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@seznam.cz)
   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 //
  13 //
  14
  15 using System;
  16 using System.Text;
  17 using System.Collections;
  18 using System.IO;
  19 using System.Globalization;
  20 using System.Reflection;
  21
  22 namespace Mono.CSharp
  23 {
  24         /// <summary>
  25         ///    Tokenizer for C# source code.
  26         /// </summary>
  27
  28         public class Tokenizer : yyParser.yyInput
  29         {
  30                 SeekableStreamReader reader;
  31                 SourceFile ref_name;
  32                 CompilationUnit file_name;
  33                 bool hidden = false;
  34                 int ref_line = 1;
  35                 int line = 1;
  36                 int col = 0;
  37                 int previous_col;
  38                 int current_token;
  39                 bool handle_get_set = false;
  40                 bool handle_remove_add = false;
  41                 bool handle_assembly = false;
  42                 bool handle_where = false;
  43                 bool handle_typeof = false;
  44                 bool lambda_arguments_parsing;
  45                 Location current_location;
  46                 Location current_comment_location = Location.Null;
  47                 ArrayList escaped_identifiers = new ArrayList ();
  48                 public int parsing_block;
  49                 internal int query_parsing;
  50
  51                 //
  52                 // XML documentation buffer. The save point is used to divide
  53                 // comments on types and comments on members.
  54                 //
  55                 StringBuilder xml_comment_buffer;
  56
  57                 //
  58                 // See comment on XmlCommentState enumeration.
  59                 //
  60                 XmlCommentState xml_doc_state = XmlCommentState.Allowed;
  61
  62                 //
  63                 // Whether tokens have been seen on this line
  64                 //
  65                 bool tokens_seen = false;
  66
  67                 //
  68                 // Whether a token has been seen on the file
  69                 // This is needed because `define' is not allowed to be used
  70                 // after a token has been seen.
  71                 //
  72                 bool any_token_seen = false;
  73
  74                 static Hashtable token_values;
  75                 static readonly char[] simple_whitespaces = new char[] { ' ', '\t' };
  76
  77                 private static Hashtable TokenValueName
  78                 {
  79                         get {
  80                                 if (token_values == null)
  81                                         token_values = GetTokenValueNameHash ();
  82
  83                                 return token_values;
  84                         }
  85                 }
  86
  87                 private static Hashtable GetTokenValueNameHash ()
  88                 {
  89                         Type t = typeof (Token);
  90                         FieldInfo [] fields = t.GetFields ();
  91                         Hashtable hash = new Hashtable ();
  92                         foreach (FieldInfo field in fields) {
  93                                 if (field.IsLiteral && field.IsStatic && field.FieldType == typeof (int))
  94                                         hash.Add (field.GetValue (null), field.Name);
  95                         }
  96                         return hash;
  97                 }
  98
  99                 //
 100                 // Returns a verbose representation of the current location
 101                 //
 102                 public string location {
 103                         get {
 104                                 string det;
 105
 106                                 if (current_token == Token.ERROR)
 107                                         det = "detail: " + error_details;
 108                                 else
 109                                         det = "";
 110
 111                                 // return "Line:     "+line+" Col: "+col + "\n" +
 112                                 //       "VirtLine: "+ref_line +
 113                                 //       " Token: "+current_token + " " + det;
 114                                 string current_token_name = TokenValueName [current_token] as string;
 115                                 if (current_token_name == null)
 116                                         current_token_name = current_token.ToString ();
 117
 118                                 return String.Format ("{0} ({1},{2}), Token: {3} {4}", ref_name.Name,
 119                                                                                        ref_line,
 120                                                                                        col,
 121                                                                                        current_token_name,
 122                                                                                        det);
 123                         }
 124                 }
 125
 126                 public bool PropertyParsing {
 127                         get { return handle_get_set; }
 128                         set { handle_get_set = value; }
 129                 }
 130
 131                 public bool AssemblyTargetParsing {
 132                         get { return handle_assembly; }
 133                         set { handle_assembly = value; }
 134                 }
 135
 136                 public bool EventParsing {
 137                         get { return handle_remove_add; }
 138                         set { handle_remove_add = value; }
 139                 }
 140
 141                 public bool ConstraintsParsing {
 142                         get { return handle_where; }
 143                         set { handle_where = value; }
 144                 }
 145
 146                 public bool TypeOfParsing {
 147                         get { return handle_typeof; }
 148                         set { handle_typeof = value; }
 149                 }
 150
 151                 public XmlCommentState doc_state {
 152                         get { return xml_doc_state; }
 153                         set {
 154                                 if (value == XmlCommentState.Allowed) {
 155                                         check_incorrect_doc_comment ();
 156                                         reset_doc_comment ();
 157                                 }
 158                                 xml_doc_state = value;
 159                         }
 160                 }
 161
 162                 public bool IsEscapedIdentifier (Location loc)
 163                 {
 164                         foreach (LocatedToken lt in escaped_identifiers)
 165                                 if (lt.Location.Equals (loc))
 166                                         return true;
 167                         return false;
 168                 }
 169
 170                 //
 171                 // Class variables
 172                 //
 173                 static CharArrayHashtable[] keywords;
 174                 static Hashtable keyword_strings;
 175                 static NumberStyles styles;
 176                 static NumberFormatInfo csharp_format_info;
 177
 178                 //
 179                 // Values for the associated token returned
 180                 //
 181                 int putback_char;
 182                 Object val;
 183
 184                 //
 185                 // Pre-processor
 186                 //
 187                 const int TAKING        = 1;
 188                 const int ELSE_SEEN     = 4;
 189                 const int PARENT_TAKING = 8;
 190                 const int REGION        = 16;
 191
 192                 //
 193                 // pre-processor if stack state:
 194                 //
 195                 Stack ifstack;
 196
 197                 static System.Text.StringBuilder string_builder;
 198
 199                 const int max_id_size = 512;
 200                 static char [] id_builder = new char [max_id_size];
 201
 202                 static CharArrayHashtable [] identifiers = new CharArrayHashtable [max_id_size + 1];
 203
 204                 const int max_number_size = 512;
 205                 static char [] number_builder = new char [max_number_size];
 206                 static int number_pos;
 207
 208                 //
 209                 // Details about the error encoutered by the tokenizer
 210                 //
 211                 string error_details;
 212
 213                 public string error {
 214                         get {
 215                                 return error_details;
 216                         }
 217                 }
 218
 219                 public int Line {
 220                         get {
 221                                 return ref_line;
 222                         }
 223                 }
 224
 225                 public int Col {
 226                         get {
 227                                 return col;
 228                         }
 229                 }
 230
 231                 //
 232                 // This is used when the tokenizer needs to save
 233                 // the current position as it needs to do some parsing
 234                 // on its own to deamiguate a token in behalf of the
 235                 // parser.
 236                 //
 237                 Stack position_stack = new Stack (2);
 238                 class Position {
 239                         public int position;
 240                         public int line;
 241                         public int ref_line;
 242                         public int col;
 243                         public bool hidden;
 244                         public int putback_char;
 245                         public int previous_col;
 246                         public Stack ifstack;
 247                         public int parsing_generic_less_than;
 248                         public int current_token;
 249
 250                         public Position (Tokenizer t)
 251                         {
 252                                 position = t.reader.Position;
 253                                 line = t.line;
 254                                 ref_line = t.ref_line;
 255                                 col = t.col;
 256                                 hidden = t.hidden;
 257                                 putback_char = t.putback_char;
 258                                 previous_col = t.previous_col;
 259                                 if (t.ifstack != null && t.ifstack.Count != 0)
 260                                         ifstack = (Stack)t.ifstack.Clone ();
 261                                 parsing_generic_less_than = t.parsing_generic_less_than;
 262                                 current_token = t.current_token;
 263                         }
 264                 }
 265
 266                 public void PushPosition ()
 267                 {
 268                         position_stack.Push (new Position (this));
 269                 }
 270
 271                 public void PopPosition ()
 272                 {
 273                         Position p = (Position) position_stack.Pop ();
 274
 275                         reader.Position = p.position;
 276                         ref_line = p.ref_line;
 277                         line = p.line;
 278                         col = p.col;
 279                         hidden = p.hidden;
 280                         putback_char = p.putback_char;
 281                         previous_col = p.previous_col;
 282                         ifstack = p.ifstack;
 283                         parsing_generic_less_than = p.parsing_generic_less_than;
 284                         current_token = p.current_token;
 285                 }
 286
 287                 // Do not reset the position, ignore it.
 288                 public void DiscardPosition ()
 289                 {
 290                         position_stack.Pop ();
 291                 }
 292
 293                 static void AddKeyword (string kw, int token)
 294                 {
 295                         keyword_strings.Add (kw, kw);
 296                         if (keywords [kw.Length] == null) {
 297                                 keywords [kw.Length] = new CharArrayHashtable (kw.Length);
 298                         }
 299                         keywords [kw.Length] [kw.ToCharArray ()] = token;
 300                 }
 301
 302                 static void InitTokens ()
 303                 {
 304                         keyword_strings = new Hashtable ();
 305                         keywords = new CharArrayHashtable [64];
 306
 307                         AddKeyword ("__arglist", Token.ARGLIST);
 308                         AddKeyword ("abstract", Token.ABSTRACT);
 309                         AddKeyword ("as", Token.AS);
 310                         AddKeyword ("add", Token.ADD);
 311                         AddKeyword ("assembly", Token.ASSEMBLY);
 312                         AddKeyword ("base", Token.BASE);
 313                         AddKeyword ("bool", Token.BOOL);
 314                         AddKeyword ("break", Token.BREAK);
 315                         AddKeyword ("byte", Token.BYTE);
 316                         AddKeyword ("case", Token.CASE);
 317                         AddKeyword ("catch", Token.CATCH);
 318                         AddKeyword ("char", Token.CHAR);
 319                         AddKeyword ("checked", Token.CHECKED);
 320                         AddKeyword ("class", Token.CLASS);
 321                         AddKeyword ("const", Token.CONST);
 322                         AddKeyword ("continue", Token.CONTINUE);
 323                         AddKeyword ("decimal", Token.DECIMAL);
 324                         AddKeyword ("default", Token.DEFAULT);
 325                         AddKeyword ("delegate", Token.DELEGATE);
 326                         AddKeyword ("do", Token.DO);
 327                         AddKeyword ("double", Token.DOUBLE);
 328                         AddKeyword ("else", Token.ELSE);
 329                         AddKeyword ("enum", Token.ENUM);
 330                         AddKeyword ("event", Token.EVENT);
 331                         AddKeyword ("explicit", Token.EXPLICIT);
 332                         AddKeyword ("extern", Token.EXTERN);
 333                         AddKeyword ("false", Token.FALSE);
 334                         AddKeyword ("finally", Token.FINALLY);
 335                         AddKeyword ("fixed", Token.FIXED);
 336                         AddKeyword ("float", Token.FLOAT);
 337                         AddKeyword ("for", Token.FOR);
 338                         AddKeyword ("foreach", Token.FOREACH);
 339                         AddKeyword ("goto", Token.GOTO);
 340                         AddKeyword ("get", Token.GET);
 341                         AddKeyword ("if", Token.IF);
 342                         AddKeyword ("implicit", Token.IMPLICIT);
 343                         AddKeyword ("in", Token.IN);
 344                         AddKeyword ("int", Token.INT);
 345                         AddKeyword ("interface", Token.INTERFACE);
 346                         AddKeyword ("internal", Token.INTERNAL);
 347                         AddKeyword ("is", Token.IS);
 348                         AddKeyword ("lock", Token.LOCK);
 349                         AddKeyword ("long", Token.LONG);
 350                         AddKeyword ("namespace", Token.NAMESPACE);
 351                         AddKeyword ("new", Token.NEW);
 352                         AddKeyword ("null", Token.NULL);
 353                         AddKeyword ("object", Token.OBJECT);
 354                         AddKeyword ("operator", Token.OPERATOR);
 355                         AddKeyword ("out", Token.OUT);
 356                         AddKeyword ("override", Token.OVERRIDE);
 357                         AddKeyword ("params", Token.PARAMS);
 358                         AddKeyword ("private", Token.PRIVATE);
 359                         AddKeyword ("protected", Token.PROTECTED);
 360                         AddKeyword ("public", Token.PUBLIC);
 361                         AddKeyword ("readonly", Token.READONLY);
 362                         AddKeyword ("ref", Token.REF);
 363                         AddKeyword ("remove", Token.REMOVE);
 364                         AddKeyword ("return", Token.RETURN);
 365                         AddKeyword ("sbyte", Token.SBYTE);
 366                         AddKeyword ("sealed", Token.SEALED);
 367                         AddKeyword ("set", Token.SET);
 368                         AddKeyword ("short", Token.SHORT);
 369                         AddKeyword ("sizeof", Token.SIZEOF);
 370                         AddKeyword ("stackalloc", Token.STACKALLOC);
 371                         AddKeyword ("static", Token.STATIC);
 372                         AddKeyword ("string", Token.STRING);
 373                         AddKeyword ("struct", Token.STRUCT);
 374                         AddKeyword ("switch", Token.SWITCH);
 375                         AddKeyword ("this", Token.THIS);
 376                         AddKeyword ("throw", Token.THROW);
 377                         AddKeyword ("true", Token.TRUE);
 378                         AddKeyword ("try", Token.TRY);
 379                         AddKeyword ("typeof", Token.TYPEOF);
 380                         AddKeyword ("uint", Token.UINT);
 381                         AddKeyword ("ulong", Token.ULONG);
 382                         AddKeyword ("unchecked", Token.UNCHECKED);
 383                         AddKeyword ("unsafe", Token.UNSAFE);
 384                         AddKeyword ("ushort", Token.USHORT);
 385                         AddKeyword ("using", Token.USING);
 386                         AddKeyword ("virtual", Token.VIRTUAL);
 387                         AddKeyword ("void", Token.VOID);
 388                         AddKeyword ("volatile", Token.VOLATILE);
 389                         AddKeyword ("while", Token.WHILE);
 390                         AddKeyword ("partial", Token.PARTIAL);
 391                         AddKeyword ("where", Token.WHERE);
 392
 393                         // LINQ keywords
 394                         AddKeyword ("from", Token.FROM);
 395                         AddKeyword ("join", Token.JOIN);
 396                         AddKeyword ("on", Token.ON);
 397                         AddKeyword ("equals", Token.EQUALS);
 398                         AddKeyword ("select", Token.SELECT);
 399                         AddKeyword ("group", Token.GROUP);
 400                         AddKeyword ("by", Token.BY);
 401                         AddKeyword ("let", Token.LET);
 402                         AddKeyword ("orderby", Token.ORDERBY);
 403                         AddKeyword ("ascending", Token.ASCENDING);
 404                         AddKeyword ("descending", Token.DESCENDING);
 405                         AddKeyword ("into", Token.INTO);
 406                 }
 407
 408                 //
 409                 // Class initializer
 410                 //
 411                 static Tokenizer ()
 412                 {
 413                         Reset ();
 414                 }
 415
 416                 public static void Reset ()
 417                 {
 418                         InitTokens ();
 419                         csharp_format_info = NumberFormatInfo.InvariantInfo;
 420                         styles = NumberStyles.Float;
 421
 422                         string_builder = new System.Text.StringBuilder ();
 423                 }
 424
 425                 int GetKeyword (char[] id, int id_len)
 426                 {
 427                         /*
 428                          * Keywords are stored in an array of hashtables grouped by their
 429                          * length.
 430                          */
 431
 432                         if ((id_len >= keywords.Length) || (keywords [id_len] == null))
 433                                 return -1;
 434                         object o = keywords [id_len] [id];
 435
 436                         if (o == null)
 437                                 return -1;
 438
 439                         int res = (int) o;
 440
 441                         if (!handle_get_set && (res == Token.GET || res == Token.SET))
 442                                 return -1;
 443                         if (!handle_remove_add && (res == Token.REMOVE || res == Token.ADD))
 444                                 return -1;
 445                         if (!handle_assembly && res == Token.ASSEMBLY)
 446                                 return -1;
 447
 448                         //
 449                         // A query expression is any expression that starts with `from identifier'
 450                         // followed by any token except ; , =
 451                         //
 452                         if (query_parsing == 0) {
 453                                 if (res == Token.FROM && !lambda_arguments_parsing) {
 454                                         PushPosition ();
 455                                         // HACK: to disable generics micro-parser, because PushPosition does not
 456                                         // store identifiers array
 457                                         parsing_generic_less_than = 1;
 458                                         switch (xtoken ()) {
 459                                                 case Token.IDENTIFIER:
 460                                                 case Token.INT:
 461                                                 case Token.BOOL:
 462                                                 case Token.BYTE:
 463                                                 case Token.CHAR:
 464                                                 case Token.DECIMAL:
 465                                                 case Token.FLOAT:
 466                                                 case Token.LONG:
 467                                                 case Token.OBJECT:
 468                                                 case Token.STRING:
 469                                                 case Token.UINT:
 470                                                 case Token.ULONG:
 471                                                         int next_token = xtoken ();
 472                                                         if (next_token == Token.SEMICOLON || next_token == Token.COMMA || next_token == Token.EQUALS)
 473                                                                 goto default;
 474
 475                                                         ++query_parsing;
 476                                                         if (RootContext.Version <= LanguageVersion.ISO_2)
 477                                                                 Report.FeatureIsNotAvailable (Location, "query expressions");
 478                                                         break;
 479                                                 case Token.VOID:
 480                                                         Expression.Error_VoidInvalidInTheContext (Location);
 481                                                         break;
 482                                                 default:
 483                                                         PopPosition ();
 484                                                         // HACK: A token is not a keyword so we need to restore identifiers buffer
 485                                                         // which has been overwritten before we grabbed the identifier
 486                                                         id_builder [0] = 'f'; id_builder [1] = 'r'; id_builder [2] = 'o'; id_builder [3] = 'm';
 487                                                         return -1;
 488                                         }
 489                                         PopPosition ();
 490                                         return res;
 491                                 }
 492
 493                                 if (res > Token.QUERY_FIRST_TOKEN && res < Token.QUERY_LAST_TOKEN)
 494                                         return -1;
 495                         }
 496
 497                         if (res == Token.WHERE && !handle_where && query_parsing == 0)
 498                                 return -1;
 499
 500                         return res;
 501                 }
 502
 503                 public Location Location {
 504                         get { return current_location; }
 505                 }
 506
 507                 public Tokenizer (SeekableStreamReader input, CompilationUnit file)
 508                 {
 509                         this.ref_name = file;
 510                         this.file_name = file;
 511                         reader = input;
 512
 513                         putback_char = -1;
 514
 515                         xml_comment_buffer = new StringBuilder ();
 516
 517                         //
 518                         // FIXME: This could be `Location.Push' but we have to
 519                         // find out why the MS compiler allows this
 520                         //
 521                         Mono.CSharp.Location.Push (file, file);
 522                 }
 523
 524                 static bool is_identifier_start_character (char c)
 525                 {
 526                         return (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || c == '_' || Char.IsLetter (c);
 527                 }
 528
 529                 static bool is_identifier_part_character (char c)
 530                 {
 531                         return (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || c == '_' || (c >= '0' && c <= '9') ||
 532                                 Char.IsLetter (c) || Char.GetUnicodeCategory (c) == UnicodeCategory.ConnectorPunctuation;
 533                 }
 534
 535                 public static bool IsKeyword (string s)
 536                 {
 537                         return keyword_strings [s] != null;
 538                 }
 539
 540                 //
 541                 // Tests whether '(' is beggining of lambda parameters
 542                 //
 543                 bool IsLambdaOpenParens ()
 544                 {
 545                         int ntoken;
 546                         while ((ntoken = xtoken ()) != Token.EOF) {
 547                                 switch (ntoken) {
 548                                         case Token.CLOSE_PARENS:
 549                                                 return xtoken () == Token.ARROW;
 550
 551                                         case Token.STAR:
 552                                         case Token.SEMICOLON:
 553                                         case Token.OPEN_BRACE:
 554                                         case Token.OPEN_PARENS:
 555                                         case Token.LITERAL_STRING:
 556                                         case Token.LITERAL_INTEGER:
 557                                         case Token.LITERAL_FLOAT:
 558                                         case Token.LITERAL_DOUBLE:
 559                                         case Token.LITERAL_DECIMAL:
 560                                         case Token.LITERAL_CHARACTER:
 561                                         case Token.NULL:
 562                                         case Token.FALSE:
 563                                         case Token.TRUE:
 564                                         case Token.OP_INC:
 565                                         case Token.OP_DEC:
 566                                         case Token.OP_SHIFT_LEFT:
 567                                         case Token.OP_SHIFT_RIGHT:
 568                                         case Token.OP_LE:
 569                                         case Token.OP_GE:
 570                                         case Token.OP_EQ:
 571                                         case Token.OP_NE:
 572                                         case Token.OP_AND:
 573                                         case Token.OP_OR:
 574                                         case Token.BITWISE_AND:
 575                                         case Token.BITWISE_OR:
 576                                         case Token.PLUS:
 577                                         case Token.MINUS:
 578                                         case Token.DIV:
 579                                         case Token.NEW:
 580                                         case Token.THIS:
 581                                         case Token.BASE:
 582                                         case Token.TYPEOF:
 583                                                 return false;
 584                                 }
 585                         }
 586
 587                         Error_TokenExpected (",' or `)");
 588                         return false;
 589                 }
 590
 591                 public static bool IsValidIdentifier (string s)
 592                 {
 593                         if (s == null || s.Length == 0)
 594                                 return false;
 595
 596                         if (!is_identifier_start_character (s [0]))
 597                                 return false;
 598
 599                         for (int i = 1; i < s.Length; i ++)
 600                                 if (! is_identifier_part_character (s [i]))
 601                                         return false;
 602
 603                         return true;
 604                 }
 605
 606                 bool parse_less_than ()
 607                 {
 608                 start:
 609                         int the_token = token ();
 610                         if (the_token == Token.OPEN_BRACKET) {
 611                                 do {
 612                                         the_token = token ();
 613                                 } while (the_token != Token.CLOSE_BRACKET);
 614                                 the_token = token ();
 615                         }
 616                         switch (the_token) {
 617                         case Token.IDENTIFIER:
 618                         case Token.OBJECT:
 619                         case Token.STRING:
 620                         case Token.BOOL:
 621                         case Token.DECIMAL:
 622                         case Token.FLOAT:
 623                         case Token.DOUBLE:
 624                         case Token.SBYTE:
 625                         case Token.BYTE:
 626                         case Token.SHORT:
 627                         case Token.USHORT:
 628                         case Token.INT:
 629                         case Token.UINT:
 630                         case Token.LONG:
 631                         case Token.ULONG:
 632                         case Token.CHAR:
 633                         case Token.VOID:
 634                                 break;
 635
 636                         case Token.OP_GENERICS_GT:
 637                                 return true;
 638
 639                         default:
 640                                 return false;
 641                         }
 642                 again:
 643                         the_token = token ();
 644
 645                         if (the_token == Token.OP_GENERICS_GT)
 646                                 return true;
 647                         else if (the_token == Token.COMMA || the_token == Token.DOT || the_token == Token.DOUBLE_COLON)
 648                                 goto start;
 649                         else if (the_token == Token.INTERR || the_token == Token.STAR)
 650                                 goto again;
 651                         else if (the_token == Token.OP_GENERICS_LT) {
 652                                 if (!parse_less_than ())
 653                                         return false;
 654                                 goto again;
 655                         } else if (the_token == Token.OPEN_BRACKET) {
 656                         rank_specifiers:
 657                                 the_token = token ();
 658                                 if (the_token == Token.CLOSE_BRACKET)
 659                                         goto again;
 660                                 else if (the_token == Token.COMMA)
 661                                         goto rank_specifiers;
 662                                 return false;
 663                         }
 664
 665                         return false;
 666                 }
 667
 668                 public void PutbackNullable ()
 669                 {
 670                         if (nullable_pos < 0)
 671                                 throw new Exception ();
 672
 673                         current_token = -1;
 674                         val = null;
 675                         reader.Position = nullable_pos;
 676
 677                         putback_char = '?';
 678                 }
 679
 680                 public void PutbackCloseParens ()
 681                 {
 682                         putback_char = ')';
 683                 }
 684
 685
 686                 int nullable_pos = -1;
 687
 688                 public void CheckNullable (bool is_nullable)
 689                 {
 690                         if (is_nullable)
 691                                 nullable_pos = reader.Position;
 692                         else
 693                                 nullable_pos = -1;
 694                 }
 695
 696                 bool parse_generic_dimension (out int dimension)
 697                 {
 698                         dimension = 1;
 699
 700                 again:
 701                         int the_token = token ();
 702                         if (the_token == Token.OP_GENERICS_GT)
 703                                 return true;
 704                         else if (the_token == Token.COMMA) {
 705                                 dimension++;
 706                                 goto again;
 707                         }
 708
 709                         return false;
 710                 }
 711
 712                 public int peek_token ()
 713                 {
 714                         int the_token;
 715
 716                         PushPosition ();
 717                         the_token = token ();
 718                         PopPosition ();
 719
 720                         return the_token;
 721                 }
 722
 723                 int parsing_generic_less_than = 0;
 724
 725                 int is_punct (char c, ref bool doread)
 726                 {
 727                         int d;
 728                         int t;
 729
 730                         doread = false;
 731
 732                         switch (c){
 733                         case '{':
 734                                 val = Location;
 735                                 return Token.OPEN_BRACE;
 736                         case '}':
 737                                 val = Location;
 738                                 return Token.CLOSE_BRACE;
 739                         case '[':
 740                                 // To block doccomment inside attribute declaration.
 741                                 if (doc_state == XmlCommentState.Allowed)
 742                                         doc_state = XmlCommentState.NotAllowed;
 743                                 return Token.OPEN_BRACKET;
 744                         case ']':
 745                                 return Token.CLOSE_BRACKET;
 746                         case '(':
 747                                 if (!lambda_arguments_parsing) {
 748                                         lambda_arguments_parsing = true;
 749                                         PushPosition ();
 750                                         bool lambda_start = IsLambdaOpenParens ();
 751                                         PopPosition ();
 752                                         lambda_arguments_parsing = false;
 753                                         if (lambda_start) {
 754                                                 if (RootContext.Version <= LanguageVersion.ISO_2)
 755                                                         Report.FeatureIsNotAvailable (Location, "lambda expressions");
 756
 757                                                 return Token.OPEN_PARENS_LAMBDA;
 758                                         }
 759                                 }
 760                                 return Token.OPEN_PARENS;
 761                         case ')': {
 762                                 if (deambiguate_close_parens == 0)
 763                                         return Token.CLOSE_PARENS;
 764
 765                                 --deambiguate_close_parens;
 766
 767                                 PushPosition ();
 768
 769                                 int new_token = xtoken ();
 770
 771                                 PopPosition ();
 772
 773                                 if (new_token == Token.OPEN_PARENS)
 774                                         return Token.CLOSE_PARENS_OPEN_PARENS;
 775                                 else if (new_token == Token.MINUS)
 776                                         return Token.CLOSE_PARENS_MINUS;
 777                                 else if (IsCastToken (new_token))
 778                                         return Token.CLOSE_PARENS_CAST;
 779                                 else
 780                                         return Token.CLOSE_PARENS_NO_CAST;
 781                         }
 782
 783                         case ',':
 784                                 return Token.COMMA;
 785                         case ';':
 786                                 val = Location;
 787                                 return Token.SEMICOLON;
 788                         case '~':
 789                                 val = Location;
 790                                 return Token.TILDE;
 791                         case '?':
 792                                 d = peek_char ();
 793                                 if (d == '?') {
 794                                         get_char ();
 795                                         return Token.OP_COALESCING;
 796                                 }
 797                                 return Token.INTERR;
 798                         }
 799
 800                         if (c == '<') {
 801                                 if (parsing_generic_less_than++ > 0)
 802                                         return Token.OP_GENERICS_LT;
 803
 804                                 if (handle_typeof) {
 805                                         int dimension;
 806                                         PushPosition ();
 807                                         if (parse_generic_dimension (out dimension)) {
 808                                                 val = dimension;
 809                                                 DiscardPosition ();
 810                                                 return Token.GENERIC_DIMENSION;
 811                                         }
 812                                         PopPosition ();
 813                                 }
 814
 815                                 // Save current position and parse next token.
 816                                 PushPosition ();
 817                                 bool is_generic_lt = parse_less_than ();
 818                                 PopPosition ();
 819
 820                                 if (is_generic_lt) {
 821                                         return Token.OP_GENERICS_LT;
 822                                 } else
 823                                         parsing_generic_less_than = 0;
 824
 825                                 d = peek_char ();
 826                                 if (d == '<'){
 827                                         get_char ();
 828                                         d = peek_char ();
 829
 830                                         if (d == '='){
 831                                                 doread = true;
 832                                                 return Token.OP_SHIFT_LEFT_ASSIGN;
 833                                         }
 834                                         return Token.OP_SHIFT_LEFT;
 835                                 } else if (d == '='){
 836                                         doread = true;
 837                                         return Token.OP_LE;
 838                                 }
 839                                 return Token.OP_LT;
 840                         } else if (c == '>') {
 841                                 d = peek_char ();
 842
 843                                 if (d == '='){
 844                                         doread = true;
 845                                         return Token.OP_GE;
 846                                 }
 847
 848                                 if (parsing_generic_less_than > 1 || (parsing_generic_less_than == 1 && d != '>')) {
 849                                         parsing_generic_less_than--;
 850                                         return Token.OP_GENERICS_GT;
 851                                 }
 852
 853                                 if (d == '>') {
 854                                         get_char ();
 855                                         d = peek_char ();
 856
 857                                         if (d == '=') {
 858                                                 doread = true;
 859                                                 return Token.OP_SHIFT_RIGHT_ASSIGN;
 860                                         }
 861                                         return Token.OP_SHIFT_RIGHT;
 862                                 }
 863
 864                                 return Token.OP_GT;
 865                         }
 866
 867                         d = peek_char ();
 868                         if (c == '+'){
 869
 870                                 if (d == '+') {
 871                                         val = Location;
 872                                         t = Token.OP_INC;
 873                                 }
 874                                 else if (d == '=')
 875                                         t = Token.OP_ADD_ASSIGN;
 876                                 else {
 877                                         val = Location;
 878                                         return Token.PLUS;
 879                                 }
 880                                 doread = true;
 881                                 return t;
 882                         }
 883                         if (c == '-'){
 884                                 if (d == '-') {
 885                                         val = Location;
 886                                         t = Token.OP_DEC;
 887                                 }
 888                                 else if (d == '=')
 889                                         t = Token.OP_SUB_ASSIGN;
 890                                 else if (d == '>')
 891                                         t = Token.OP_PTR;
 892                                 else {
 893                                         val = Location;
 894                                         return Token.MINUS;
 895                                 }
 896                                 doread = true;
 897                                 return t;
 898                         }
 899
 900                         if (c == '!'){
 901                                 if (d == '='){
 902                                         doread = true;
 903                                         return Token.OP_NE;
 904                                 }
 905                                 val = Location;
 906                                 return Token.BANG;
 907                         }
 908
 909                         if (c == '='){
 910                                 if (d == '='){
 911                                         doread = true;
 912                                         return Token.OP_EQ;
 913                                 }
 914                                 if (d == '>'){
 915                                         doread = true;
 916                                         val = Location;
 917                                         return Token.ARROW;
 918                                 }
 919
 920                                 return Token.ASSIGN;
 921                         }
 922
 923                         if (c == '&'){
 924                                 if (d == '&'){
 925                                         doread = true;
 926                                         return Token.OP_AND;
 927                                 } else if (d == '='){
 928                                         doread = true;
 929                                         return Token.OP_AND_ASSIGN;
 930                                 }
 931                                 val = Location;
 932                                 return Token.BITWISE_AND;
 933                         }
 934
 935                         if (c == '|'){
 936                                 if (d == '|'){
 937                                         doread = true;
 938                                         return Token.OP_OR;
 939                                 } else if (d == '='){
 940                                         doread = true;
 941                                         return Token.OP_OR_ASSIGN;
 942                                 }
 943                                 return Token.BITWISE_OR;
 944                         }
 945
 946                         if (c == '*'){
 947                                 if (d == '='){
 948                                         doread = true;
 949                                         return Token.OP_MULT_ASSIGN;
 950                                 }
 951                                 val = Location;
 952                                 return Token.STAR;
 953                         }
 954
 955                         if (c == '/'){
 956                                 if (d == '='){
 957                                         doread = true;
 958                                         return Token.OP_DIV_ASSIGN;
 959                                 }
 960                                 return Token.DIV;
 961                         }
 962
 963                         if (c == '%'){
 964                                 if (d == '='){
 965                                         doread = true;
 966                                         return Token.OP_MOD_ASSIGN;
 967                                 }
 968                                 return Token.PERCENT;
 969                         }
 970
 971                         if (c == '^'){
 972                                 if (d == '='){
 973                                         doread = true;
 974                                         return Token.OP_XOR_ASSIGN;
 975                                 }
 976                                 return Token.CARRET;
 977                         }
 978
 979                         if (c == ':'){
 980                                 if (d == ':'){
 981                                         doread = true;
 982                                         return Token.DOUBLE_COLON;
 983                                 }
 984                                 val = Location;
 985                                 return Token.COLON;
 986                         }
 987
 988                         return Token.ERROR;
 989                 }
 990
 991                 int deambiguate_close_parens = 0;
 992
 993                 public void Deambiguate_CloseParens (object expression)
 994                 {
 995                         putback (')');
 996
 997                         // When any binary operation, a conditional is used we are sure it is not a cast
 998                         // maybe more.
 999
1000                         if (expression is Binary || expression is Conditional)
1001                                 return;
1002
1003                         deambiguate_close_parens++;
1004                 }
1005
1006                 bool decimal_digits (int c)
1007                 {
1008                         int d;
1009                         bool seen_digits = false;
1010
1011                         if (c != -1){
1012                                 if (number_pos == max_number_size)
1013                                         Error_NumericConstantTooLong ();
1014                                 number_builder [number_pos++] = (char) c;
1015                         }
1016
1017                         //
1018                         // We use peek_char2, because decimal_digits needs to do a
1019                         // 2-character look-ahead (5.ToString for example).
1020                         //
1021                         while ((d = peek_char2 ()) != -1){
1022                                 if (d >= '0' && d <= '9'){
1023                                         if (number_pos == max_number_size)
1024                                                 Error_NumericConstantTooLong ();
1025                                         number_builder [number_pos++] = (char) d;
1026                                         get_char ();
1027                                         seen_digits = true;
1028                                 } else
1029                                         break;
1030                         }
1031
1032                         return seen_digits;
1033                 }
1034
1035                 static bool is_hex (int e)
1036                 {
1037                         return (e >= '0' && e <= '9') || (e >= 'A' && e <= 'F') || (e >= 'a' && e <= 'f');
1038                 }
1039
1040                 static int real_type_suffix (int c)
1041                 {
1042                         int t;
1043
1044                         switch (c){
1045                         case 'F': case 'f':
1046                                 t =  Token.LITERAL_FLOAT;
1047                                 break;
1048                         case 'D': case 'd':
1049                                 t = Token.LITERAL_DOUBLE;
1050                                 break;
1051                         case 'M': case 'm':
1052                                  t= Token.LITERAL_DECIMAL;
1053                                 break;
1054                         default:
1055                                 return Token.NONE;
1056                         }
1057                         return t;
1058                 }
1059
1060                 int integer_type_suffix (ulong ul, int c)
1061                 {
1062                         bool is_unsigned = false;
1063                         bool is_long = false;
1064
1065                         if (c != -1){
1066                                 bool scanning = true;
1067                                 do {
1068                                         switch (c){
1069                                         case 'U': case 'u':
1070                                                 if (is_unsigned)
1071                                                         scanning = false;
1072                                                 is_unsigned = true;
1073                                                 get_char ();
1074                                                 break;
1075
1076                                         case 'l':
1077                                                 if (!is_unsigned){
1078                                                         //
1079                                                         // if we have not seen anything in between
1080                                                         // report this error
1081                                                         //
1082                                                         Report.Warning (78, 4, Location, "The 'l' suffix is easily confused with the digit '1' (use 'L' for clarity)");
1083                                                 }
1084                                                 //
1085                                                 // This goto statement causes the MS CLR 2.0 beta 1 csc to report an error, so
1086                                                 // work around that.
1087                                                 //
1088                                                 //goto case 'L';
1089                                                 if (is_long)
1090                                                         scanning = false;
1091                                                 is_long = true;
1092                                                 get_char ();
1093                                                 break;
1094
1095                                         case 'L':
1096                                                 if (is_long)
1097                                                         scanning = false;
1098                                                 is_long = true;
1099                                                 get_char ();
1100                                                 break;
1101
1102                                         default:
1103                                                 scanning = false;
1104                                                 break;
1105                                         }
1106                                         c = peek_char ();
1107                                 } while (scanning);
1108                         }
1109
1110                         if (is_long && is_unsigned){
1111                                 val = ul;
1112                                 return Token.LITERAL_INTEGER;
1113                         } else if (is_unsigned){
1114                                 // uint if possible, or ulong else.
1115
1116                                 if ((ul & 0xffffffff00000000) == 0)
1117                                         val = (uint) ul;
1118                                 else
1119                                         val = ul;
1120                         } else if (is_long){
1121                                 // long if possible, ulong otherwise
1122                                 if ((ul & 0x8000000000000000) != 0)
1123                                         val = ul;
1124                                 else
1125                                         val = (long) ul;
1126                         } else {
1127                                 // int, uint, long or ulong in that order
1128                                 if ((ul & 0xffffffff00000000) == 0){
1129                                         uint ui = (uint) ul;
1130
1131                                         if ((ui & 0x80000000) != 0)
1132                                                 val = ui;
1133                                         else
1134                                                 val = (int) ui;
1135                                 } else {
1136                                         if ((ul & 0x8000000000000000) != 0)
1137                                                 val = ul;
1138                                         else
1139                                                 val = (long) ul;
1140                                 }
1141                         }
1142                         return Token.LITERAL_INTEGER;
1143                 }
1144
1145                 //
1146                 // given `c' as the next char in the input decide whether
1147                 // we need to convert to a special type, and then choose
1148                 // the best representation for the integer
1149                 //
1150                 int adjust_int (int c)
1151                 {
1152                         try {
1153                                 if (number_pos > 9){
1154                                         ulong ul = (uint) (number_builder [0] - '0');
1155
1156                                         for (int i = 1; i < number_pos; i++){
1157                                                 ul = checked ((ul * 10) + ((uint)(number_builder [i] - '0')));
1158                                         }
1159                                         return integer_type_suffix (ul, c);
1160                                 } else {
1161                                         uint ui = (uint) (number_builder [0] - '0');
1162
1163                                         for (int i = 1; i < number_pos; i++){
1164                                                 ui = checked ((ui * 10) + ((uint)(number_builder [i] - '0')));
1165                                         }
1166                                         return integer_type_suffix (ui, c);
1167                                 }
1168                         } catch (OverflowException) {
1169                                 error_details = "Integral constant is too large";
1170                                 Report.Error (1021, Location, error_details);
1171                                 val = 0ul;
1172                                 return Token.LITERAL_INTEGER;
1173                         }
1174                         catch (FormatException) {
1175                                 Report.Error (1013, Location, "Invalid number");
1176                                 val = 0ul;
1177                                 return Token.LITERAL_INTEGER;
1178                         }
1179                 }
1180
1181                 int adjust_real (int t)
1182                 {
1183                         string s = new String (number_builder, 0, number_pos);
1184                         const string error_details = "Floating-point constant is outside the range of type `{0}'";
1185
1186                         switch (t){
1187                         case Token.LITERAL_DECIMAL:
1188                                 try {
1189                                         val = System.Decimal.Parse (s, styles, csharp_format_info);
1190                                 } catch (OverflowException) {
1191                                         val = 0m;
1192                                         Report.Error (594, Location, error_details, "decimal");
1193                                 }
1194                                 break;
1195                         case Token.LITERAL_FLOAT:
1196                                 try {
1197                                         val = float.Parse (s, styles, csharp_format_info);
1198                                 } catch (OverflowException) {
1199                                         val = 0.0f;
1200                                         Report.Error (594, Location, error_details, "float");
1201                                 }
1202                                 break;
1203
1204                         case Token.LITERAL_DOUBLE:
1205                         case Token.NONE:
1206                                 t = Token.LITERAL_DOUBLE;
1207                                 try {
1208                                         val = System.Double.Parse (s, styles, csharp_format_info);
1209                                 } catch (OverflowException) {
1210                                         val = 0.0;
1211                                         Report.Error (594, Location, error_details, "double");
1212                                 }
1213                                 break;
1214                         }
1215                         return t;
1216                 }
1217
1218                 int handle_hex ()
1219                 {
1220                         int d;
1221                         ulong ul;
1222
1223                         get_char ();
1224                         while ((d = peek_char ()) != -1){
1225                                 if (is_hex (d)){
1226                                         number_builder [number_pos++] = (char) d;
1227                                         get_char ();
1228                                 } else
1229                                         break;
1230                         }
1231
1232                         string s = new String (number_builder, 0, number_pos);
1233                         try {
1234                                 if (number_pos <= 8)
1235                                         ul = System.UInt32.Parse (s, NumberStyles.HexNumber);
1236                                 else
1237                                         ul = System.UInt64.Parse (s, NumberStyles.HexNumber);
1238                         } catch (OverflowException){
1239                                 error_details = "Integral constant is too large";
1240                                 Report.Error (1021, Location, error_details);
1241                                 val = 0ul;
1242                                 return Token.LITERAL_INTEGER;
1243                         }
1244                         catch (FormatException) {
1245                                 Report.Error (1013, Location, "Invalid number");
1246                                 val = 0ul;
1247                                 return Token.LITERAL_INTEGER;
1248                         }
1249
1250                         return integer_type_suffix (ul, peek_char ());
1251                 }
1252
1253                 //
1254                 // Invoked if we know we have .digits or digits
1255                 //
1256                 int is_number (int c)
1257                 {
1258                         bool is_real = false;
1259                         int type;
1260
1261                         number_pos = 0;
1262
1263                         if (c >= '0' && c <= '9'){
1264                                 if (c == '0'){
1265                                         int peek = peek_char ();
1266
1267                                         if (peek == 'x' || peek == 'X')
1268                                                 return handle_hex ();
1269                                 }
1270                                 decimal_digits (c);
1271                                 c = get_char ();
1272                         }
1273
1274                         //
1275                         // We need to handle the case of
1276                         // "1.1" vs "1.string" (LITERAL_FLOAT vs NUMBER DOT IDENTIFIER)
1277                         //
1278                         if (c == '.'){
1279                                 if (decimal_digits ('.')){
1280                                         is_real = true;
1281                                         c = get_char ();
1282                                 } else {
1283                                         putback ('.');
1284                                         number_pos--;
1285                                         return adjust_int (-1);
1286                                 }
1287                         }
1288
1289                         if (c == 'e' || c == 'E'){
1290                                 is_real = true;
1291                                 if (number_pos == max_number_size)
1292                                         Error_NumericConstantTooLong ();
1293                                 number_builder [number_pos++] = 'e';
1294                                 c = get_char ();
1295
1296                                 if (c == '+'){
1297                                         if (number_pos == max_number_size)
1298                                                 Error_NumericConstantTooLong ();
1299                                         number_builder [number_pos++] = '+';
1300                                         c = -1;
1301                                 } else if (c == '-') {
1302                                         if (number_pos == max_number_size)
1303                                                 Error_NumericConstantTooLong ();
1304                                         number_builder [number_pos++] = '-';
1305                                         c = -1;
1306                                 } else {
1307                                         if (number_pos == max_number_size)
1308                                                 Error_NumericConstantTooLong ();
1309                                         number_builder [number_pos++] = '+';
1310                                 }
1311
1312                                 decimal_digits (c);
1313                                 c = get_char ();
1314                         }
1315
1316                         type = real_type_suffix (c);
1317                         if (type == Token.NONE && !is_real){
1318                                 putback (c);
1319                                 return adjust_int (c);
1320                         } else
1321                                 is_real = true;
1322
1323                         if (type == Token.NONE){
1324                                 putback (c);
1325                         }
1326
1327                         if (is_real)
1328                                 return adjust_real (type);
1329
1330                         Console.WriteLine ("This should not be reached");
1331                         throw new Exception ("Is Number should never reach this point");
1332                 }
1333
1334                 //
1335                 // Accepts exactly count (4 or 8) hex, no more no less
1336                 //
1337                 int getHex (int count, out bool error)
1338                 {
1339                         int i;
1340                         int total = 0;
1341                         int c;
1342                         int top = count != -1 ? count : 4;
1343
1344                         get_char ();
1345                         error = false;
1346                         for (i = 0; i < top; i++){
1347                                 c = get_char ();
1348
1349                                 if (c >= '0' && c <= '9')
1350                                         c = (int) c - (int) '0';
1351                                 else if (c >= 'A' && c <= 'F')
1352                                         c = (int) c - (int) 'A' + 10;
1353                                 else if (c >= 'a' && c <= 'f')
1354                                         c = (int) c - (int) 'a' + 10;
1355                                 else {
1356                                         error = true;
1357                                         return 0;
1358                                 }
1359
1360                                 total = (total * 16) + c;
1361                                 if (count == -1){
1362                                         int p = peek_char ();
1363                                         if (p == -1)
1364                                                 break;
1365                                         if (!is_hex ((char)p))
1366                                                 break;
1367                                 }
1368                         }
1369                         return total;
1370                 }
1371
1372                 int escape (int c)
1373                 {
1374                         bool error;
1375                         int d;
1376                         int v;
1377
1378                         d = peek_char ();
1379                         if (c != '\\')
1380                                 return c;
1381
1382                         switch (d){
1383                         case 'a':
1384                                 v = '\a'; break;
1385                         case 'b':
1386                                 v = '\b'; break;
1387                         case 'n':
1388                                 v = '\n'; break;
1389                         case 't':
1390                                 v = '\t'; break;
1391                         case 'v':
1392                                 v = '\v'; break;
1393                         case 'r':
1394                                 v = '\r'; break;
1395                         case '\\':
1396                                 v = '\\'; break;
1397                         case 'f':
1398                                 v = '\f'; break;
1399                         case '0':
1400                                 v = 0; break;
1401                         case '"':
1402                                 v = '"'; break;
1403                         case '\'':
1404                                 v = '\''; break;
1405                         case 'x':
1406                                 v = getHex (-1, out error);
1407                                 if (error)
1408                                         goto default;
1409                                 return v;
1410                         case 'u':
1411                         case 'U':
1412                                 return EscapeUnicode (d);
1413                         default:
1414                                 Report.Error (1009, Location, "Unrecognized escape sequence `\\{0}'", ((char)d).ToString ());
1415                                 return d;
1416                         }
1417                         get_char ();
1418                         return v;
1419                 }
1420
1421                 int EscapeUnicode (int ch)
1422                 {
1423                         bool error;
1424                         if (ch == 'U') {
1425                                 ch = getHex (8, out error);
1426                         } else {
1427                                 ch = getHex (4, out error);
1428                         }
1429
1430                         if (error)
1431                                 Report.Error (1009, Location, "Unrecognized escape sequence");
1432
1433                         return ch;
1434                 }
1435
1436                 int get_char ()
1437                 {
1438                         int x;
1439                         if (putback_char != -1) {
1440                                 x = putback_char;
1441                                 putback_char = -1;
1442                         } else
1443                                 x = reader.Read ();
1444                         if (x == '\n') {
1445                                 advance_line ();
1446                         } else {
1447                                 col++;
1448                         }
1449                         return x;
1450                 }
1451
1452                 void advance_line ()
1453                 {
1454                         line++;
1455                         ref_line++;
1456                         previous_col = col;
1457                         col = 0;
1458                 }
1459
1460                 int peek_char ()
1461                 {
1462                         if (putback_char != -1)
1463                                 return putback_char;
1464                         putback_char = reader.Read ();
1465                         return putback_char;
1466                 }
1467
1468                 int peek_char2 ()
1469                 {
1470                         if (putback_char != -1)
1471                                 return putback_char;
1472                         return reader.Peek ();
1473                 }
1474
1475                 void putback (int c)
1476                 {
1477                         if (putback_char != -1){
1478                                 Console.WriteLine ("Col: " + col);
1479                                 Console.WriteLine ("Row: " + line);
1480                                 Console.WriteLine ("Name: " + ref_name.Name);
1481                                 Console.WriteLine ("Current [{0}] putting back [{1}]  ", putback_char, c);
1482                                 throw new Exception ("This should not happen putback on putback");
1483                         }
1484                         if (c == '\n' || col == 0) {
1485                                 // It won't happen though.
1486                                 line--;
1487                                 ref_line--;
1488                                 col = previous_col;
1489                         }
1490                         else
1491                                 col--;
1492                         putback_char = c;
1493                 }
1494
1495                 public bool advance ()
1496                 {
1497                         return peek_char () != -1;
1498                 }
1499
1500                 public Object Value {
1501                         get {
1502                                 return val;
1503                         }
1504                 }
1505
1506                 public Object value ()
1507                 {
1508                         return val;
1509                 }
1510
1511                 static bool IsCastToken (int token)
1512                 {
1513                         switch (token) {
1514                         case Token.BANG:
1515                         case Token.TILDE:
1516                         case Token.IDENTIFIER:
1517                         case Token.LITERAL_INTEGER:
1518                         case Token.LITERAL_FLOAT:
1519                         case Token.LITERAL_DOUBLE:
1520                         case Token.LITERAL_DECIMAL:
1521                         case Token.LITERAL_CHARACTER:
1522                         case Token.LITERAL_STRING:
1523                         case Token.BASE:
1524                         case Token.CHECKED:
1525                         case Token.DELEGATE:
1526                         case Token.FALSE:
1527                         case Token.FIXED:
1528                         case Token.NEW:
1529                         case Token.NULL:
1530                         case Token.SIZEOF:
1531                         case Token.THIS:
1532                         case Token.THROW:
1533                         case Token.TRUE:
1534                         case Token.TYPEOF:
1535                         case Token.UNCHECKED:
1536                         case Token.UNSAFE:
1537                         case Token.DEFAULT:
1538
1539                                 //
1540                                 // These can be part of a member access
1541                                 //
1542                         case Token.INT:
1543                         case Token.UINT:
1544                         case Token.SHORT:
1545                         case Token.USHORT:
1546                         case Token.LONG:
1547                         case Token.ULONG:
1548                         case Token.DOUBLE:
1549                         case Token.FLOAT:
1550                         case Token.CHAR:
1551                         case Token.BYTE:
1552                         case Token.DECIMAL:
1553                                 return true;
1554
1555                         default:
1556                                 return false;
1557                         }
1558                 }
1559
1560                 public int token ()
1561                 {
1562                         current_token = xtoken ();
1563
1564                         if (current_token != Token.DEFAULT)
1565                                 return current_token;
1566
1567                         PushPosition();
1568                         int c = xtoken();
1569                         if (c == -1)
1570                                 current_token = Token.ERROR;
1571                         else if (c == Token.OPEN_PARENS)
1572                                 current_token = Token.DEFAULT_OPEN_PARENS;
1573                         else if (c == Token.COLON)
1574                                 current_token = Token.DEFAULT_COLON;
1575                         else
1576                                 PopPosition();
1577
1578                         return current_token;
1579                 }
1580
1581                 static StringBuilder static_cmd_arg = new System.Text.StringBuilder ();
1582
1583                 void get_cmd_arg (out string cmd, out string arg)
1584                 {
1585                         int c;
1586
1587                         tokens_seen = false;
1588                         arg = "";
1589                         static_cmd_arg.Length = 0;
1590
1591                         // skip over white space
1592                         while ((c = get_char ()) != -1 && (c != '\n') && ((c == '\r') || (c == ' ') || (c == '\t')))
1593                                 ;
1594
1595                         while ((c != -1) && (c != '\n') && (c != ' ') && (c != '\t') && (c != '\r')){
1596                                 if (is_identifier_part_character ((char)c)){
1597                                         static_cmd_arg.Append ((char)c);
1598                                         c = get_char ();
1599                                         continue;
1600                                 }
1601
1602                                 if (c == '\\') {
1603                                         int peek = peek_char ();
1604                                         if (peek == 'U' || peek == 'u') {
1605                                                 c = EscapeUnicode (c);
1606                                                 continue;
1607                                         }
1608                                 }
1609
1610                                 cmd = null;
1611                                 return;
1612                         }
1613
1614                         cmd = static_cmd_arg.ToString ();
1615
1616                         if (c == '\n' || c == '\r'){
1617                                 return;
1618                         }
1619
1620                         // skip over white space
1621                         while ((c = get_char ()) != -1 && (c != '\n') && ((c == '\r') || (c == ' ') || (c == '\t')))
1622                                 ;
1623
1624                         if (c == '\n'){
1625                                 return;
1626                         } else if (c == '\r'){
1627                                 return;
1628                         } else if (c == -1){
1629                                 arg = "";
1630                                 return;
1631                         }
1632
1633                         static_cmd_arg.Length = 0;
1634                         do {
1635                                 if (c == '\\') {
1636                                         int peek = peek_char ();
1637                                         if (peek == 'U' || peek == 'u') {
1638                                                 c = EscapeUnicode (c);
1639                                                 continue;
1640                                         }
1641                                 }
1642                                 static_cmd_arg.Append ((char) c);
1643                         } while ((c = get_char ()) != -1 && (c != '\n') && (c != '\r'));
1644
1645                         arg = static_cmd_arg.ToString ();
1646                 }
1647
1648                 //
1649                 // Handles the #line directive
1650                 //
1651                 bool PreProcessLine (string arg)
1652                 {
1653                         if (arg.Length == 0)
1654                                 return false;
1655
1656                         if (arg == "default"){
1657                                 ref_line = line;
1658                                 ref_name = file_name;
1659                                 hidden = false;
1660                                 Location.Push (file_name, ref_name);
1661                                 return true;
1662                         } else if (arg == "hidden"){
1663                                 hidden = true;
1664                                 return true;
1665                         }
1666
1667                         try {
1668                                 int pos;
1669
1670                                 if ((pos = arg.IndexOf (' ')) != -1 && pos != 0){
1671                                         ref_line = System.Int32.Parse (arg.Substring (0, pos));
1672                                         pos++;
1673
1674                                         char [] quotes = { '\"' };
1675
1676                                         string name = arg.Substring (pos). Trim (quotes);
1677                                         ref_name = Location.LookupFile (file_name, name);
1678                                         file_name.AddFile (ref_name);
1679                                         hidden = false;
1680                                         Location.Push (file_name, ref_name);
1681                                 } else {
1682                                         ref_line = System.Int32.Parse (arg);
1683                                         hidden = false;
1684                                 }
1685                         } catch {
1686                                 return false;
1687                         }
1688
1689                         return true;
1690                 }
1691
1692                 //
1693                 // Handles #define and #undef
1694                 //
1695                 void PreProcessDefinition (bool is_define, string ident, bool caller_is_taking)
1696                 {
1697                         if (ident.Length == 0 || ident == "true" || ident == "false"){
1698                                 Report.Error (1001, Location, "Missing identifer to pre-processor directive");
1699                                 return;
1700                         }
1701
1702                         if (ident.IndexOfAny (simple_whitespaces) != -1){
1703                                 Error_EndLineExpected ();
1704                                 return;
1705                         }
1706
1707                         if (!is_identifier_start_character (ident [0]))
1708                                 Report.Error (1001, Location, "Identifier expected: " + ident);
1709
1710                         foreach (char c in ident.Substring (1)){
1711                                 if (!is_identifier_part_character (c)){
1712                                         Report.Error (1001, Location, "Identifier expected: " + ident);
1713                                         return;
1714                                 }
1715                         }
1716
1717                         if (!caller_is_taking)
1718                                 return;
1719
1720                         if (is_define) {
1721                                 //
1722                                 // #define ident
1723                                 //
1724                                 if (RootContext.IsConditionalDefined (ident))
1725                                         return;
1726
1727                                 file_name.AddDefine (ident);
1728                         } else {
1729                                 //
1730                                 // #undef ident
1731                                 //
1732                                 file_name.AddUndefine (ident);
1733                         }
1734                 }
1735
1736                 static byte read_hex (string arg, int pos, out bool error)
1737                 {
1738                         error = false;
1739
1740                         int total;
1741                         char c = arg [pos];
1742
1743                         if ((c >= '0') && (c <= '9'))
1744                                 total = (int) c - (int) '0';
1745                         else if ((c >= 'A') && (c <= 'F'))
1746                                 total = (int) c - (int) 'A' + 10;
1747                         else if ((c >= 'a') && (c <= 'f'))
1748                                 total = (int) c - (int) 'a' + 10;
1749                         else {
1750                                 error = true;
1751                                 return 0;
1752                         }
1753
1754                         total *= 16;
1755                         c = arg [pos+1];
1756
1757                         if ((c >= '0') && (c <= '9'))
1758                                 total += (int) c - (int) '0';
1759                         else if ((c >= 'A') && (c <= 'F'))
1760                                 total += (int) c - (int) 'A' + 10;
1761                         else if ((c >= 'a') && (c <= 'f'))
1762                                 total += (int) c - (int) 'a' + 10;
1763                         else {
1764                                 error = true;
1765                                 return 0;
1766                         }
1767
1768                         return (byte) total;
1769                 }
1770
1771                 /// <summary>
1772                 /// Handles #pragma checksum
1773                 /// </summary>
1774                 bool PreProcessPragmaChecksum (string arg)
1775                 {
1776                         if ((arg [0] != ' ') && (arg [0] != '\t'))
1777                                 return false;
1778
1779                         arg = arg.Trim (simple_whitespaces);
1780                         if ((arg.Length < 2) || (arg [0] != '"'))
1781                                 return false;
1782
1783                         StringBuilder file_sb = new StringBuilder ();
1784
1785                         int pos = 1;
1786                         char ch;
1787                         while ((ch = arg [pos++]) != '"') {
1788                                 if (pos >= arg.Length)
1789                                         return false;
1790
1791                                 if (ch == '\\') {
1792                                         if (pos+1 >= arg.Length)
1793                                                 return false;
1794                                         ch = arg [pos++];
1795                                 }
1796
1797                                 file_sb.Append (ch);
1798                         }
1799
1800                         if ((pos+2 >= arg.Length) || ((arg [pos] != ' ') && (arg [pos] != '\t')))
1801                                 return false;
1802
1803                         arg = arg.Substring (pos).Trim (simple_whitespaces);
1804                         if ((arg.Length < 42) || (arg [0] != '"') || (arg [1] != '{') ||
1805                             (arg [10] != '-') || (arg [15] != '-') || (arg [20] != '-') ||
1806                             (arg [25] != '-') || (arg [38] != '}') || (arg [39] != '"'))
1807                                 return false;
1808
1809                         bool error;
1810                         byte[] guid_bytes = new byte [16];
1811
1812                         for (int i = 0; i < 4; i++) {
1813                                 guid_bytes [i] = read_hex (arg, 2+2*i, out error);
1814                                 if (error)
1815                                         return false;
1816                         }
1817                         for (int i = 0; i < 2; i++) {
1818                                 guid_bytes [i+4] = read_hex (arg, 11+2*i, out error);
1819                                 if (error)
1820                                         return false;
1821                                 guid_bytes [i+6] = read_hex (arg, 16+2*i, out error);
1822                                 if (error)
1823                                         return false;
1824                                 guid_bytes [i+8] = read_hex (arg, 21+2*i, out error);
1825                                 if (error)
1826                                         return false;
1827                         }
1828
1829                         for (int i = 0; i < 6; i++) {
1830                                 guid_bytes [i+10] = read_hex (arg, 26+2*i, out error);
1831                                 if (error)
1832                                         return false;
1833                         }
1834
1835                         arg = arg.Substring (40).Trim (simple_whitespaces);
1836                         if ((arg.Length < 34) || (arg [0] != '"') || (arg [33] != '"'))
1837                                 return false;
1838
1839                         byte[] checksum_bytes = new byte [16];
1840                         for (int i = 0; i < 16; i++) {
1841                                 checksum_bytes [i] = read_hex (arg, 1+2*i, out error);
1842                                 if (error)
1843                                         return false;
1844                         }
1845
1846                         arg = arg.Substring (34).Trim (simple_whitespaces);
1847                         if (arg.Length > 0)
1848                                 return false;
1849
1850                         SourceFile file = Location.LookupFile (file_name, file_sb.ToString ());
1851                         file.SetChecksum (guid_bytes, checksum_bytes);
1852                         ref_name.AutoGenerated = true;
1853                         return true;
1854                 }
1855
1856                 /// <summary>
1857                 /// Handles #pragma directive
1858                 /// </summary>
1859                 void PreProcessPragma (string arg)
1860                 {
1861                         const string warning = "warning";
1862                         const string w_disable = "warning disable";
1863                         const string w_restore = "warning restore";
1864                         const string checksum = "checksum";
1865
1866                         if (arg == w_disable) {
1867                                 Report.RegisterWarningRegion (Location).WarningDisable (Location.Row);
1868                                 return;
1869                         }
1870
1871                         if (arg == w_restore) {
1872                                 Report.RegisterWarningRegion (Location).WarningEnable (Location.Row);
1873                                 return;
1874                         }
1875
1876                         if (arg.StartsWith (w_disable)) {
1877                                 int[] codes = ParseNumbers (arg.Substring (w_disable.Length));
1878                                 foreach (int code in codes) {
1879                                         if (code != 0)
1880                                                 Report.RegisterWarningRegion (Location).WarningDisable (Location, code);
1881                                 }
1882                                 return;
1883                         }
1884
1885                         if (arg.StartsWith (w_restore)) {
1886                                 int[] codes = ParseNumbers (arg.Substring (w_restore.Length));
1887                                 Hashtable w_table = Report.warning_ignore_table;
1888                                 foreach (int code in codes) {
1889                                         if (w_table != null && w_table.Contains (code))
1890                                                 Report.Warning (1635, 1, Location, String.Format ("Cannot restore warning `CS{0:0000}' because it was disabled globally", code));
1891                                         Report.RegisterWarningRegion (Location).WarningEnable (Location, code);
1892                                 }
1893                                 return;
1894                         }
1895
1896                         if (arg.StartsWith (warning)) {
1897                                 Report.Warning (1634, 1, Location, "Expected disable or restore");
1898                                 return;
1899                         }
1900
1901                         if (arg.StartsWith (checksum)) {
1902                                 if (!PreProcessPragmaChecksum (arg.Substring (checksum.Length)))
1903                                         Warning_InvalidPragmaChecksum ();
1904                                 return;
1905                         }
1906
1907                         Report.Warning (1633, 1, Location, "Unrecognized #pragma directive");
1908                 }
1909
1910                 int[] ParseNumbers (string text)
1911                 {
1912                         string[] string_array = text.Split (',');
1913                         int[] values = new int [string_array.Length];
1914                         int index = 0;
1915                         foreach (string string_code in string_array) {
1916                                 try {
1917                                         values[index++] = int.Parse (string_code, System.Globalization.CultureInfo.InvariantCulture);
1918                                 }
1919                                 catch (FormatException) {
1920                                         Report.Warning (1692, 1, Location, "Invalid number");
1921                                 }
1922                         }
1923                         return values;
1924                 }
1925
1926                 bool eval_val (string s)
1927                 {
1928                         if (s == "true")
1929                                 return true;
1930                         if (s == "false")
1931                                 return false;
1932
1933                         return file_name.IsConditionalDefined (s);
1934                 }
1935
1936                 bool pp_primary (ref string s)
1937                 {
1938                         s = s.Trim ();
1939                         int len = s.Length;
1940
1941                         if (len > 0){
1942                                 char c = s [0];
1943
1944                                 if (c == '('){
1945                                         s = s.Substring (1);
1946                                         bool val = pp_expr (ref s, false);
1947                                         if (s.Length > 0 && s [0] == ')'){
1948                                                 s = s.Substring (1);
1949                                                 return val;
1950                                         }
1951                                         Error_InvalidDirective ();
1952                                         return false;
1953                                 }
1954
1955                                 if (is_identifier_start_character (c)){
1956                                         int j = 1;
1957
1958                                         while (j < len){
1959                                                 c = s [j];
1960
1961                                                 if (is_identifier_part_character (c)){
1962                                                         j++;
1963                                                         continue;
1964                                                 }
1965                                                 bool v = eval_val (s.Substring (0, j));
1966                                                 s = s.Substring (j);
1967                                                 return v;
1968                                         }
1969                                         bool vv = eval_val (s);
1970                                         s = "";
1971                                         return vv;
1972                                 }
1973                         }
1974                         Error_InvalidDirective ();
1975                         return false;
1976                 }
1977
1978                 bool pp_unary (ref string s)
1979                 {
1980                         s = s.Trim ();
1981                         int len = s.Length;
1982
1983                         if (len > 0){
1984                                 if (s [0] == '!'){
1985                                         if (len > 1 && s [1] == '='){
1986                                                 Error_InvalidDirective ();
1987                                                 return false;
1988                                         }
1989                                         s = s.Substring (1);
1990                                         return ! pp_primary (ref s);
1991                                 } else
1992                                         return pp_primary (ref s);
1993                         } else {
1994                                 Error_InvalidDirective ();
1995                                 return false;
1996                         }
1997                 }
1998
1999                 bool pp_eq (ref string s)
2000                 {
2001                         bool va = pp_unary (ref s);
2002
2003                         s = s.Trim ();
2004                         int len = s.Length;
2005                         if (len > 0){
2006                                 if (s [0] == '='){
2007                                         if (len > 2 && s [1] == '='){
2008                                                 s = s.Substring (2);
2009                                                 return va == pp_unary (ref s);
2010                                         } else {
2011                                                 Error_InvalidDirective ();
2012                                                 return false;
2013                                         }
2014                                 } else if (s [0] == '!' && len > 1 && s [1] == '='){
2015                                         s = s.Substring (2);
2016
2017                                         return va != pp_unary (ref s);
2018
2019                                 }
2020                         }
2021
2022                         return va;
2023
2024                 }
2025
2026                 bool pp_and (ref string s)
2027                 {
2028                         bool va = pp_eq (ref s);
2029
2030                         s = s.Trim ();
2031                         int len = s.Length;
2032                         if (len > 0){
2033                                 if (s [0] == '&'){
2034                                         if (len > 2 && s [1] == '&'){
2035                                                 s = s.Substring (2);
2036                                                 return (va & pp_and (ref s));
2037                                         } else {
2038                                                 Error_InvalidDirective ();
2039                                                 return false;
2040                                         }
2041                                 }
2042                         }
2043                         return va;
2044                 }
2045
2046                 //
2047                 // Evaluates an expression for `#if' or `#elif'
2048                 //
2049                 bool pp_expr (ref string s, bool isTerm)
2050                 {
2051                         bool va = pp_and (ref s);
2052                         s = s.Trim ();
2053                         int len = s.Length;
2054                         if (len > 0){
2055                                 char c = s [0];
2056
2057                                 if (c == '|'){
2058                                         if (len > 2 && s [1] == '|'){
2059                                                 s = s.Substring (2);
2060                                                 return va | pp_expr (ref s, isTerm);
2061                                         } else {
2062                                                 Error_InvalidDirective ();
2063                                                 return false;
2064                                         }
2065                                 }
2066                                 if (isTerm) {
2067                                         Error_EndLineExpected ();
2068                                         return false;
2069                                 }
2070                         }
2071
2072                         return va;
2073                 }
2074
2075                 bool eval (string s)
2076                 {
2077                         bool v = pp_expr (ref s, true);
2078                         s = s.Trim ();
2079                         if (s.Length != 0){
2080                                 return false;
2081                         }
2082
2083                         return v;
2084                 }
2085
2086                 void Error_NumericConstantTooLong ()
2087                 {
2088                         Report.Error (1021, Location, "Numeric constant too long");
2089                 }
2090
2091                 void Error_InvalidDirective ()
2092                 {
2093                         Report.Error (1517, Location, "Invalid preprocessor directive");
2094                 }
2095
2096                 void Error_UnexpectedDirective (string extra)
2097                 {
2098                         Report.Error (
2099                                 1028, Location,
2100                                 "Unexpected processor directive (" + extra + ")");
2101                 }
2102
2103                 void Error_TokenExpected (string token)
2104                 {
2105                         Report.Error (1026, Location, "Expected `{0}'", token);
2106                 }
2107
2108                 void Error_TokensSeen ()
2109                 {
2110                         Report.Error (1032, Location,
2111                                 "Cannot define or undefine preprocessor symbols after first token in file");
2112                 }
2113
2114                 void Eror_WrongPreprocessorLocation ()
2115                 {
2116                         Report.Error (1040, Location,
2117                                 "Preprocessor directives must appear as the first non-whitespace character on a line");
2118                 }
2119
2120                 void Error_EndLineExpected ()
2121                 {
2122                         Report.Error (1025, Location, "Single-line comment or end-of-line expected");
2123                 }
2124
2125                 void Warning_InvalidPragmaChecksum ()
2126                 {
2127                         Report.Warning (1695, 1, Location,
2128                                         "Invalid #pragma checksum syntax; should be " +
2129                                         "#pragma checksum \"filename\" " +
2130                                         "\"{XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX}\" \"XXXX...\"");
2131                 }
2132                 //
2133                 // if true, then the code continues processing the code
2134                 // if false, the code stays in a loop until another directive is
2135                 // reached.
2136                 // When caller_is_taking is false we ignore all directives except the ones
2137                 // which can help us to identify where the #if block ends
2138                 bool handle_preprocessing_directive (bool caller_is_taking)
2139                 {
2140                         string cmd, arg;
2141                         bool region_directive = false;
2142
2143                         get_cmd_arg (out cmd, out arg);
2144
2145                         // Eat any trailing whitespaces and single-line comments
2146                         if (arg.IndexOf ("//") != -1)
2147                                 arg = arg.Substring (0, arg.IndexOf ("//"));
2148                         arg = arg.Trim (simple_whitespaces);
2149
2150                         //
2151                         // The first group of pre-processing instructions is always processed
2152                         //
2153                         switch (cmd){
2154                         case "region":
2155                                 region_directive = true;
2156                                 arg = "true";
2157                                 goto case "if";
2158
2159                         case "endregion":
2160                                 if (ifstack == null || ifstack.Count == 0){
2161                                         Error_UnexpectedDirective ("no #region for this #endregion");
2162                                         return true;
2163                                 }
2164                                 int pop = (int) ifstack.Pop ();
2165
2166                                 if ((pop & REGION) == 0)
2167                                         Report.Error (1027, Location, "Expected `#endif' directive");
2168
2169                                 return caller_is_taking;
2170
2171                         case "if":
2172                                 if (ifstack == null)
2173                                         ifstack = new Stack (2);
2174
2175                                 int flags = region_directive ? REGION : 0;
2176                                 if (ifstack.Count == 0){
2177                                         flags |= PARENT_TAKING;
2178                                 } else {
2179                                         int state = (int) ifstack.Peek ();
2180                                         if ((state & TAKING) != 0) {
2181                                                 flags |= PARENT_TAKING;
2182                                         }
2183                                 }
2184
2185                                 if (caller_is_taking && eval (arg)) {
2186                                         ifstack.Push (flags | TAKING);
2187                                         return true;
2188                                 }
2189                                 ifstack.Push (flags);
2190                                 return false;
2191
2192                         case "endif":
2193                                 if (ifstack == null || ifstack.Count == 0){
2194                                         Error_UnexpectedDirective ("no #if for this #endif");
2195                                         return true;
2196                                 } else {
2197                                         pop = (int) ifstack.Pop ();
2198
2199                                         if ((pop & REGION) != 0)
2200                                                 Report.Error (1038, Location, "#endregion directive expected");
2201
2202                                         if (arg.Length != 0) {
2203                                                 Error_EndLineExpected ();
2204                                         }
2205
2206                                         if (ifstack.Count == 0)
2207                                                 return true;
2208
2209                                         int state = (int) ifstack.Peek ();
2210                                         return (state & TAKING) != 0;
2211                                 }
2212
2213                         case "elif":
2214                                 if (ifstack == null || ifstack.Count == 0){
2215                                         Error_UnexpectedDirective ("no #if for this #elif");
2216                                         return true;
2217                                 } else {
2218                                         int state = (int) ifstack.Pop ();
2219
2220                                         if ((state & REGION) != 0) {
2221                                                 Report.Error (1038, Location, "#endregion directive expected");
2222                                                 return true;
2223                                         }
2224
2225                                         if ((state & ELSE_SEEN) != 0){
2226                                                 Error_UnexpectedDirective ("#elif not valid after #else");
2227                                                 return true;
2228                                         }
2229
2230                                         if ((state & TAKING) != 0) {
2231                                                 ifstack.Push (0);
2232                                                 return false;
2233                                         }
2234
2235                                         if (eval (arg) && ((state & PARENT_TAKING) != 0)){
2236                                                 ifstack.Push (state | TAKING);
2237                                                 return true;
2238                                         }
2239
2240                                         ifstack.Push (state);
2241                                         return false;
2242                                 }
2243
2244                         case "else":
2245                                 if (ifstack == null || ifstack.Count == 0){
2246                                         Error_UnexpectedDirective ("no #if for this #else");
2247                                         return true;
2248                                 } else {
2249                                         int state = (int) ifstack.Peek ();
2250
2251                                         if ((state & REGION) != 0) {
2252                                                 Report.Error (1038, Location, "#endregion directive expected");
2253                                                 return true;
2254                                         }
2255
2256                                         if ((state & ELSE_SEEN) != 0){
2257                                                 Error_UnexpectedDirective ("#else within #else");
2258                                                 return true;
2259                                         }
2260
2261                                         ifstack.Pop ();
2262
2263                                         if (arg.Length != 0) {
2264                                                 Error_EndLineExpected ();
2265                                                 return true;
2266                                         }
2267
2268                                         bool ret = false;
2269                                         if ((state & PARENT_TAKING) != 0) {
2270                                                 ret = (state & TAKING) == 0;
2271
2272                                                 if (ret)
2273                                                         state |= TAKING;
2274                                                 else
2275                                                         state &= ~TAKING;
2276                                         }
2277
2278                                         ifstack.Push (state | ELSE_SEEN);
2279
2280                                         return ret;
2281                                 }
2282                                 case "define":
2283                                         if (any_token_seen){
2284                                                 Error_TokensSeen ();
2285                                                 return caller_is_taking;
2286                                         }
2287                                         PreProcessDefinition (true, arg, caller_is_taking);
2288                                         return caller_is_taking;
2289
2290                                 case "undef":
2291                                         if (any_token_seen){
2292                                                 Error_TokensSeen ();
2293                                                 return caller_is_taking;
2294                                         }
2295                                         PreProcessDefinition (false, arg, caller_is_taking);
2296                                         return caller_is_taking;
2297                         }
2298
2299                         //
2300                         // These are only processed if we are in a `taking' block
2301                         //
2302                         if (!caller_is_taking)
2303                                 return false;
2304
2305                         switch (cmd){
2306                         case "error":
2307                                 Report.Error (1029, Location, "#error: '" + arg + "'");
2308                                 return true;
2309
2310                         case "warning":
2311                                 Report.Warning (1030, 1, Location, "#warning: `{0}'", arg);
2312                                 return true;
2313
2314                         case "pragma":
2315                                 if (RootContext.Version == LanguageVersion.ISO_1) {
2316                                         Report.FeatureIsNotAvailable (Location, "#pragma");
2317                                         return true;
2318                                 }
2319
2320                                 PreProcessPragma (arg);
2321                                 return true;
2322
2323                         case "line":
2324                                 if (!PreProcessLine (arg))
2325                                         Report.Error (
2326                                                 1576, Location,
2327                                                 "The line number specified for #line directive is missing or invalid");
2328                                 return caller_is_taking;
2329                         }
2330
2331                         Report.Error (1024, Location, "Wrong preprocessor directive");
2332                         return true;
2333
2334                 }
2335
2336                 private int consume_string (bool quoted)
2337                 {
2338                         int c;
2339                         string_builder.Length = 0;
2340
2341                         //
2342                         // No need to parse full string when parsing lambda arguments
2343                         //
2344                         if (lambda_arguments_parsing)
2345                                 return Token.LITERAL_STRING;
2346
2347                         while ((c = get_char ()) != -1){
2348                                 if (c == '"'){
2349                                         if (quoted && peek_char () == '"'){
2350                                                 string_builder.Append ((char) c);
2351                                                 get_char ();
2352                                                 continue;
2353                                         } else {
2354                                                 val = string_builder.ToString ();
2355                                                 return Token.LITERAL_STRING;
2356                                         }
2357                                 }
2358
2359                                 if (c == '\n'){
2360                                         if (!quoted)
2361                                                 Report.Error (1010, Location, "Newline in constant");
2362                                 }
2363
2364                                 if (!quoted){
2365                                         c = escape (c);
2366                                         if (c == -1)
2367                                                 return Token.ERROR;
2368                                 }
2369                                 string_builder.Append ((char) c);
2370                         }
2371
2372                         Report.Error (1039, Location, "Unterminated string literal");
2373                         return Token.EOF;
2374                 }
2375
2376                 private int consume_identifier (int s)
2377                 {
2378                         int res = consume_identifier (s, false);
2379
2380                         if (doc_state == XmlCommentState.Allowed)
2381                                 doc_state = XmlCommentState.NotAllowed;
2382                         switch (res) {
2383                         case Token.USING:
2384                         case Token.NAMESPACE:
2385                                 check_incorrect_doc_comment ();
2386                                 break;
2387                         }
2388
2389                         if (res == Token.PARTIAL) {
2390                                 if (parsing_block > 0) {
2391                                         val = new LocatedToken (Location, "partial");
2392                                         return Token.IDENTIFIER;
2393                                 }
2394
2395                                 // Save current position and parse next token.
2396                                 PushPosition ();
2397
2398                                 int next_token = token ();
2399                                 bool ok = (next_token == Token.CLASS) ||
2400                                         (next_token == Token.STRUCT) ||
2401                                         (next_token == Token.INTERFACE) ||
2402                                         (next_token == Token.VOID);
2403
2404                                 PopPosition ();
2405
2406                                 if (ok) {
2407                                         if (next_token == Token.VOID) {
2408                                                 if (RootContext.Version <= LanguageVersion.ISO_2)
2409                                                         Report.FeatureIsNotAvailable (Location, "partial methods");
2410                                         } else if (RootContext.Version == LanguageVersion.ISO_1)
2411                                                 Report.FeatureIsNotAvailable (Location, "partial types");
2412
2413                                         return res;
2414                                 }
2415
2416                                 if (next_token < Token.LAST_KEYWORD)
2417                                         Report.Error (267, Location, "The `partial' modifier can be used only immediately before `class', `struct', `interface', or `void' keyword");
2418
2419                                 val = new LocatedToken (Location, "partial");
2420                                 return Token.IDENTIFIER;
2421                         }
2422
2423                         return res;
2424                 }
2425
2426                 private int consume_identifier (int s, bool quoted)
2427                 {
2428                         int pos = 1;
2429                         int c = -1;
2430
2431                         id_builder [0] = (char) s;
2432
2433                         current_location = new Location (ref_line, hidden ? -1 : Col);
2434
2435                         while ((c = get_char ()) != -1) {
2436                         loop:
2437                                 if (is_identifier_part_character ((char) c)){
2438                                         if (pos == max_id_size){
2439                                                 Report.Error (645, Location, "Identifier too long (limit is 512 chars)");
2440                                                 return Token.ERROR;
2441                                         }
2442
2443                                         id_builder [pos++] = (char) c;
2444 //                                      putback_char = -1;
2445                                 } else if (c == '\\') {
2446                                         c = escape (c);
2447                                         goto loop;
2448                                 } else {
2449 //                                      putback_char = c;
2450                                         putback (c);
2451                                         break;
2452                                 }
2453                         }
2454
2455                         //
2456                         // Optimization: avoids doing the keyword lookup
2457                         // on uppercase letters and _
2458                         //
2459                         if (!quoted && (s >= 'a' || s == '_')){
2460                                 int keyword = GetKeyword (id_builder, pos);
2461                                 if (keyword != -1) {
2462                                         val = Location;
2463                                         return keyword;
2464                                 }
2465                         }
2466
2467                         //
2468                         // Keep identifiers in an array of hashtables to avoid needless
2469                         // allocations
2470                         //
2471
2472                         if (identifiers [pos] != null) {
2473                                 val = identifiers [pos][id_builder];
2474                                 if (val != null) {
2475                                         val = new LocatedToken (Location, (string) val);
2476                                         if (quoted)
2477                                                 escaped_identifiers.Add (val);
2478                                         return Token.IDENTIFIER;
2479                                 }
2480                         }
2481                         else
2482                                 identifiers [pos] = new CharArrayHashtable (pos);
2483
2484                         val = new String (id_builder, 0, pos);
2485                         if (RootContext.Version == LanguageVersion.ISO_1) {
2486                                 for (int i = 1; i < id_builder.Length; i += 3) {
2487                                         if (id_builder [i] == '_' && (id_builder [i - 1] == '_' || id_builder [i + 1] == '_')) {
2488                                                 Report.Error (1638, Location,
2489                                                         "`{0}': Any identifier with double underscores cannot be used when ISO language version mode is specified", val.ToString ());
2490                                                 break;
2491                                         }
2492                                 }
2493                         }
2494
2495                         char [] chars = new char [pos];
2496                         Array.Copy (id_builder, chars, pos);
2497
2498                         identifiers [pos] [chars] = val;
2499
2500                         val = new LocatedToken (Location, (string) val);
2501                         if (quoted)
2502                                 escaped_identifiers.Add (val);
2503                         return Token.IDENTIFIER;
2504                 }
2505
2506                 public int xtoken ()
2507                 {
2508                         int t;
2509                         bool doread = false;
2510                         int c;
2511
2512                         // Whether we have seen comments on the current line
2513                         bool comments_seen = false;
2514                         val = null;
2515                         for (;(c = get_char ()) != -1;) {
2516                                 if (c == '\t'){
2517                                         col = ((col + 8) / 8) * 8;
2518                                         continue;
2519                                 }
2520
2521                                 if (c == ' ' || c == '\f' || c == '\v' || c == 0xa0 || c == 0)
2522                                         continue;
2523
2524                                 if (c == '\r') {
2525                                         if (peek_char () != '\n')
2526                                                 advance_line ();
2527                                         else
2528                                                 get_char ();
2529
2530                                         any_token_seen |= tokens_seen;
2531                                         tokens_seen = false;
2532                                         comments_seen = false;
2533                                         continue;
2534                                 }
2535
2536                                 // Handle double-slash comments.
2537                                 if (c == '/'){
2538                                         int d = peek_char ();
2539
2540                                         if (d == '/'){
2541                                                 get_char ();
2542                                                 if (RootContext.Documentation != null && peek_char () == '/') {
2543                                                         get_char ();
2544                                                         // Don't allow ////.
2545                                                         if ((d = peek_char ()) != '/') {
2546                                                                 update_comment_location ();
2547                                                                 if (doc_state == XmlCommentState.Allowed)
2548                                                                         handle_one_line_xml_comment ();
2549                                                                 else if (doc_state == XmlCommentState.NotAllowed)
2550                                                                         warn_incorrect_doc_comment ();
2551                                                         }
2552                                                 }
2553                                                 while ((d = get_char ()) != -1 && (d != '\n') && d != '\r');
2554
2555                                                 any_token_seen |= tokens_seen;
2556                                                 tokens_seen = false;
2557                                                 comments_seen = false;
2558                                                 continue;
2559                                         } else if (d == '*'){
2560                                                 get_char ();
2561                                                 bool docAppend = false;
2562                                                 if (RootContext.Documentation != null && peek_char () == '*') {
2563                                                         get_char ();
2564                                                         update_comment_location ();
2565                                                         // But when it is /**/, just do nothing.
2566                                                         if (peek_char () == '/') {
2567                                                                 get_char ();
2568                                                                 continue;
2569                                                         }
2570                                                         if (doc_state == XmlCommentState.Allowed)
2571                                                                 docAppend = true;
2572                                                         else if (doc_state == XmlCommentState.NotAllowed)
2573                                                                 warn_incorrect_doc_comment ();
2574                                                 }
2575
2576                                                 int current_comment_start = 0;
2577                                                 if (docAppend) {
2578                                                         current_comment_start = xml_comment_buffer.Length;
2579                                                         xml_comment_buffer.Append (Environment.NewLine);
2580                                                 }
2581
2582                                                 Location start_location = Location;
2583
2584                                                 while ((d = get_char ()) != -1){
2585                                                         if (d == '*' && peek_char () == '/'){
2586                                                                 get_char ();
2587                                                                 comments_seen = true;
2588                                                                 break;
2589                                                         }
2590                                                         if (docAppend)
2591                                                                 xml_comment_buffer.Append ((char) d);
2592
2593                                                         if (d == '\n'){
2594                                                                 any_token_seen |= tokens_seen;
2595                                                                 tokens_seen = false;
2596                                                                 //
2597                                                                 // Reset 'comments_seen' just to be consistent.
2598                                                                 // It doesn't matter either way, here.
2599                                                                 //
2600                                                                 comments_seen = false;
2601                                                         }
2602                                                 }
2603                                                 if (!comments_seen)
2604                                                         Report.Error (1035, start_location, "End-of-file found, '*/' expected");
2605
2606                                                 if (docAppend)
2607                                                         update_formatted_doc_comment (current_comment_start);
2608                                                 continue;
2609                                         }
2610                                         goto is_punct_label;
2611                                 }
2612
2613
2614                                 if (c == '\\' || is_identifier_start_character ((char)c)){
2615                                         tokens_seen = true;
2616                                         return consume_identifier (c);
2617                                 }
2618
2619                         is_punct_label:
2620                                 current_location = new Location (ref_line, hidden ? -1 : Col);
2621                                 if ((t = is_punct ((char)c, ref doread)) != Token.ERROR){
2622                                         tokens_seen = true;
2623                                         if (doread){
2624                                                 get_char ();
2625                                         }
2626                                         return t;
2627                                 }
2628
2629                                 // white space
2630                                 if (c == '\n'){
2631                                         any_token_seen |= tokens_seen;
2632                                         tokens_seen = false;
2633                                         comments_seen = false;
2634                                         continue;
2635                                 }
2636
2637                                 if (c >= '0' && c <= '9'){
2638                                         tokens_seen = true;
2639                                         return is_number (c);
2640                                 }
2641
2642                                 if (c == '.'){
2643                                         tokens_seen = true;
2644                                         int peek = peek_char ();
2645                                         if (peek >= '0' && peek <= '9')
2646                                                 return is_number (c);
2647                                         return Token.DOT;
2648                                 }
2649
2650                                 if (c == '#') {
2651                                         if (tokens_seen || comments_seen) {
2652                                                 Eror_WrongPreprocessorLocation ();
2653                                                 return Token.ERROR;
2654                                         }
2655
2656                                         if (handle_preprocessing_directive (true))
2657                                                 continue;
2658
2659                                         bool directive_expected = false;
2660                                         while ((c = get_char ()) != -1) {
2661                                                 if (col == 1) {
2662                                                         directive_expected = true;
2663                                                 } else if (!directive_expected) {
2664                                                         // TODO: Implement comment support for disabled code and uncomment this code
2665 //                                                      if (c == '#') {
2666 //                                                              Eror_WrongPreprocessorLocation ();
2667 //                                                              return Token.ERROR;
2668 //                                                      }
2669                                                         continue;
2670                                                 }
2671
2672                                                 if (c == ' ' || c == '\t' || c == '\r' || c == '\n' || c == '\f' || c == '\v' )
2673                                                         continue;
2674
2675                                                 if (c == '#') {
2676                                                         if (handle_preprocessing_directive (false))
2677                                                                 break;
2678                                                 }
2679                                                 directive_expected = false;
2680                                         }
2681
2682                                         if (c != -1) {
2683                                                 tokens_seen = false;
2684                                                 continue;
2685                                         }
2686
2687                                         return Token.EOF;
2688                                 }
2689
2690                                 if (c == '"')
2691                                         return consume_string (false);
2692
2693                                 if (c == '\''){
2694                                         c = get_char ();
2695                                         tokens_seen = true;
2696                                         if (c == '\''){
2697                                                 error_details = "Empty character literal";
2698                                                 Report.Error (1011, Location, error_details);
2699                                                 return Token.ERROR;
2700                                         }
2701                                         if (c == '\r' || c == '\n') {
2702                                                 Report.Error (1010, Location, "Newline in constant");
2703                                                 return Token.ERROR;
2704                                         }
2705                                         c = escape (c);
2706                                         if (c == -1)
2707                                                 return Token.ERROR;
2708                                         val = new System.Char ();
2709                                         val = (char) c;
2710                                         c = get_char ();
2711
2712                                         if (c != '\''){
2713                                                 error_details = "Too many characters in character literal";
2714                                                 Report.Error (1012, Location, error_details);
2715
2716                                                 // Try to recover, read until newline or next "'"
2717                                                 while ((c = get_char ()) != -1){
2718                                                         if (c == '\n'){
2719                                                                 break;
2720                                                         }
2721                                                         else if (c == '\'')
2722                                                                 break;
2723                                                 }
2724                                                 return Token.ERROR;
2725                                         }
2726                                         return Token.LITERAL_CHARACTER;
2727                                 }
2728
2729                                 if (c == '@') {
2730                                         c = get_char ();
2731                                         if (c == '"') {
2732                                                 tokens_seen = true;
2733                                                 return consume_string (true);
2734                                         } else if (is_identifier_start_character ((char) c)){
2735                                                 return consume_identifier (c, true);
2736                                         } else {
2737                                                 Report.Error (1646, Location, "Keyword, identifier, or string expected after verbatim specifier: @");
2738                                         }
2739                                 }
2740
2741                                 error_details = ((char)c).ToString ();
2742
2743                                 return Token.ERROR;
2744                         }
2745
2746                         return Token.EOF;
2747                 }
2748
2749                 //
2750                 // Handles one line xml comment
2751                 //
2752                 private void handle_one_line_xml_comment ()
2753                 {
2754                         int c;
2755                         while ((c = peek_char ()) == ' ')
2756                                 get_char (); // skip heading whitespaces.
2757                         while ((c = peek_char ()) != -1 && c != '\n' && c != '\r') {
2758                                 xml_comment_buffer.Append ((char) get_char ());
2759                         }
2760                         if (c == '\r' || c == '\n')
2761                                 xml_comment_buffer.Append (Environment.NewLine);
2762                 }
2763
2764                 //
2765                 // Remove heading "*" in Javadoc-like xml documentation.
2766                 //
2767                 private void update_formatted_doc_comment (int current_comment_start)
2768                 {
2769                         int length = xml_comment_buffer.Length - current_comment_start;
2770                         string [] lines = xml_comment_buffer.ToString (
2771                                 current_comment_start,
2772                                 length).Replace ("\r", "").Split ('\n');
2773
2774                         // The first line starts with /**, thus it is not target
2775                         // for the format check.
2776                         for (int i = 1; i < lines.Length; i++) {
2777                                 string s = lines [i];
2778                                 int idx = s.IndexOf ('*');
2779                                 string head = null;
2780                                 if (idx < 0) {
2781                                         if (i < lines.Length - 1)
2782                                                 return;
2783                                         head = s;
2784                                 } else
2785                                         head = s.Substring (0, idx);
2786                                 foreach (char c in head)
2787                                         if (c != ' ')
2788                                                 return;
2789                                 lines [i] = s.Substring (idx + 1);
2790                         }
2791                         xml_comment_buffer.Remove (current_comment_start, length);
2792                         xml_comment_buffer.Insert (current_comment_start, String.Join (Environment.NewLine, lines));
2793                 }
2794
2795                 //
2796                 // Updates current comment location.
2797                 //
2798                 private void update_comment_location ()
2799                 {
2800                         if (current_comment_location.IsNull) {
2801                                 // "-2" is for heading "//" or "/*"
2802                                 current_comment_location =
2803                                         new Location (ref_line, hidden ? -1 : col - 2);
2804                         }
2805                 }
2806
2807                 //
2808                 // Checks if there was incorrect doc comments and raise
2809                 // warnings.
2810                 //
2811                 public void check_incorrect_doc_comment ()
2812                 {
2813                         if (xml_comment_buffer.Length > 0)
2814                                 warn_incorrect_doc_comment ();
2815                 }
2816
2817                 //
2818                 // Raises a warning when tokenizer found incorrect doccomment
2819                 // markup.
2820                 //
2821                 private void warn_incorrect_doc_comment ()
2822                 {
2823                         if (doc_state != XmlCommentState.Error) {
2824                                 doc_state = XmlCommentState.Error;
2825                                 // in csc, it is 'XML comment is not placed on
2826                                 // a valid language element'. But that does not
2827                                 // make sense.
2828                                 Report.Warning (1587, 2, Location, "XML comment is not placed on a valid language element");
2829                         }
2830                 }
2831
2832                 //
2833                 // Consumes the saved xml comment lines (if any)
2834                 // as for current target member or type.
2835                 //
2836                 public string consume_doc_comment ()
2837                 {
2838                         if (xml_comment_buffer.Length > 0) {
2839                                 string ret = xml_comment_buffer.ToString ();
2840                                 reset_doc_comment ();
2841                                 return ret;
2842                         }
2843                         return null;
2844                 }
2845
2846                 void reset_doc_comment ()
2847                 {
2848                         xml_comment_buffer.Length = 0;
2849                         current_comment_location = Location.Null;
2850                 }
2851
2852                 public void cleanup ()
2853                 {
2854                         if (ifstack != null && ifstack.Count >= 1) {
2855                                 current_location = new Location (ref_line, hidden ? -1 : Col);
2856                                 int state = (int) ifstack.Pop ();
2857                                 if ((state & REGION) != 0)
2858                                         Report.Error (1038, Location, "#endregion directive expected");
2859                                 else
2860                                         Report.Error (1027, Location, "Expected `#endif' directive");
2861                         }
2862                 }
2863         }
2864
2865         //
2866         // Indicates whether it accepts XML documentation or not.
2867         //
2868         public enum XmlCommentState {
2869                 // comment is allowed in this state.
2870                 Allowed,
2871                 // comment is not allowed in this state.
2872                 NotAllowed,
2873                 // once comments appeared when it is NotAllowed, then the
2874                 // state is changed to it, until the state is changed to
2875                 // .Allowed.
2876                 Error
2877         }
2878 }
2879