;
3085                                 c = escape (c, out surrogate);
3086                                 if (surrogate != 0) {
3087                                         id_builder [pos++] = (char) c;
3088                                         c = surrogate;
3089                                 }
3090                         }
3091
3092                         id_builder [pos++] = (char) c;
3093
3094                         try {
3095                                 while (true) {
3096                                         c = reader.Read ();
3097
3098                                         if ((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || c == '_' || (c >= '0' && c <= '9')) {
3099                                                 id_builder [pos++] = (char) c;
3100                                                 continue;
3101                                         }
3102
3103                                         if (c < 0x80) {
3104                                                 if (c == '\\') {
3105                                                         int surrogate;
3106                                                         c = escape (c, out surrogate);
3107                                                         if (is_identifier_part_character ((char) c))
3108                                                                 id_builder[pos++] = (char) c;
3109
3110                                                         if (surrogate != 0) {
3111                                                                 c = surrogate;
3112                                                         }
3113
3114                                                         continue;
3115                                                 }
3116                                         } else if (is_identifier_part_character_slow_part ((char) c)) {
3117                                                 id_builder [pos++] = (char) c;
3118                                                 continue;
3119                                         }
3120
3121                                         putback_char = c;
3122                                         break;
3123                                 }
3124                         } catch (IndexOutOfRangeException) {
3125                                 Report.Error (645, Location, "Identifier too long (limit is 512 chars)");
3126                                 --pos;
3127                                 col += pos;
3128                         }
3129
3130                         col += pos - 1;
3131
3132                         //
3133                         // Optimization: avoids doing the keyword lookup
3134                         // on uppercase letters
3135                         //
3136                         if (id_builder [0] >= '_' && !quoted) {
3137                                 int keyword = GetKeyword (id_builder, pos);
3138                                 if (keyword != -1) {
3139                                         val = ltb.Create (keyword == Token.AWAIT ? "await" : null, current_source, ref_line, column);
3140                                         return keyword;
3141                                 }
3142                         }
3143
3144                         string s = InternIdentifier (id_builder, pos);
3145                         val = ltb.Create (s, current_source, ref_line, column);
3146                         if (quoted && parsing_attribute_section)
3147                                 AddEscapedIdentifier (((LocatedToken) val).Location);
3148
3149                         return Token.IDENTIFIER;
3150                 }
3151
3152                 string InternIdentifier (char[] charBuffer, int length)
3153                 {
3154                         //
3155                         // Keep identifiers in an array of hashtables to avoid needless
3156                         // allocations
3157                         //
3158                         var identifiers_group = identifiers[length];
3159                         string s;
3160                         if (identifiers_group != null) {
3161                                 if (identifiers_group.TryGetValue (charBuffer, out s)) {
3162                                         return s;
3163                                 }
3164                         } else {
3165                                 // TODO: this should be number of files dependant
3166                                 // corlib compilation peaks at 1000 and System.Core at 150
3167                                 int capacity = length > 20 ? 10 : 100;
3168                                 identifiers_group = new Dictionary<char[], string> (capacity, new IdentifiersComparer (length));
3169                                 identifiers[length] = identifiers_group;
3170                         }
3171
3172                         char[] chars = new char[length];
3173                         Array.Copy (charBuffer, chars, length);
3174
3175                         s = new string (charBuffer, 0, length);
3176                         identifiers_group.Add (chars, s);
3177                         return s;
3178                 }
3179
3180                 public int xtoken ()
3181                 {
3182                         int d, c;
3183
3184                         // Whether we have seen comments on the current line
3185                         bool comments_seen = false;
3186                         while ((c = get_char ()) != -1) {
3187                                 switch (c) {
3188                                 case '\t':
3189                                         col = ((col - 1 + tab_size) / tab_size) * tab_size;
3190                                         continue;
3191
3192                                 case ' ':
3193                                 case '\f':
3194                                 case '\v':
3195                                 case 0xa0:
3196                                 case 0:
3197                                 case 0xFEFF:    // Ignore BOM anywhere in the file
3198                                         continue;
3199
3200 /*                              This is required for compatibility with .NET
3201                                 case 0xEF:
3202                                         if (peek_char () == 0xBB) {
3203                                                 PushPosition ();
3204                                                 get_char ();
3205                                                 if (get_char () == 0xBF)
3206                                                         continue;
3207                                                 PopPosition ();
3208                                         }
3209                                         break;
3210 */
3211                                 case '\\':
3212                                         tokens_seen = true;
3213                                         return consume_identifier (c);
3214
3215                                 case '{':
3216                                         val = ltb.Create (current_source, ref_line, col);
3217                                         return Token.OPEN_BRACE;
3218                                 case '}':
3219                                         val = ltb.Create (current_source, ref_line, col);
3220                                         return Token.CLOSE_BRACE;
3221                                 case '[':
3222                                         // To block doccomment inside attribute declaration.
3223                                         if (doc_state == XmlCommentState.Allowed)
3224                                                 doc_state = XmlCommentState.NotAllowed;
3225
3226                                         val = ltb.Create (current_source, ref_line, col);
3227
3228                                         if (parsing_block == 0 || lambda_arguments_parsing)
3229                                                 return Token.OPEN_BRACKET;
3230
3231                                         int next = peek_char ();
3232                                         switch (next) {
3233                                         case ']':
3234                                         case ',':
3235                                                 return Token.OPEN_BRACKET;
3236
3237                                         case ' ':
3238                                         case '\f':
3239                                         case '\v':
3240                                         case '\r':
3241                                         case '\n':
3242                                         case UnicodeLS:
3243                                         case UnicodePS:
3244                                         case '/':
3245                                                 next = peek_token ();
3246                                                 if (next == Token.COMMA || next == Token.CLOSE_BRACKET)
3247                                                         return Token.OPEN_BRACKET;
3248
3249                                                 return Token.OPEN_BRACKET_EXPR;
3250                                         default:
3251                                                 return Token.OPEN_BRACKET_EXPR;
3252                                         }
3253                                 case ']':
3254                                         ltb.CreateOptional (current_source, ref_line, col, ref val);
3255                                         return Token.CLOSE_BRACKET;
3256                                 case '(':
3257                                         val = ltb.Create (current_source, ref_line, col);
3258                                         //
3259                                         // An expression versions of parens can appear in block context only
3260                                         //
3261                                         if (parsing_block != 0 && !lambda_arguments_parsing) {
3262
3263                                                 //
3264                                                 // Optmize most common case where we know that parens
3265                                                 // is not special
3266                                                 //
3267                                                 switch (current_token) {
3268                                                 case Token.IDENTIFIER:
3269                                                 case Token.IF:
3270                                                 case Token.FOR:
3271                                                 case Token.FOREACH:
3272                                                 case Token.TYPEOF:
3273                                                 case Token.WHILE:
3274                                                 case Token.SWITCH:
3275                                                 case Token.USING:
3276                                                 case Token.DEFAULT:
3277                                                 case Token.DELEGATE:
3278                                                 case Token.OP_GENERICS_GT:
3279                                                         return Token.OPEN_PARENS;
3280                                                 }
3281
3282                                                 // Optimize using peek
3283                                                 int xx = peek_char ();
3284                                                 switch (xx) {
3285                                                 case '(':
3286                                                 case '\'':
3287                                                 case '"':
3288                                                 case '0':
3289                                                 case '1':
3290                                                         return Token.OPEN_PARENS;
3291                                                 }
3292
3293                                                 lambda_arguments_parsing = true;
3294                                                 PushPosition ();
3295                                                 d = TokenizeOpenParens ();
3296                                                 PopPosition ();
3297                                                 lambda_arguments_parsing = false;
3298                                                 return d;
3299                                         }
3300
3301                                         return Token.OPEN_PARENS;
3302                                 case ')':
3303                                         ltb.CreateOptional (current_source, ref_line, col, ref val);
3304                                         return Token.CLOSE_PARENS;
3305                                 case ',':
3306                                         ltb.CreateOptional (current_source, ref_line, col, ref val);
3307                                         return Token.COMMA;
3308                                 case ';':
3309                                         ltb.CreateOptional (current_source, ref_line, col, ref val);
3310                                         return Token.SEMICOLON;
3311                                 case '~':
3312                                         val = ltb.Create (current_source, ref_line, col);
3313                                         return Token.TILDE;
3314                                 case '?':
3315                                         val = ltb.Create (current_source, ref_line, col);
3316                                         return TokenizePossibleNullableType ();
3317                                 case '<':
3318                                         val = ltb.Create (current_source, ref_line, col);
3319                                         if (parsing_generic_less_than++ > 0)
3320                                                 return Token.OP_GENERICS_LT;
3321
3322                                         return TokenizeLessThan ();
3323
3324                                 case '>':
3325                                         val = ltb.Create (current_source, ref_line, col);
3326                                         d = peek_char ();
3327
3328                                         if (d == '='){
3329                                                 get_char ();
3330                                                 return Token.OP_GE;
3331                                         }
3332
3333                                         if (parsing_generic_less_than > 1 || (parsing_generic_less_than == 1 && d != '>')) {
3334                                                 parsing_generic_less_than--;
3335                                                 return Token.OP_GENERICS_GT;
3336                                         }
3337
3338                                         if (d == '>') {
3339                                                 get_char ();
3340                                                 d = peek_char ();
3341
3342                                                 if (d == '=') {
3343                                                         get_char ();
3344                                                         return Token.OP_SHIFT_RIGHT_ASSIGN;
3345                                                 }
3346                                                 return Token.OP_SHIFT_RIGHT;
3347                                         }
3348
3349                                         return Token.OP_GT;
3350
3351                                 case '+':
3352                                         val = ltb.Create (current_source, ref_line, col);
3353                                         d = peek_char ();
3354                                         if (d == '+') {
3355                                                 d = Token.OP_INC;
3356                                         } else if (d == '=') {
3357                                                 d = Token.OP_ADD_ASSIGN;
3358                                         } else {
3359                                                 return Token.PLUS;
3360                                         }
3361                                         get_char ();
3362                                         return d;
3363
3364                                 case '-':
3365                                         val = ltb.Create (current_source, ref_line, col);
3366                                         d = peek_char ();
3367                                         if (d == '-') {
3368                                                 d = Token.OP_DEC;
3369                                         } else if (d == '=')
3370                                                 d = Token.OP_SUB_ASSIGN;
3371                                         else if (d == '>')
3372                                                 d = Token.OP_PTR;
3373                                         else {
3374                                                 return Token.MINUS;
3375                                         }
3376                                         get_char ();
3377                                         return d;
3378
3379                                 case '!':
3380                                         val = ltb.Create (current_source, ref_line, col);
3381                                         if (peek_char () == '='){
3382                                                 get_char ();
3383                                                 return Token.OP_NE;
3384                                         }
3385                                         return Token.BANG;
3386
3387                                 case '=':
3388                                         val = ltb.Create (current_source, ref_line, col);
3389                                         d = peek_char ();
3390                                         if (d == '='){
3391                                                 get_char ();
3392                                                 return Token.OP_EQ;
3393                                         }
3394                                         if (d == '>'){
3395                                                 get_char ();
3396                                                 return Token.ARROW;
3397                                         }
3398
3399                                         return Token.ASSIGN;
3400
3401                                 case '&':
3402                                         val = ltb.Create (current_source, ref_line, col);
3403                                         d = peek_char ();
3404                                         if (d == '&'){
3405                                                 get_char ();
3406                                                 return Token.OP_AND;
3407                                         }
3408                                         if (d == '='){
3409                                                 get_char ();
3410                                                 return Token.OP_AND_ASSIGN;
3411                                         }
3412                                         return Token.BITWISE_AND;
3413
3414                                 case '|':
3415                                         val = ltb.Create (current_source, ref_line, col);
3416                                         d = peek_char ();
3417                                         if (d == '|'){
3418                                                 get_char ();
3419                                                 return Token.OP_OR;
3420                                         }
3421                                         if (d == '='){
3422                                                 get_char ();
3423                                                 return Token.OP_OR_ASSIGN;
3424                                         }
3425                                         return Token.BITWISE_OR;
3426
3427                                 case '*':
3428                                         val = ltb.Create (current_source, ref_line, col);
3429                                         if (peek_char () == '='){
3430                                                 get_char ();
3431                                                 return Token.OP_MULT_ASSIGN;
3432                                         }
3433                                         return Token.STAR;
3434
3435                                 case '/':
3436                                         d = peek_char ();
3437                                         if (d == '='){
3438                                                 val = ltb.Create (current_source, ref_line, col);
3439                                                 get_char ();
3440                                                 return Token.OP_DIV_ASSIGN;
3441                                         }
3442
3443                                         // Handle double-slash comments.
3444                                         if (d == '/'){
3445                                                 get_char ();
3446                                                 if (doc_processing) {
3447                                                         if (peek_char () == '/') {
3448                                                                 get_char ();
3449                                                                 // Don't allow ////.
3450                                                                 if ((d = peek_char ()) != '/') {
3451                                                                         if (doc_state == XmlCommentState.Allowed)
3452                                                                                 handle_one_line_xml_comment ();
3453                                                                         else if (doc_state == XmlCommentState.NotAllowed)
3454                                                                                 WarningMisplacedComment (Location - 3);
3455                                                                 }
3456                                                         } else {
3457                                                                 if (xml_comment_buffer.Length > 0)
3458                                                                         doc_state = XmlCommentState.NotAllowed;
3459                                                         }
3460                                                 }
3461
3462                                                 ReadToEndOfLine ();
3463
3464                                                 any_token_seen |= tokens_seen;
3465                                                 tokens_seen = false;
3466                                                 comments_seen = false;
3467                                                 continue;
3468                                         } else if (d == '*'){
3469                                                 get_char ();
3470                                                 bool docAppend = false;
3471                                                 if (doc_processing && peek_char () == '*') {
3472                                                         get_char ();
3473                                                         // But when it is /**/, just do nothing.
3474                                                         if (peek_char () == '/') {
3475                                                                 get_char ();
3476                                                                 continue;
3477                                                         }
3478                                                         if (doc_state == XmlCommentState.Allowed)
3479                                                                 docAppend = true;
3480                                                         else if (doc_state == XmlCommentState.NotAllowed) {
3481                                                                 WarningMisplacedComment (Location - 2);
3482                                                         }
3483                                                 }
3484
3485                                                 int current_comment_start = 0;
3486                                                 if (docAppend) {
3487                                                         current_comment_start = xml_comment_buffer.Length;
3488                                                         xml_comment_buffer.Append (Environment.NewLine);
3489                                                 }
3490
3491                                                 while ((d = get_char ()) != -1){
3492                                                         if (d == '*' && peek_char () == '/'){
3493                                                                 get_char ();
3494                                                                 comments_seen = true;
3495                                                                 break;
3496                                                         }
3497                                                         if (docAppend)
3498                                                                 xml_comment_buffer.Append ((char) d);
3499
3500                                                         if (d == '\n' || d == UnicodeLS || d == UnicodePS){
3501                                                                 any_token_seen |= tokens_seen;
3502                                                                 tokens_seen = false;
3503                                                                 //
3504                                                                 // Reset 'comments_seen' just to be consistent.
3505                                                                 // It doesn't matter either way, here.
3506                                                                 //
3507                                                                 comments_seen = false;
3508                                                         }
3509                                                 }
3510                                                 if (!comments_seen)
3511                                                         Report.Error (1035, Location, "End-of-file found, '*/' expected");
3512
3513                                                 if (docAppend)
3514                                                         update_formatted_doc_comment (current_comment_start);
3515                                                 continue;
3516                                         }
3517                                         val = ltb.Create (current_source, ref_line, col);
3518                                         return Token.DIV;
3519
3520                                 case '%':
3521                                         val = ltb.Create (current_source, ref_line, col);
3522                                         if (peek_char () == '='){
3523                                                 get_char ();
3524                                                 return Token.OP_MOD_ASSIGN;
3525                                         }
3526                                         return Token.PERCENT;
3527
3528                                 case '^':
3529                                         val = ltb.Create (current_source, ref_line, col);
3530                                         if (peek_char () == '='){
3531                                                 get_char ();
3532                                                 return Token.OP_XOR_ASSIGN;
3533                                         }
3534                                         return Token.CARRET;
3535
3536                                 case ':':
3537                                         val = ltb.Create (current_source, ref_line, col);
3538                                         if (peek_char () == ':') {
3539                                                 get_char ();
3540                                                 return Token.DOUBLE_COLON;
3541                                         }
3542                                         return Token.COLON;
3543
3544                                 case '0': case '1': case '2': case '3': case '4':
3545                                 case '5': case '6': case '7': case '8': case '9':
3546                                         tokens_seen = true;
3547                                         return is_number (c, false);
3548
3549                                 case '\n': // white space
3550                                 case UnicodeLS:
3551                                 case UnicodePS:
3552                                         any_token_seen |= tokens_seen;
3553                                         tokens_seen = false;
3554                                         comments_seen = false;
3555                                         continue;
3556
3557                                 case '.':
3558                                         tokens_seen = true;
3559                                         d = peek_char ();
3560                                         if (d >= '0' && d <= '9')
3561                                                 return is_number (c, true);
3562
3563                                         ltb.CreateOptional (current_source, ref_line, col, ref val);
3564                                         return Token.DOT;
3565
3566                                 case '#':
3567                                         if (tokens_seen || comments_seen) {
3568                                                 Eror_WrongPreprocessorLocation ();
3569                                                 return Token.ERROR;
3570                                         }
3571
3572                                         if (ParsePreprocessingDirective (true))
3573                                                 continue;
3574
3575                                         bool directive_expected = false;
3576                                         while ((c = get_char ()) != -1) {
3577                                                 if (col == 1) {
3578                                                         directive_expected = true;
3579                                                 } else if (!directive_expected) {
3580                                                         // TODO: Implement comment support for disabled code and uncomment this code
3581 //                                                      if (c == '#') {
3582 //                                                              Eror_WrongPreprocessorLocation ();
3583 //                                                              return Token.ERROR;
3584 //                                                      }
3585                                                         continue;
3586                                                 }
3587
3588                                                 if (c == ' ' || c == '\t' || c == '\n' || c == '\f' || c == '\v' || c == UnicodeLS || c == UnicodePS)
3589                                                         continue;
3590
3591                                                 if (c == '#') {
3592                                                         if (ParsePreprocessingDirective (false))
3593                                                                 break;
3594                                                 }
3595                                                 directive_expected = false;
3596                                         }
3597
3598                                         if (c != -1) {
3599                                                 tokens_seen = false;
3600                                                 continue;
3601                                         }
3602
3603                                         return Token.EOF;
3604
3605                                 case '"':
3606                                         return consume_string (false);
3607
3608                                 case '\'':
3609                                         return TokenizeBackslash ();
3610
3611                                 case '@':
3612                                         c = get_char ();
3613                                         if (c == '"') {
3614                                                 tokens_seen = true;
3615                                                 return consume_string (true);
3616                                         }
3617
3618                                         if (is_identifier_start_character (c)){
3619                                                 return consume_identifier (c, true);
3620                                         }
3621
3622                                         Report.Error (1646, Location, "Keyword, identifier, or string expected after verbatim specifier: @");
3623                                         return Token.ERROR;
3624
3625                                 case EvalStatementParserCharacter:
3626                                         return Token.EVAL_STATEMENT_PARSER;
3627                                 case EvalCompilationUnitParserCharacter:
3628                                         return Token.EVAL_COMPILATION_UNIT_PARSER;
3629                                 case EvalUsingDeclarationsParserCharacter:
3630                                         return Token.EVAL_USING_DECLARATIONS_UNIT_PARSER;
3631                                 case DocumentationXref:
3632                                         return Token.DOC_SEE;
3633                                 }
3634
3635                                 if (is_identifier_start_character (c)) {
3636                                         tokens_seen = true;
3637                                         return consume_identifier (c);
3638                                 }
3639
3640                                 if (char.IsWhiteSpace ((char) c))
3641                                         continue;
3642
3643                                 Report.Error (1056, Location, "Unexpected character `{0}'", ((char) c).ToString ());
3644                         }
3645
3646                         if (CompleteOnEOF){
3647                                 if (generated)
3648                                         return Token.COMPLETE_COMPLETION;
3649
3650                                 generated = true;
3651                                 return Token.GENERATE_COMPLETION;
3652                         }
3653
3654
3655                         return Token.EOF;
3656                 }
3657
3658                 int TokenizeBackslash ()
3659                 {
3660 #if FULL_AST
3661                         int read_start = reader.Position;
3662 #endif
3663                         Location start_location = Location;
3664                         int c = get_char ();
3665                         tokens_seen = true;
3666                         if (c == '\'') {
3667                                 val = new CharLiteral (context.BuiltinTypes, (char) c, start_location);
3668                                 Report.Error (1011, start_location, "Empty character literal");
3669                                 return Token.LITERAL;
3670                         }
3671
3672                         if (c == '\n' || c == UnicodeLS || c == UnicodePS) {
3673                                 Report.Error (1010, start_location, "Newline in constant");
3674                                 return Token.ERROR;
3675                         }
3676
3677                         int d;
3678                         c = escape (c, out d);
3679                         if (c == -1)
3680                                 return Token.ERROR;
3681                         if (d != 0)
3682                                 throw new NotImplementedException ();
3683
3684                         ILiteralConstant res = new CharLiteral (context.BuiltinTypes, (char) c, start_location);
3685                         val = res;
3686                         c = get_char ();
3687
3688                         if (c != '\'') {
3689                                 Report.Error (1012, start_location, "Too many characters in character literal");
3690
3691                                 // Try to recover, read until newline or next "'"
3692                                 while ((c = get_char ()) != -1) {
3693                                         if (c == '\n' || c == '\'' || c == UnicodeLS || c == UnicodePS)
3694                                                 break;
3695                                 }
3696                         }
3697
3698 #if FULL_AST
3699                         res.ParsedValue = reader.ReadChars (read_start - 1, reader.Position);
3700 #endif
3701
3702                         return Token.LITERAL;
3703                 }
3704
3705                 int TokenizeLessThan ()
3706                 {
3707                         int d;
3708
3709                         // Save current position and parse next token.
3710                         PushPosition ();
3711                         int generic_dimension = 0;
3712                         if (parse_less_than (ref generic_dimension)) {
3713                                 if (parsing_generic_declaration && (parsing_generic_declaration_doc || token () != Token.DOT)) {
3714                                         d = Token.OP_GENERICS_LT_DECL;
3715                                 } else {
3716                                         if (generic_dimension > 0) {
3717                                                 val = generic_dimension;
3718                                                 DiscardPosition ();
3719                                                 return Token.GENERIC_DIMENSION;
3720                                         }
3721
3722                                         d = Token.OP_GENERICS_LT;
3723                                 }
3724                                 PopPosition ();
3725                                 return d;
3726                         }
3727
3728                         PopPosition ();
3729                         parsing_generic_less_than = 0;
3730
3731                         d = peek_char ();
3732                         if (d == '<') {
3733                                 get_char ();
3734                                 d = peek_char ();
3735
3736                                 if (d == '=') {
3737                                         get_char ();
3738                                         return Token.OP_SHIFT_LEFT_ASSIGN;
3739                                 }
3740                                 return Token.OP_SHIFT_LEFT;
3741                         }
3742
3743                         if (d == '=') {
3744                                 get_char ();
3745                                 return Token.OP_LE;
3746                         }
3747                         return Token.OP_LT;
3748                 }
3749
3750                 //
3751                 // Handles one line xml comment
3752                 //
3753                 private void handle_one_line_xml_comment ()
3754                 {
3755                         int c;
3756                         while ((c = peek_char ()) == ' ')
3757                                 get_char (); // skip heading whitespaces.
3758                         while ((c = peek_char ()) != -1 && c != '\n' && c != '\r') {
3759                                 xml_comment_buffer.Append ((char) get_char ());
3760                         }
3761                         if (c == '\r' || c == '\n')
3762                                 xml_comment_buffer.Append (Environment.NewLine);
3763                 }
3764
3765                 //
3766                 // Remove heading "*" in Javadoc-like xml documentation.
3767                 //
3768                 private void update_formatted_doc_comment (int current_comment_start)
3769                 {
3770                         int length = xml_comment_buffer.Length - current_comment_start;
3771                         string [] lines = xml_comment_buffer.ToString (
3772                                 current_comment_start,
3773                                 length).Replace ("\r", "").Split ('\n');
3774
3775                         // The first line starts with /**, thus it is not target
3776                         // for the format check.
3777                         for (int i = 1; i < lines.Length; i++) {
3778                                 string s = lines [i];
3779                                 int idx = s.IndexOf ('*');
3780                                 string head = null;
3781                                 if (idx < 0) {
3782                                         if (i < lines.Length - 1)
3783                                                 return;
3784                                         head = s;
3785                                 } else
3786                                         head = s.Substring (0, idx);
3787                                 foreach (char c in head)
3788                                         if (c != ' ')
3789                                                 return;
3790                                 lines [i] = s.Substring (idx + 1);
3791                         }
3792                         xml_comment_buffer.Remove (current_comment_start, length);
3793                         xml_comment_buffer.Insert (current_comment_start, String.Join (Environment.NewLine, lines));
3794                 }
3795
3796                 //
3797                 // Checks if there was incorrect doc comments and raise
3798                 // warnings.
3799                 //
3800                 public void check_incorrect_doc_comment ()
3801                 {
3802                         if (xml_comment_buffer.Length > 0)
3803                                 WarningMisplacedComment (Location);
3804                 }
3805
3806                 //
3807                 // Consumes the saved xml comment lines (if any)
3808                 // as for current target member or type.
3809                 //
3810                 public string consume_doc_comment ()
3811                 {
3812                         if (xml_comment_buffer.Length > 0) {
3813                                 string ret = xml_comment_buffer.ToString ();
3814                                 reset_doc_comment ();
3815                                 return ret;
3816                         }
3817                         return null;
3818                 }
3819
3820                 void reset_doc_comment ()
3821                 {
3822                         xml_comment_buffer.Length = 0;
3823                 }
3824
3825                 public void cleanup ()
3826                 {
3827                         if (ifstack != null && ifstack.Count >= 1) {
3828                                 int state = ifstack.Pop ();
3829                                 if ((state & REGION) != 0)
3830                                         Report.Error (1038, Location, "#endregion directive expected");
3831                                 else
3832                                         Report.Error (1027, Location, "Expected `#endif' directive");
3833                         }
3834                 }
3835         }
3836
3837         //
3838         // Indicates whether it accepts XML documentation or not.
3839         //
3840         public enum XmlCommentState {
3841                 // comment is allowed in this state.
3842                 Allowed,
3843                 // comment is not allowed in this state.
3844                 NotAllowed,
3845                 // once comments appeared when it is NotAllowed, then the
3846                 // state is changed to it, until the state is changed to
3847                 // .Allowed.
3848                 Error
3849         }
3850 }
3851