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 // Licensed under the terms of the GNU GPL
   9 //
  10 // (C) 2001, 2002 Ximian, Inc (http://www.ximian.com)
  11 // (C) 2004 Novell, Inc
  12 //
  13
  14 /*
  15  * TODO:
  16  *   Make sure we accept the proper Unicode ranges, per the spec.
  17  *   Report error 1032
  18 */
  19
  20 using System;
  21 using System.Text;
  22 using System.Collections;
  23 using System.IO;
  24 using System.Globalization;
  25 using System.Reflection;
  26
  27 namespace Mono.CSharp
  28 {
  29         /// <summary>
  30         ///    Tokenizer for C# source code.
  31         /// </summary>
  32
  33         public class Tokenizer : yyParser.yyInput
  34         {
  35                 SeekableStreamReader reader;
  36                 SourceFile ref_name;
  37                 SourceFile file_name;
  38                 int ref_line = 1;
  39                 int line = 1;
  40                 int col = 0;
  41                 int previous_col;
  42                 int current_token;
  43                 bool handle_get_set = false;
  44                 bool handle_remove_add = false;
  45                 bool handle_assembly = false;
  46                 Location current_location;
  47                 Location current_comment_location = Location.Null;
  48                 ArrayList escapedIdentifiers = new ArrayList ();
  49
  50                 //
  51                 // XML documentation buffer. The save point is used to divide
  52                 // comments on types and comments on members.
  53                 //
  54                 StringBuilder xml_comment_buffer;
  55
  56                 //
  57                 // See comment on XmlCommentState enumeration.
  58                 //
  59                 XmlCommentState xmlDocState = XmlCommentState.Allowed;
  60
  61                 //
  62                 // Whether tokens have been seen on this line
  63                 //
  64                 bool tokens_seen = false;
  65
  66                 //
  67                 // Whether a token has been seen on the file
  68                 // This is needed because `define' is not allowed to be used
  69                 // after a token has been seen.
  70                 //
  71                 bool any_token_seen = false;
  72
  73                 static Hashtable tokenValues;
  74
  75                 private static Hashtable TokenValueName
  76                 {
  77                         get {
  78                                 if (tokenValues == null)
  79                                         tokenValues = GetTokenValueNameHash ();
  80
  81                                 return tokenValues;
  82                         }
  83                 }
  84
  85                 private static Hashtable GetTokenValueNameHash ()
  86                 {
  87                         Type t = typeof (Token);
  88                         FieldInfo [] fields = t.GetFields ();
  89                         Hashtable hash = new Hashtable ();
  90                         foreach (FieldInfo field in fields) {
  91                                 if (field.IsLiteral && field.IsStatic && field.FieldType == typeof (int))
  92                                         hash.Add (field.GetValue (null), field.Name);
  93                         }
  94                         return hash;
  95                 }
  96
  97                 //
  98                 // Returns a verbose representation of the current location
  99                 //
 100                 public string location {
 101                         get {
 102                                 string det;
 103
 104                                 if (current_token == Token.ERROR)
 105                                         det = "detail: " + error_details;
 106                                 else
 107                                         det = "";
 108
 109                                 // return "Line:     "+line+" Col: "+col + "\n" +
 110                                 //       "VirtLine: "+ref_line +
 111                                 //       " Token: "+current_token + " " + det;
 112                                 string current_token_name = TokenValueName [current_token] as string;
 113                                 if (current_token_name == null)
 114                                         current_token_name = current_token.ToString ();
 115
 116                                 return String.Format ("{0} ({1},{2}), Token: {3} {4}", ref_name.Name,
 117                                                                                        ref_line,
 118                                                                                        col,
 119                                                                                        current_token_name,
 120                                                                                        det);
 121                         }
 122                 }
 123
 124                 public bool PropertyParsing {
 125                         get {
 126                                 return handle_get_set;
 127                         }
 128
 129                         set {
 130                                 handle_get_set = value;
 131                         }
 132                 }
 133
 134                 public bool AssemblyTargetParsing {
 135                         get {
 136                                 return handle_assembly;
 137                         }
 138
 139                         set {
 140                                 handle_assembly = value;
 141                         }
 142                 }
 143
 144                 public bool EventParsing {
 145                         get {
 146                                 return handle_remove_add;
 147                         }
 148
 149                         set {
 150                                 handle_remove_add = value;
 151                         }
 152                 }
 153
 154                 public XmlCommentState doc_state {
 155                         get { return xmlDocState; }
 156                         set {
 157                                 if (value == XmlCommentState.Allowed) {
 158                                         check_incorrect_doc_comment ();
 159                                         reset_doc_comment ();
 160                                 }
 161                                 xmlDocState = value;
 162                         }
 163                 }
 164
 165                 public bool IsEscapedIdentifier (Location loc)
 166                 {
 167                         foreach (LocatedToken lt in escapedIdentifiers)
 168                                 if (lt.Location.Equals (loc))
 169                                         return true;
 170                         return false;
 171                 }
 172
 173
 174                 //
 175                 // Class variables
 176                 //
 177                 static CharArrayHashtable[] keywords;
 178                 static Hashtable keywordStrings = new Hashtable ();
 179                 static NumberStyles styles;
 180                 static NumberFormatInfo csharp_format_info;
 181
 182                 //
 183                 // Values for the associated token returned
 184                 //
 185                 int putback_char;
 186                 Object val;
 187
 188                 //
 189                 // Pre-processor
 190                 //
 191                 Hashtable defines;
 192
 193                 const int TAKING        = 1;
 194                 const int TAKEN_BEFORE  = 2;
 195                 const int ELSE_SEEN     = 4;
 196                 const int PARENT_TAKING = 8;
 197                 const int REGION        = 16;
 198
 199                 //
 200                 // pre-processor if stack state:
 201                 //
 202                 Stack ifstack;
 203
 204                 static System.Text.StringBuilder string_builder;
 205
 206                 const int max_id_size = 512;
 207                 static char [] id_builder = new char [max_id_size];
 208
 209                 static CharArrayHashtable [] identifiers = new CharArrayHashtable [max_id_size + 1];
 210
 211                 const int max_number_size = 512;
 212                 static char [] number_builder = new char [max_number_size];
 213                 static int number_pos;
 214
 215                 //
 216                 // Details about the error encoutered by the tokenizer
 217                 //
 218                 string error_details;
 219
 220                 public string error {
 221                         get {
 222                                 return error_details;
 223                         }
 224                 }
 225
 226                 public int Line {
 227                         get {
 228                                 return ref_line;
 229                         }
 230                 }
 231
 232                 public int Col {
 233                         get {
 234                                 return col;
 235                         }
 236                 }
 237
 238                 static void AddKeyword (string kw, int token) {
 239                         keywordStrings.Add (kw, kw);
 240                         if (keywords [kw.Length] == null) {
 241                                 keywords [kw.Length] = new CharArrayHashtable (kw.Length);
 242                         }
 243                         keywords [kw.Length] [kw.ToCharArray ()] = token;
 244                 }
 245
 246                 static void InitTokens ()
 247                 {
 248                         keywords = new CharArrayHashtable [64];
 249
 250                         AddKeyword ("__arglist", Token.ARGLIST);
 251                         AddKeyword ("abstract", Token.ABSTRACT);
 252                         AddKeyword ("as", Token.AS);
 253                         AddKeyword ("add", Token.ADD);
 254                         AddKeyword ("assembly", Token.ASSEMBLY);
 255                         AddKeyword ("base", Token.BASE);
 256                         AddKeyword ("bool", Token.BOOL);
 257                         AddKeyword ("break", Token.BREAK);
 258                         AddKeyword ("byte", Token.BYTE);
 259                         AddKeyword ("case", Token.CASE);
 260                         AddKeyword ("catch", Token.CATCH);
 261                         AddKeyword ("char", Token.CHAR);
 262                         AddKeyword ("checked", Token.CHECKED);
 263                         AddKeyword ("class", Token.CLASS);
 264                         AddKeyword ("const", Token.CONST);
 265                         AddKeyword ("continue", Token.CONTINUE);
 266                         AddKeyword ("decimal", Token.DECIMAL);
 267                         AddKeyword ("default", Token.DEFAULT);
 268                         AddKeyword ("delegate", Token.DELEGATE);
 269                         AddKeyword ("do", Token.DO);
 270                         AddKeyword ("double", Token.DOUBLE);
 271                         AddKeyword ("else", Token.ELSE);
 272                         AddKeyword ("enum", Token.ENUM);
 273                         AddKeyword ("event", Token.EVENT);
 274                         AddKeyword ("explicit", Token.EXPLICIT);
 275                         AddKeyword ("extern", Token.EXTERN);
 276                         AddKeyword ("false", Token.FALSE);
 277                         AddKeyword ("finally", Token.FINALLY);
 278                         AddKeyword ("fixed", Token.FIXED);
 279                         AddKeyword ("float", Token.FLOAT);
 280                         AddKeyword ("for", Token.FOR);
 281                         AddKeyword ("foreach", Token.FOREACH);
 282                         AddKeyword ("goto", Token.GOTO);
 283                         AddKeyword ("get", Token.GET);
 284                         AddKeyword ("if", Token.IF);
 285                         AddKeyword ("implicit", Token.IMPLICIT);
 286                         AddKeyword ("in", Token.IN);
 287                         AddKeyword ("int", Token.INT);
 288                         AddKeyword ("interface", Token.INTERFACE);
 289                         AddKeyword ("internal", Token.INTERNAL);
 290                         AddKeyword ("is", Token.IS);
 291                         AddKeyword ("lock", Token.LOCK);
 292                         AddKeyword ("long", Token.LONG);
 293                         AddKeyword ("namespace", Token.NAMESPACE);
 294                         AddKeyword ("new", Token.NEW);
 295                         AddKeyword ("null", Token.NULL);
 296                         AddKeyword ("object", Token.OBJECT);
 297                         AddKeyword ("operator", Token.OPERATOR);
 298                         AddKeyword ("out", Token.OUT);
 299                         AddKeyword ("override", Token.OVERRIDE);
 300                         AddKeyword ("params", Token.PARAMS);
 301                         AddKeyword ("private", Token.PRIVATE);
 302                         AddKeyword ("protected", Token.PROTECTED);
 303                         AddKeyword ("public", Token.PUBLIC);
 304                         AddKeyword ("readonly", Token.READONLY);
 305                         AddKeyword ("ref", Token.REF);
 306                         AddKeyword ("remove", Token.REMOVE);
 307                         AddKeyword ("return", Token.RETURN);
 308                         AddKeyword ("sbyte", Token.SBYTE);
 309                         AddKeyword ("sealed", Token.SEALED);
 310                         AddKeyword ("set", Token.SET);
 311                         AddKeyword ("short", Token.SHORT);
 312                         AddKeyword ("sizeof", Token.SIZEOF);
 313                         AddKeyword ("stackalloc", Token.STACKALLOC);
 314                         AddKeyword ("static", Token.STATIC);
 315                         AddKeyword ("string", Token.STRING);
 316                         AddKeyword ("struct", Token.STRUCT);
 317                         AddKeyword ("switch", Token.SWITCH);
 318                         AddKeyword ("this", Token.THIS);
 319                         AddKeyword ("throw", Token.THROW);
 320                         AddKeyword ("true", Token.TRUE);
 321                         AddKeyword ("try", Token.TRY);
 322                         AddKeyword ("typeof", Token.TYPEOF);
 323                         AddKeyword ("uint", Token.UINT);
 324                         AddKeyword ("ulong", Token.ULONG);
 325                         AddKeyword ("unchecked", Token.UNCHECKED);
 326                         AddKeyword ("unsafe", Token.UNSAFE);
 327                         AddKeyword ("ushort", Token.USHORT);
 328                         AddKeyword ("using", Token.USING);
 329                         AddKeyword ("virtual", Token.VIRTUAL);
 330                         AddKeyword ("void", Token.VOID);
 331                         AddKeyword ("volatile", Token.VOLATILE);
 332                         AddKeyword ("while", Token.WHILE);
 333                         AddKeyword ("partial", Token.PARTIAL);
 334                 }
 335
 336                 //
 337                 // Class initializer
 338                 //
 339                 static Tokenizer ()
 340                 {
 341                         InitTokens ();
 342                         csharp_format_info = NumberFormatInfo.InvariantInfo;
 343                         styles = NumberStyles.Float;
 344
 345                         string_builder = new System.Text.StringBuilder ();
 346                 }
 347
 348                 int GetKeyword (char[] id, int id_len)
 349                 {
 350                         /*
 351                          * Keywords are stored in an array of hashtables grouped by their
 352                          * length.
 353                          */
 354
 355                         if ((id_len >= keywords.Length) || (keywords [id_len] == null))
 356                                 return -1;
 357                         object o = keywords [id_len] [id];
 358
 359                         if (o == null)
 360                                 return -1;
 361
 362                         int res = (int) o;
 363
 364                         if (handle_get_set == false && (res == Token.GET || res == Token.SET))
 365                                 return -1;
 366                         if (handle_remove_add == false && (res == Token.REMOVE || res == Token.ADD))
 367                                 return -1;
 368                         if (handle_assembly == false && res == Token.ASSEMBLY)
 369                                 return -1;
 370
 371                         return res;
 372
 373                 }
 374
 375                 public Location Location {
 376                         get { return current_location; }
 377                 }
 378
 379                 void define (string def)
 380                 {
 381                         if (!RootContext.AllDefines.Contains (def)){
 382                                 RootContext.AllDefines [def] = true;
 383                         }
 384                         if (defines.Contains (def))
 385                                 return;
 386                         defines [def] = true;
 387                 }
 388
 389                 public Tokenizer (SeekableStreamReader input, SourceFile file, ArrayList defs)
 390                 {
 391                         this.ref_name = file;
 392                         this.file_name = file;
 393                         reader = input;
 394
 395                         putback_char = -1;
 396
 397                         if (defs != null){
 398                                 defines = new Hashtable ();
 399                                 foreach (string def in defs)
 400                                         define (def);
 401                         }
 402
 403                         xml_comment_buffer = new StringBuilder ();
 404
 405                         //
 406                         // FIXME: This could be `Location.Push' but we have to
 407                         // find out why the MS compiler allows this
 408                         //
 409                         Mono.CSharp.Location.Push (file);
 410                 }
 411
 412                 static bool is_identifier_start_character (char c)
 413                 {
 414                         return (c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z') || c == '_' || Char.IsLetter (c);
 415                 }
 416
 417                 static bool is_identifier_part_character (char c)
 418                 {
 419                         return (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || c == '_' || (c >= '0' && c <= '9') || Char.IsLetter (c);
 420                 }
 421
 422                 public static bool IsKeyword (string s)
 423                 {
 424                         return keywordStrings [s] != null;
 425                 }
 426
 427                 public static bool IsValidIdentifier (string s)
 428                 {
 429                         if (s == null || s.Length == 0)
 430                                 return false;
 431
 432                         if (!is_identifier_start_character (s [0]))
 433                                 return false;
 434
 435                         for (int i = 1; i < s.Length; i ++)
 436                                 if (! is_identifier_part_character (s [i]))
 437                                         return false;
 438
 439                         return true;
 440                 }
 441
 442                 int is_punct (char c, ref bool doread)
 443                 {
 444                         int d;
 445                         int t;
 446
 447                         doread = false;
 448
 449                         switch (c){
 450                         case '{':
 451                                 val = Location;
 452                                 return Token.OPEN_BRACE;
 453                         case '}':
 454                                 val = Location;
 455                                 return Token.CLOSE_BRACE;
 456                         case '[':
 457                                 // To block doccomment inside attribute declaration.
 458                                 if (doc_state == XmlCommentState.Allowed)
 459                                         doc_state = XmlCommentState.NotAllowed;
 460                                 return Token.OPEN_BRACKET;
 461                         case ']':
 462                                 return Token.CLOSE_BRACKET;
 463                         case '(':
 464                                 return Token.OPEN_PARENS;
 465                         case ')': {
 466                                 if (deambiguate_close_parens == 0)
 467                                         return Token.CLOSE_PARENS;
 468
 469                                 --deambiguate_close_parens;
 470
 471                                 // Save current position and parse next token.
 472                                 int old = reader.Position;
 473                                 int old_ref_line = ref_line;
 474                                 int old_col = col;
 475
 476                                 // disable preprocessing directives when peeking
 477                                 process_directives = false;
 478                                 int new_token = token ();
 479                                 process_directives = true;
 480                                 reader.Position = old;
 481                                 ref_line = old_ref_line;
 482                                 col = old_col;
 483                                 putback_char = -1;
 484
 485                                 if (new_token == Token.OPEN_PARENS)
 486                                         return Token.CLOSE_PARENS_OPEN_PARENS;
 487                                 else if (new_token == Token.MINUS)
 488                                         return Token.CLOSE_PARENS_MINUS;
 489                                 else if (IsCastToken (new_token))
 490                                         return Token.CLOSE_PARENS_CAST;
 491                                 else
 492                                         return Token.CLOSE_PARENS_NO_CAST;
 493                         }
 494
 495                         case ',':
 496                                 return Token.COMMA;
 497                         case ';':
 498                                 val = Location;
 499                                 return Token.SEMICOLON;
 500                         case '~':
 501                                 val = Location;
 502                                 return Token.TILDE;
 503                         case '?':
 504                                 return Token.INTERR;
 505                         }
 506
 507                         d = peekChar ();
 508                         if (c == '+'){
 509
 510                                 if (d == '+') {
 511                                         val = Location;
 512                                         t = Token.OP_INC;
 513                                 }
 514                                 else if (d == '=')
 515                                         t = Token.OP_ADD_ASSIGN;
 516                                 else {
 517                                         val = Location;
 518                                         return Token.PLUS;
 519                                 }
 520                                 doread = true;
 521                                 return t;
 522                         }
 523                         if (c == '-'){
 524                                 if (d == '-') {
 525                                         val = Location;
 526                                         t = Token.OP_DEC;
 527                                 }
 528                                 else if (d == '=')
 529                                         t = Token.OP_SUB_ASSIGN;
 530                                 else if (d == '>')
 531                                         t = Token.OP_PTR;
 532                                 else {
 533                                         val = Location;
 534                                         return Token.MINUS;
 535                                 }
 536                                 doread = true;
 537                                 return t;
 538                         }
 539
 540                         if (c == '!'){
 541                                 if (d == '='){
 542                                         doread = true;
 543                                         return Token.OP_NE;
 544                                 }
 545                                 val = Location;
 546                                 return Token.BANG;
 547                         }
 548
 549                         if (c == '='){
 550                                 if (d == '='){
 551                                         doread = true;
 552                                         return Token.OP_EQ;
 553                                 }
 554                                 return Token.ASSIGN;
 555                         }
 556
 557                         if (c == '&'){
 558                                 if (d == '&'){
 559                                         doread = true;
 560                                         return Token.OP_AND;
 561                                 } else if (d == '='){
 562                                         doread = true;
 563                                         return Token.OP_AND_ASSIGN;
 564                                 }
 565                                 val = Location;
 566                                 return Token.BITWISE_AND;
 567                         }
 568
 569                         if (c == '|'){
 570                                 if (d == '|'){
 571                                         doread = true;
 572                                         return Token.OP_OR;
 573                                 } else if (d == '='){
 574                                         doread = true;
 575                                         return Token.OP_OR_ASSIGN;
 576                                 }
 577                                 return Token.BITWISE_OR;
 578                         }
 579
 580                         if (c == '*'){
 581                                 if (d == '='){
 582                                         doread = true;
 583                                         return Token.OP_MULT_ASSIGN;
 584                                 }
 585                                 val = Location;
 586                                 return Token.STAR;
 587                         }
 588
 589                         if (c == '/'){
 590                                 if (d == '='){
 591                                         doread = true;
 592                                         return Token.OP_DIV_ASSIGN;
 593                                 }
 594                                 return Token.DIV;
 595                         }
 596
 597                         if (c == '%'){
 598                                 if (d == '='){
 599                                         doread = true;
 600                                         return Token.OP_MOD_ASSIGN;
 601                                 }
 602                                 return Token.PERCENT;
 603                         }
 604
 605                         if (c == '^'){
 606                                 if (d == '='){
 607                                         doread = true;
 608                                         return Token.OP_XOR_ASSIGN;
 609                                 }
 610                                 return Token.CARRET;
 611                         }
 612
 613                         if (c == '<'){
 614                                 if (d == '<'){
 615                                         getChar ();
 616                                         d = peekChar ();
 617
 618                                         if (d == '='){
 619                                                 doread = true;
 620                                                 return Token.OP_SHIFT_LEFT_ASSIGN;
 621                                         }
 622                                         return Token.OP_SHIFT_LEFT;
 623                                 } else if (d == '='){
 624                                         doread = true;
 625                                         return Token.OP_LE;
 626                                 }
 627                                 return Token.OP_LT;
 628                         }
 629
 630                         if (c == '>'){
 631                                 if (d == '>'){
 632                                         getChar ();
 633                                         d = peekChar ();
 634
 635                                         if (d == '='){
 636                                                 doread = true;
 637                                                 return Token.OP_SHIFT_RIGHT_ASSIGN;
 638                                         }
 639                                         return Token.OP_SHIFT_RIGHT;
 640                                 } else if (d == '='){
 641                                         doread = true;
 642                                         return Token.OP_GE;
 643                                 }
 644                                 return Token.OP_GT;
 645                         }
 646                         if (c == ':'){
 647                                 if (d == ':'){
 648                                         doread = true;
 649                                         return Token.DOUBLE_COLON;
 650                                 }
 651                                 val = Location;
 652                                 return Token.COLON;
 653                         }
 654
 655                         return Token.ERROR;
 656                 }
 657
 658                 int deambiguate_close_parens = 0;
 659
 660                 public void Deambiguate_CloseParens (object expression)
 661                 {
 662                         putback (')');
 663
 664                         // When any binary operation is used we are sure it is not a cast
 665                         if (expression is Binary)
 666                                 return;
 667
 668                         deambiguate_close_parens++;
 669                 }
 670
 671                 void Error_NumericConstantTooLong ()
 672                 {
 673                         Report.Error (1021, Location, "Numeric constant too long");
 674                 }
 675
 676                 bool decimal_digits (int c)
 677                 {
 678                         int d;
 679                         bool seen_digits = false;
 680
 681                         if (c != -1){
 682                                 if (number_pos == max_number_size)
 683                                         Error_NumericConstantTooLong ();
 684                                 number_builder [number_pos++] = (char) c;
 685                         }
 686
 687                         //
 688                         // We use peekChar2, because decimal_digits needs to do a
 689                         // 2-character look-ahead (5.ToString for example).
 690                         //
 691                         while ((d = peekChar2 ()) != -1){
 692                                 if (d >= '0' && d <= '9'){
 693                                         if (number_pos == max_number_size)
 694                                                 Error_NumericConstantTooLong ();
 695                                         number_builder [number_pos++] = (char) d;
 696                                         getChar ();
 697                                         seen_digits = true;
 698                                 } else
 699                                         break;
 700                         }
 701
 702                         return seen_digits;
 703                 }
 704
 705                 static bool is_hex (int e)
 706                 {
 707                         return (e >= '0' && e <= '9') || (e >= 'A' && e <= 'F') || (e >= 'a' && e <= 'f');
 708                 }
 709
 710                 static int real_type_suffix (int c)
 711                 {
 712                         int t;
 713
 714                         switch (c){
 715                         case 'F': case 'f':
 716                                 t =  Token.LITERAL_FLOAT;
 717                                 break;
 718                         case 'D': case 'd':
 719                                 t = Token.LITERAL_DOUBLE;
 720                                 break;
 721                         case 'M': case 'm':
 722                                  t= Token.LITERAL_DECIMAL;
 723                                 break;
 724                         default:
 725                                 return Token.NONE;
 726                         }
 727                         return t;
 728                 }
 729
 730                 int integer_type_suffix (ulong ul, int c)
 731                 {
 732                         bool is_unsigned = false;
 733                         bool is_long = false;
 734
 735                         if (c != -1){
 736                                 bool scanning = true;
 737                                 do {
 738                                         switch (c){
 739                                         case 'U': case 'u':
 740                                                 if (is_unsigned)
 741                                                         scanning = false;
 742                                                 is_unsigned = true;
 743                                                 getChar ();
 744                                                 break;
 745
 746                                         case 'l':
 747                                                 if (!is_unsigned && (RootContext.WarningLevel >= 4)){
 748                                                         //
 749                                                         // if we have not seen anything in between
 750                                                         // report this error
 751                                                         //
 752                                                         Report.Warning (78, 4, Location, "The 'l' suffix is easily confused with the digit '1' (use 'L' for clarity)");
 753                                                 }
 754                                                 //
 755                                                 // This goto statement causes the MS CLR 2.0 beta 1 csc to report an error, so
 756                                                 // work around that.
 757                                                 //
 758                                                 //goto case 'L';
 759                                                 if (is_long)
 760                                                         scanning = false;
 761                                                 is_long = true;
 762                                                 getChar ();
 763                                                 break;
 764
 765                                         case 'L':
 766                                                 if (is_long)
 767                                                         scanning = false;
 768                                                 is_long = true;
 769                                                 getChar ();
 770                                                 break;
 771
 772                                         default:
 773                                                 scanning = false;
 774                                                 break;
 775                                         }
 776                                         c = peekChar ();
 777                                 } while (scanning);
 778                         }
 779
 780                         if (is_long && is_unsigned){
 781                                 val = ul;
 782                                 return Token.LITERAL_INTEGER;
 783                         } else if (is_unsigned){
 784                                 // uint if possible, or ulong else.
 785
 786                                 if ((ul & 0xffffffff00000000) == 0)
 787                                         val = (uint) ul;
 788                                 else
 789                                         val = ul;
 790                         } else if (is_long){
 791                                 // long if possible, ulong otherwise
 792                                 if ((ul & 0x8000000000000000) != 0)
 793                                         val = ul;
 794                                 else
 795                                         val = (long) ul;
 796                         } else {
 797                                 // int, uint, long or ulong in that order
 798                                 if ((ul & 0xffffffff00000000) == 0){
 799                                         uint ui = (uint) ul;
 800
 801                                         if ((ui & 0x80000000) != 0)
 802                                                 val = ui;
 803                                         else
 804                                                 val = (int) ui;
 805                                 } else {
 806                                         if ((ul & 0x8000000000000000) != 0)
 807                                                 val = ul;
 808                                         else
 809                                                 val = (long) ul;
 810                                 }
 811                         }
 812                         return Token.LITERAL_INTEGER;
 813                 }
 814
 815                 //
 816                 // given `c' as the next char in the input decide whether
 817                 // we need to convert to a special type, and then choose
 818                 // the best representation for the integer
 819                 //
 820                 int adjust_int (int c)
 821                 {
 822                         try {
 823                                 if (number_pos > 9){
 824                                         ulong ul = (uint) (number_builder [0] - '0');
 825
 826                                         for (int i = 1; i < number_pos; i++){
 827                                                 ul = checked ((ul * 10) + ((uint)(number_builder [i] - '0')));
 828                                         }
 829                                         return integer_type_suffix (ul, c);
 830                                 } else {
 831                                         uint ui = (uint) (number_builder [0] - '0');
 832
 833                                         for (int i = 1; i < number_pos; i++){
 834                                                 ui = checked ((ui * 10) + ((uint)(number_builder [i] - '0')));
 835                                         }
 836                                         return integer_type_suffix (ui, c);
 837                                 }
 838                         } catch (OverflowException) {
 839                                 error_details = "Integral constant is too large";
 840                                 Report.Error (1021, Location, error_details);
 841                                 val = 0ul;
 842                                 return Token.LITERAL_INTEGER;
 843                         }
 844                         catch (FormatException) {
 845                                 Report.Error (1013, Location, "Invalid number");
 846                                 val = 0ul;
 847                                 return Token.LITERAL_INTEGER;
 848                         }
 849                 }
 850
 851                 int adjust_real (int t)
 852                 {
 853                         string s = new String (number_builder, 0, number_pos);
 854                         const string error_details = "Floating-point constant is outside the range of type `{0}'";
 855
 856                         switch (t){
 857                         case Token.LITERAL_DECIMAL:
 858                                 try {
 859                                         val = System.Decimal.Parse (s, styles, csharp_format_info);
 860                                 } catch (OverflowException) {
 861                                         val = 0m;
 862                                         Report.Error (594, Location, error_details, "decimal");
 863                                 }
 864                                 break;
 865                         case Token.LITERAL_FLOAT:
 866                                 try {
 867                                         val = float.Parse (s, styles, csharp_format_info);
 868                                 } catch (OverflowException) {
 869                                         val = 0.0f;
 870                                         Report.Error (594, Location, error_details, "float");
 871                                 }
 872                                 break;
 873
 874                         case Token.LITERAL_DOUBLE:
 875                         case Token.NONE:
 876                                 t = Token.LITERAL_DOUBLE;
 877                                 try {
 878                                         val = System.Double.Parse (s, styles, csharp_format_info);
 879                                 } catch (OverflowException) {
 880                                         val = 0.0;
 881                                         Report.Error (594, Location, error_details, "double");
 882                                 }
 883                                 break;
 884                         }
 885                         return t;
 886                 }
 887
 888                 int handle_hex ()
 889                 {
 890                         int d;
 891                         ulong ul;
 892
 893                         getChar ();
 894                         while ((d = peekChar ()) != -1){
 895                                 if (is_hex (d)){
 896                                         number_builder [number_pos++] = (char) d;
 897                                         getChar ();
 898                                 } else
 899                                         break;
 900                         }
 901
 902                         string s = new String (number_builder, 0, number_pos);
 903                         try {
 904                                 if (number_pos <= 8)
 905                                         ul = System.UInt32.Parse (s, NumberStyles.HexNumber);
 906                                 else
 907                                         ul = System.UInt64.Parse (s, NumberStyles.HexNumber);
 908                         } catch (OverflowException){
 909                                 error_details = "Integral constant is too large";
 910                                 Report.Error (1021, Location, error_details);
 911                                 val = 0ul;
 912                                 return Token.LITERAL_INTEGER;
 913                         }
 914                         catch (FormatException) {
 915                                 Report.Error (1013, Location, "Invalid number");
 916                                 val = 0ul;
 917                                 return Token.LITERAL_INTEGER;
 918                         }
 919
 920                         return integer_type_suffix (ul, peekChar ());
 921                 }
 922
 923                 //
 924                 // Invoked if we know we have .digits or digits
 925                 //
 926                 int is_number (int c)
 927                 {
 928                         bool is_real = false;
 929                         int type;
 930
 931                         number_pos = 0;
 932
 933                         if (c >= '0' && c <= '9'){
 934                                 if (c == '0'){
 935                                         int peek = peekChar ();
 936
 937                                         if (peek == 'x' || peek == 'X')
 938                                                 return handle_hex ();
 939                                 }
 940                                 decimal_digits (c);
 941                                 c = getChar ();
 942                         }
 943
 944                         //
 945                         // We need to handle the case of
 946                         // "1.1" vs "1.string" (LITERAL_FLOAT vs NUMBER DOT IDENTIFIER)
 947                         //
 948                         if (c == '.'){
 949                                 if (decimal_digits ('.')){
 950                                         is_real = true;
 951                                         c = getChar ();
 952                                 } else {
 953                                         putback ('.');
 954                                         number_pos--;
 955                                         return adjust_int (-1);
 956                                 }
 957                         }
 958
 959                         if (c == 'e' || c == 'E'){
 960                                 is_real = true;
 961                                 if (number_pos == max_number_size)
 962                                         Error_NumericConstantTooLong ();
 963                                 number_builder [number_pos++] = 'e';
 964                                 c = getChar ();
 965
 966                                 if (c == '+'){
 967                                         if (number_pos == max_number_size)
 968                                                 Error_NumericConstantTooLong ();
 969                                         number_builder [number_pos++] = '+';
 970                                         c = -1;
 971                                 } else if (c == '-') {
 972                                         if (number_pos == max_number_size)
 973                                                 Error_NumericConstantTooLong ();
 974                                         number_builder [number_pos++] = '-';
 975                                         c = -1;
 976                                 } else {
 977                                         if (number_pos == max_number_size)
 978                                                 Error_NumericConstantTooLong ();
 979                                         number_builder [number_pos++] = '+';
 980                                 }
 981
 982                                 decimal_digits (c);
 983                                 c = getChar ();
 984                         }
 985
 986                         type = real_type_suffix (c);
 987                         if (type == Token.NONE && !is_real){
 988                                 putback (c);
 989                                 return adjust_int (c);
 990                         } else
 991                                 is_real = true;
 992
 993                         if (type == Token.NONE){
 994                                 putback (c);
 995                         }
 996
 997                         if (is_real)
 998                                 return adjust_real (type);
 999
1000                         Console.WriteLine ("This should not be reached");
1001                         throw new Exception ("Is Number should never reach this point");
1002                 }
1003
1004                 //
1005                 // Accepts exactly count (4 or 8) hex, no more no less
1006                 //
1007                 int getHex (int count, out bool error)
1008                 {
1009                         int i;
1010                         int total = 0;
1011                         int c;
1012                         int top = count != -1 ? count : 4;
1013
1014                         getChar ();
1015                         error = false;
1016                         for (i = 0; i < top; i++){
1017                                 c = getChar ();
1018
1019                                 if (c >= '0' && c <= '9')
1020                                         c = (int) c - (int) '0';
1021                                 else if (c >= 'A' && c <= 'F')
1022                                         c = (int) c - (int) 'A' + 10;
1023                                 else if (c >= 'a' && c <= 'f')
1024                                         c = (int) c - (int) 'a' + 10;
1025                                 else {
1026                                         error = true;
1027                                         return 0;
1028                                 }
1029
1030                                 total = (total * 16) + c;
1031                                 if (count == -1){
1032                                         int p = peekChar ();
1033                                         if (p == -1)
1034                                                 break;
1035                                         if (!is_hex ((char)p))
1036                                                 break;
1037                                 }
1038                         }
1039                         return total;
1040                 }
1041
1042                 int escape (int c)
1043                 {
1044                         bool error;
1045                         int d;
1046                         int v;
1047
1048                         d = peekChar ();
1049                         if (c != '\\')
1050                                 return c;
1051
1052                         switch (d){
1053                         case 'a':
1054                                 v = '\a'; break;
1055                         case 'b':
1056                                 v = '\b'; break;
1057                         case 'n':
1058                                 v = '\n'; break;
1059                         case 't':
1060                                 v = '\t'; break;
1061                         case 'v':
1062                                 v = '\v'; break;
1063                         case 'r':
1064                                 v = '\r'; break;
1065                         case '\\':
1066                                 v = '\\'; break;
1067                         case 'f':
1068                                 v = '\f'; break;
1069                         case '0':
1070                                 v = 0; break;
1071                         case '"':
1072                                 v = '"'; break;
1073                         case '\'':
1074                                 v = '\''; break;
1075                         case 'x':
1076                                 v = getHex (-1, out error);
1077                                 if (error)
1078                                         goto default;
1079                                 return v;
1080                         case 'u':
1081                                 v = getHex (4, out error);
1082                                 if (error)
1083                                         goto default;
1084                                 return v;
1085                         case 'U':
1086                                 v = getHex (8, out error);
1087                                 if (error)
1088                                         goto default;
1089                                 return v;
1090                         default:
1091                                 Report.Error (1009, Location, "Unrecognized escape sequence `\\{0}'", ((char)d).ToString ());
1092                                 return d;
1093                         }
1094                         getChar ();
1095                         return v;
1096                 }
1097
1098                 int getChar ()
1099                 {
1100                         int x;
1101                         if (putback_char != -1) {
1102                                 x = putback_char;
1103                                 putback_char = -1;
1104                         }
1105                         else
1106                                 x = reader.Read ();
1107                         if (x == '\n') {
1108                                 line++;
1109                                 ref_line++;
1110                                 previous_col = col;
1111                                 col = 0;
1112                         }
1113                         else
1114                                 col++;
1115                         return x;
1116                 }
1117
1118                 int peekChar ()
1119                 {
1120                         if (putback_char != -1)
1121                                 return putback_char;
1122                         putback_char = reader.Read ();
1123                         return putback_char;
1124                 }
1125
1126                 int peekChar2 ()
1127                 {
1128                         if (putback_char != -1)
1129                                 return putback_char;
1130                         return reader.Peek ();
1131                 }
1132
1133                 void putback (int c)
1134                 {
1135                         if (putback_char != -1){
1136                                 Console.WriteLine ("Col: " + col);
1137                                 Console.WriteLine ("Row: " + line);
1138                                 Console.WriteLine ("Name: " + ref_name.Name);
1139                                 Console.WriteLine ("Current [{0}] putting back [{1}]  ", putback_char, c);
1140                                 throw new Exception ("This should not happen putback on putback");
1141                         }
1142                         if (c == '\n' || col == 0) {
1143                                 // It won't happen though.
1144                                 line--;
1145                                 ref_line--;
1146                                 col = previous_col;
1147                         }
1148                         else
1149                                 col--;
1150                         putback_char = c;
1151                 }
1152
1153                 public bool advance ()
1154                 {
1155                         return peekChar () != -1;
1156                 }
1157
1158                 public Object Value {
1159                         get {
1160                                 return val;
1161                         }
1162                 }
1163
1164                 public Object value ()
1165                 {
1166                         return val;
1167                 }
1168
1169                 static bool IsCastToken (int token)
1170                 {
1171                         switch (token) {
1172                         case Token.BANG:
1173                         case Token.TILDE:
1174                         case Token.IDENTIFIER:
1175                         case Token.LITERAL_INTEGER:
1176                         case Token.LITERAL_FLOAT:
1177                         case Token.LITERAL_DOUBLE:
1178                         case Token.LITERAL_DECIMAL:
1179                         case Token.LITERAL_CHARACTER:
1180                         case Token.LITERAL_STRING:
1181                         case Token.BASE:
1182                         case Token.CHECKED:
1183                         case Token.FALSE:
1184                         case Token.FIXED:
1185                         case Token.NEW:
1186                         case Token.NULL:
1187                         case Token.SIZEOF:
1188                         case Token.THIS:
1189                         case Token.THROW:
1190                         case Token.TRUE:
1191                         case Token.TYPEOF:
1192                         case Token.UNCHECKED:
1193                         case Token.UNSAFE:
1194
1195                                 //
1196                                 // These can be part of a member access
1197                                 //
1198                         case Token.INT:
1199                         case Token.UINT:
1200                         case Token.SHORT:
1201                         case Token.USHORT:
1202                         case Token.LONG:
1203                         case Token.ULONG:
1204                         case Token.DOUBLE:
1205                         case Token.FLOAT:
1206                         case Token.CHAR:
1207                                 return true;
1208
1209                         default:
1210                                 return false;
1211                         }
1212                 }
1213
1214                 public int token ()
1215                 {
1216                         current_token = xtoken ();
1217                         return current_token;
1218                 }
1219
1220                 static StringBuilder static_cmd_arg = new System.Text.StringBuilder ();
1221
1222                 void get_cmd_arg (out string cmd, out string arg)
1223                 {
1224                         int c;
1225
1226                         tokens_seen = false;
1227                         arg = "";
1228                         static_cmd_arg.Length = 0;
1229
1230                         // skip over white space
1231                         while ((c = getChar ()) != -1 && (c != '\n') && ((c == '\r') || (c == ' ') || (c == '\t')))
1232                                 ;
1233
1234
1235                         while ((c != -1) && (c != '\n') && (c != ' ') && (c != '\t') && (c != '\r')){
1236                                 if (is_identifier_part_character ((char) c)){
1237                                         static_cmd_arg.Append ((char) c);
1238                                         c = getChar ();
1239                                 } else {
1240                                         putback (c);
1241                                         break;
1242                                 }
1243                         }
1244
1245                         cmd = static_cmd_arg.ToString ();
1246
1247                         if (c == '\n'){
1248                                 return;
1249                         }
1250
1251                         // skip over white space
1252                         while ((c = getChar ()) != -1 && (c != '\n') && ((c == '\r') || (c == ' ') || (c == '\t')))
1253                                 ;
1254
1255                         if (c == '\n'){
1256                                 return;
1257                         } else if (c == '\r'){
1258                                 return;
1259                         } else if (c == -1){
1260                                 arg = "";
1261                                 return;
1262                         }
1263
1264                         static_cmd_arg.Length = 0;
1265                         static_cmd_arg.Append ((char) c);
1266
1267                         while ((c = getChar ()) != -1 && (c != '\n') && (c != '\r')){
1268                                 static_cmd_arg.Append ((char) c);
1269                         }
1270
1271                         arg = static_cmd_arg.ToString ().Trim ();
1272                 }
1273
1274                 //
1275                 // Handles the #line directive
1276                 //
1277                 bool PreProcessLine (string arg)
1278                 {
1279                         if (arg.Length == 0)
1280                                 return false;
1281
1282                         if (arg == "default"){
1283                                 ref_line = line;
1284                                 ref_name = file_name;
1285                                 Location.Push (ref_name);
1286                                 return true;
1287                         } else if (arg == "hidden"){
1288                                 //
1289                                 // We ignore #line hidden
1290                                 //
1291                                 return true;
1292                         }
1293
1294                         try {
1295                                 int pos;
1296
1297                                 if ((pos = arg.IndexOf (' ')) != -1 && pos != 0){
1298                                         ref_line = System.Int32.Parse (arg.Substring (0, pos));
1299                                         pos++;
1300
1301                                         char [] quotes = { '\"' };
1302
1303                                         string name = arg.Substring (pos). Trim (quotes);
1304                                         ref_name = Location.LookupFile (name);
1305                                         file_name.HasLineDirective = true;
1306                                         ref_name.HasLineDirective = true;
1307                                         Location.Push (ref_name);
1308                                 } else {
1309                                         ref_line = System.Int32.Parse (arg);
1310                                 }
1311                         } catch {
1312                                 return false;
1313                         }
1314
1315                         return true;
1316                 }
1317
1318                 //
1319                 // Handles #define and #undef
1320                 //
1321                 void PreProcessDefinition (bool is_define, string arg)
1322                 {
1323                         if (arg.Length == 0 || arg == "true" || arg == "false"){
1324                                 Report.Error (1001, Location, "Missing identifer to pre-processor directive");
1325                                 return;
1326                         }
1327
1328                         char[] whitespace = { ' ', '\t' };
1329                         if (arg.IndexOfAny (whitespace) != -1){
1330                                 Report.Error (1025, Location, "Single-line comment or end-of-line expected");
1331                                 return;
1332                         }
1333
1334                         if (!is_identifier_start_character (arg [0]))
1335                                 Report.Error (1001, Location, "Identifier expected: " + arg);
1336
1337                         foreach (char c in arg.Substring (1)){
1338                                 if (!is_identifier_part_character (c)){
1339                                         Report.Error (1001, Location, "Identifier expected: " + arg);
1340                                         return;
1341                                 }
1342                         }
1343
1344                         if (is_define){
1345                                 if (defines == null)
1346                                         defines = new Hashtable ();
1347                                 define (arg);
1348                         } else {
1349                                 if (defines == null)
1350                                         return;
1351                                 if (defines.Contains (arg))
1352                                         defines.Remove (arg);
1353                         }
1354                 }
1355
1356                 /// <summary>
1357                 /// Handles #pragma directive
1358                 /// </summary>
1359                 void PreProcessPragma (string arg)
1360                 {
1361                         const string warning = "warning";
1362                         const string w_disable = "warning disable";
1363                         const string w_restore = "warning restore";
1364
1365                         if (arg == w_disable) {
1366                                 Report.RegisterWarningRegion (Location).WarningDisable (line);
1367                                 return;
1368                         }
1369
1370                         if (arg == w_restore) {
1371                                 Report.RegisterWarningRegion (Location).WarningEnable (line);
1372                                 return;
1373                         }
1374
1375                         if (arg.StartsWith (w_disable)) {
1376                                 int[] codes = ParseNumbers (arg.Substring (w_disable.Length));
1377                                 foreach (int code in codes) {
1378                                         if (code != 0)
1379                                                 Report.RegisterWarningRegion (Location).WarningDisable (Location, code);
1380                                 }
1381                                 return;
1382                         }
1383
1384                         if (arg.StartsWith (w_restore)) {
1385                                 int[] codes = ParseNumbers (arg.Substring (w_restore.Length));
1386                                 Hashtable w_table = Report.warning_ignore_table;
1387                                 foreach (int code in codes) {
1388                                         if (w_table != null && w_table.Contains (code))
1389                                                 Report.Warning (1635, 1, Location, String.Format ("Cannot restore warning `CS{0:0000}' because it was disabled globally", code));
1390                                         Report.RegisterWarningRegion (Location).WarningEnable (Location, code);
1391                                 }
1392                                 return;
1393                         }
1394
1395                         if (arg.StartsWith (warning)) {
1396                                 Report.Warning (1634, 1, Location, "Expected disable or restore");
1397                                 return;
1398                         }
1399
1400                         Report.Warning (1633, 1, Location, "Unrecognized #pragma directive");
1401                 }
1402
1403                 int[] ParseNumbers (string text)
1404                 {
1405                         string[] string_array = text.Split (',');
1406                         int[] values = new int [string_array.Length];
1407                         int index = 0;
1408                         foreach (string string_code in string_array) {
1409                                 try {
1410                                         values[index++] = int.Parse (string_code, System.Globalization.CultureInfo.InvariantCulture);
1411                                 }
1412                                 catch (FormatException) {
1413                                         Report.Warning (1692, 1, Location, "Invalid number");
1414                                 }
1415                         }
1416                         return values;
1417                 }
1418
1419                 bool eval_val (string s)
1420                 {
1421                         if (s == "true")
1422                                 return true;
1423                         if (s == "false")
1424                                 return false;
1425
1426                         if (defines == null)
1427                                 return false;
1428                         if (defines.Contains (s))
1429                                 return true;
1430
1431                         return false;
1432                 }
1433
1434                 bool pp_primary (ref string s)
1435                 {
1436                         s = s.Trim ();
1437                         int len = s.Length;
1438
1439                         if (len > 0){
1440                                 char c = s [0];
1441
1442                                 if (c == '('){
1443                                         s = s.Substring (1);
1444                                         bool val = pp_expr (ref s);
1445                                         if (s.Length > 0 && s [0] == ')'){
1446                                                 s = s.Substring (1);
1447                                                 return val;
1448                                         }
1449                                         Error_InvalidDirective ();
1450                                         return false;
1451                                 }
1452
1453                                 if (is_identifier_start_character (c)){
1454                                         int j = 1;
1455
1456                                         while (j < len){
1457                                                 c = s [j];
1458
1459                                                 if (is_identifier_part_character (c)){
1460                                                         j++;
1461                                                         continue;
1462                                                 }
1463                                                 bool v = eval_val (s.Substring (0, j));
1464                                                 s = s.Substring (j);
1465                                                 return v;
1466                                         }
1467                                         bool vv = eval_val (s);
1468                                         s = "";
1469                                         return vv;
1470                                 }
1471                         }
1472                         Error_InvalidDirective ();
1473                         return false;
1474                 }
1475
1476                 bool pp_unary (ref string s)
1477                 {
1478                         s = s.Trim ();
1479                         int len = s.Length;
1480
1481                         if (len > 0){
1482                                 if (s [0] == '!'){
1483                                         if (len > 1 && s [1] == '='){
1484                                                 Error_InvalidDirective ();
1485                                                 return false;
1486                                         }
1487                                         s = s.Substring (1);
1488                                         return ! pp_primary (ref s);
1489                                 } else
1490                                         return pp_primary (ref s);
1491                         } else {
1492                                 Error_InvalidDirective ();
1493                                 return false;
1494                         }
1495                 }
1496
1497                 bool pp_eq (ref string s)
1498                 {
1499                         bool va = pp_unary (ref s);
1500
1501                         s = s.Trim ();
1502                         int len = s.Length;
1503                         if (len > 0){
1504                                 if (s [0] == '='){
1505                                         if (len > 2 && s [1] == '='){
1506                                                 s = s.Substring (2);
1507                                                 return va == pp_unary (ref s);
1508                                         } else {
1509                                                 Error_InvalidDirective ();
1510                                                 return false;
1511                                         }
1512                                 } else if (s [0] == '!' && len > 1 && s [1] == '='){
1513                                         s = s.Substring (2);
1514
1515                                         return va != pp_unary (ref s);
1516
1517                                 }
1518                         }
1519
1520                         return va;
1521
1522                 }
1523
1524                 bool pp_and (ref string s)
1525                 {
1526                         bool va = pp_eq (ref s);
1527
1528                         s = s.Trim ();
1529                         int len = s.Length;
1530                         if (len > 0){
1531                                 if (s [0] == '&'){
1532                                         if (len > 2 && s [1] == '&'){
1533                                                 s = s.Substring (2);
1534                                                 return (va & pp_and (ref s));
1535                                         } else {
1536                                                 Error_InvalidDirective ();
1537                                                 return false;
1538                                         }
1539                                 }
1540                         }
1541                         return va;
1542                 }
1543
1544                 //
1545                 // Evaluates an expression for `#if' or `#elif'
1546                 //
1547                 bool pp_expr (ref string s)
1548                 {
1549                         bool va = pp_and (ref s);
1550                         s = s.Trim ();
1551                         int len = s.Length;
1552                         if (len > 0){
1553                                 char c = s [0];
1554
1555                                 if (c == '|'){
1556                                         if (len > 2 && s [1] == '|'){
1557                                                 s = s.Substring (2);
1558                                                 return va | pp_expr (ref s);
1559                                         } else {
1560                                                 Error_InvalidDirective ();
1561                                                 return false;
1562                                         }
1563                                 }
1564                         }
1565
1566                         return va;
1567                 }
1568
1569                 bool eval (string s)
1570                 {
1571                         bool v = pp_expr (ref s);
1572                         s = s.Trim ();
1573                         if (s.Length != 0){
1574                                 return false;
1575                         }
1576
1577                         return v;
1578                 }
1579
1580                 void Error_InvalidDirective ()
1581                 {
1582                         Report.Error (1517, Location, "Invalid preprocessor directive");
1583                 }
1584
1585                 void Error_UnexpectedDirective (string extra)
1586                 {
1587                         Report.Error (
1588                                 1028, Location,
1589                                 "Unexpected processor directive (" + extra + ")");
1590                 }
1591
1592                 void Error_TokensSeen ()
1593                 {
1594                         Report.Error (1032, Location,
1595                                 "Cannot define or undefine preprocessor symbols after first token in file");
1596                 }
1597
1598                 //
1599                 // Set to false to stop handling preprocesser directives
1600                 //
1601                 bool process_directives = true;
1602
1603                 //
1604                 // if true, then the code continues processing the code
1605                 // if false, the code stays in a loop until another directive is
1606                 // reached.
1607                 //
1608                 bool handle_preprocessing_directive (bool caller_is_taking)
1609                 {
1610                         string cmd, arg;
1611                         bool region_directive = false;
1612
1613                         get_cmd_arg (out cmd, out arg);
1614
1615                         // Eat any trailing whitespaces and single-line comments
1616                         if (arg.IndexOf ("//") != -1)
1617                                 arg = arg.Substring (0, arg.IndexOf ("//"));
1618                         arg = arg.TrimEnd (' ', '\t');
1619
1620                         //
1621                         // The first group of pre-processing instructions is always processed
1622                         //
1623                         switch (cmd){
1624                         case "pragma":
1625                                 if (RootContext.Version == LanguageVersion.ISO_1) {
1626                                         Report.FeatureIsNotStandardized (Location, "#pragma");
1627                                         return caller_is_taking;
1628                                 }
1629
1630                                 PreProcessPragma (arg);
1631                                 return caller_is_taking;
1632
1633                         case "line":
1634                                 if (!PreProcessLine (arg))
1635                                         Report.Error (
1636                                                 1576, Location,
1637                                                 "The line number specified for #line directive is missing or invalid");
1638                                 return caller_is_taking;
1639
1640                         case "region":
1641                                 region_directive = true;
1642                                 arg = "true";
1643                                 goto case "if";
1644
1645                         case "endregion":
1646                                 region_directive = true;
1647                                 goto case "endif";
1648
1649                         case "if":
1650                                 if (arg.Length == 0){
1651                                         Error_InvalidDirective ();
1652                                         return true;
1653                                 }
1654                                 bool taking = false;
1655                                 if (ifstack == null)
1656                                         ifstack = new Stack (2);
1657
1658                                 if (ifstack.Count == 0){
1659                                         taking = true;
1660                                 } else {
1661                                         int state = (int) ifstack.Peek ();
1662                                         if ((state & TAKING) != 0)
1663                                                 taking = true;
1664                                 }
1665
1666                                 if (eval (arg) && taking){
1667                                         int push = TAKING | TAKEN_BEFORE | PARENT_TAKING;
1668                                         if (region_directive)
1669                                                 push |= REGION;
1670                                         ifstack.Push (push);
1671                                         return true;
1672                                 } else {
1673                                         int push = (taking ? PARENT_TAKING : 0);
1674                                         if (region_directive)
1675                                                 push |= REGION;
1676                                         ifstack.Push (push);
1677                                         return false;
1678                                 }
1679
1680                         case "endif":
1681                                 if (ifstack == null || ifstack.Count == 0){
1682                                         Error_UnexpectedDirective ("no #if for this #endif");
1683                                         return true;
1684                                 } else {
1685                                         int pop = (int) ifstack.Pop ();
1686
1687                                         if (region_directive && ((pop & REGION) == 0))
1688                                                 Report.Error (1027, Location, "Expected `#endif' directive");
1689                                         else if (!region_directive && ((pop & REGION) != 0))
1690                                                 Report.Error (1038, Location, "#endregion directive expected");
1691
1692                                         if (!region_directive && arg.Length != 0) {
1693                                                 Report.Error (1025, Location, "Single-line comment or end-of-line expected");
1694                                         }
1695
1696                                         if (ifstack.Count == 0)
1697                                                 return true;
1698                                         else {
1699                                                 int state = (int) ifstack.Peek ();
1700
1701                                                 if ((state & TAKING) != 0)
1702                                                         return true;
1703                                                 else
1704                                                         return false;
1705                                         }
1706                                 }
1707
1708                         case "elif":
1709                                 if (ifstack == null || ifstack.Count == 0){
1710                                         Error_UnexpectedDirective ("no #if for this #elif");
1711                                         return true;
1712                                 } else {
1713                                         int state = (int) ifstack.Peek ();
1714
1715                                         if ((state & REGION) != 0) {
1716                                                 Report.Error (1038, Location, "#endregion directive expected");
1717                                                 return true;
1718                                         }
1719
1720                                         if ((state & ELSE_SEEN) != 0){
1721                                                 Error_UnexpectedDirective ("#elif not valid after #else");
1722                                                 return true;
1723                                         }
1724
1725                                         if ((state & (TAKEN_BEFORE | TAKING)) != 0)
1726                                                 return false;
1727
1728                                         if (eval (arg) && ((state & PARENT_TAKING) != 0)){
1729                                                 state = (int) ifstack.Pop ();
1730                                                 ifstack.Push (state | TAKING | TAKEN_BEFORE);
1731                                                 return true;
1732                                         } else
1733                                                 return false;
1734                                 }
1735
1736                         case "else":
1737                                 if (ifstack == null || ifstack.Count == 0){
1738                                         Error_UnexpectedDirective ("no #if for this #else");
1739                                         return true;
1740                                 } else {
1741                                         int state = (int) ifstack.Peek ();
1742
1743                                         if ((state & REGION) != 0) {
1744                                                 Report.Error (1038, Location, "#endregion directive expected");
1745                                                 return true;
1746                                         }
1747
1748                                         if ((state & ELSE_SEEN) != 0){
1749                                                 Error_UnexpectedDirective ("#else within #else");
1750                                                 return true;
1751                                         }
1752
1753                                         ifstack.Pop ();
1754
1755                                         bool ret;
1756                                         if ((state & TAKEN_BEFORE) == 0){
1757                                                 ret = ((state & PARENT_TAKING) != 0);
1758                                         } else
1759                                                 ret = false;
1760
1761                                         if (ret)
1762                                                 state |= TAKING;
1763                                         else
1764                                                 state &= ~TAKING;
1765
1766                                         ifstack.Push (state | ELSE_SEEN);
1767
1768                                         return ret;
1769                                 }
1770                         }
1771
1772                         //
1773                         // These are only processed if we are in a `taking' block
1774                         //
1775                         if (!caller_is_taking)
1776                                 return false;
1777
1778                         switch (cmd){
1779                         case "define":
1780                                 if (any_token_seen){
1781                                         Error_TokensSeen ();
1782                                         return true;
1783                                 }
1784                                 PreProcessDefinition (true, arg);
1785                                 return true;
1786
1787                         case "undef":
1788                                 if (any_token_seen){
1789                                         Error_TokensSeen ();
1790                                         return true;
1791                                 }
1792                                 PreProcessDefinition (false, arg);
1793                                 return true;
1794
1795                         case "error":
1796                                 Report.Error (1029, Location, "#error: '" + arg + "'");
1797                                 return true;
1798
1799                         case "warning":
1800                                 Report.Warning (1030, 1, Location, "#warning: `{0}'", arg);
1801                                 return true;
1802                         }
1803
1804                         Report.Error (1024, Location, "Wrong preprocessor directive");
1805                         return true;
1806
1807                 }
1808
1809                 private int consume_string (bool quoted)
1810                 {
1811                         int c;
1812                         string_builder.Length = 0;
1813
1814                         while ((c = getChar ()) != -1){
1815                                 if (c == '"'){
1816                                         if (quoted && peekChar () == '"'){
1817                                                 string_builder.Append ((char) c);
1818                                                 getChar ();
1819                                                 continue;
1820                                         } else {
1821                                                 val = string_builder.ToString ();
1822                                                 return Token.LITERAL_STRING;
1823                                         }
1824                                 }
1825
1826                                 if (c == '\n'){
1827                                         if (!quoted)
1828                                                 Report.Error (1010, Location, "Newline in constant");
1829                                 }
1830
1831                                 if (!quoted){
1832                                         c = escape (c);
1833                                         if (c == -1)
1834                                                 return Token.ERROR;
1835                                 }
1836                                 string_builder.Append ((char) c);
1837                         }
1838
1839                         Report.Error (1039, Location, "Unterminated string literal");
1840                         return Token.EOF;
1841                 }
1842
1843                 private int consume_identifier (int s)
1844                 {
1845                         int res = consume_identifier (s, false);
1846
1847                         if (doc_state == XmlCommentState.Allowed)
1848                                 doc_state = XmlCommentState.NotAllowed;
1849                         switch (res) {
1850                         case Token.USING:
1851                         case Token.NAMESPACE:
1852                                 check_incorrect_doc_comment ();
1853                                 break;
1854                         }
1855
1856                         if (res == Token.PARTIAL) {
1857                                 // Save current position and parse next token.
1858                                 int old = reader.Position;
1859                                 int old_putback = putback_char;
1860                                 int old_ref_line = ref_line;
1861                                 int old_col = col;
1862
1863                                 putback_char = -1;
1864
1865                                 int next_token = token ();
1866                                 bool ok = (next_token == Token.CLASS) ||
1867                                         (next_token == Token.STRUCT) ||
1868                                         (next_token == Token.INTERFACE) ||
1869                                         (next_token == Token.ENUM); // "partial" is a keyword in 'partial enum', even though it's not valid
1870
1871                                 reader.Position = old;
1872                                 ref_line = old_ref_line;
1873                                 col = old_col;
1874                                 putback_char = old_putback;
1875
1876                                 if (ok)
1877                                         return res;
1878                                 else {
1879                                         val = new LocatedToken (Location, "partial");
1880                                         return Token.IDENTIFIER;
1881                                 }
1882                         }
1883
1884                         return res;
1885                 }
1886
1887                 private int consume_identifier (int s, bool quoted)
1888                 {
1889                         int pos = 1;
1890                         int c = -1;
1891
1892                         id_builder [0] = (char) s;
1893
1894                         current_location = new Location (ref_line, Col);
1895
1896                         while ((c = getChar ()) != -1) {
1897                         loop:
1898                                 if (is_identifier_part_character ((char) c)){
1899                                         if (pos == max_id_size){
1900                                                 Report.Error (645, Location, "Identifier too long (limit is 512 chars)");
1901                                                 return Token.ERROR;
1902                                         }
1903
1904                                         id_builder [pos++] = (char) c;
1905 //                                      putback_char = -1;
1906                                 } else if (c == '\\') {
1907                                         c = escape (c);
1908                                         goto loop;
1909                                 } else {
1910 //                                      putback_char = c;
1911                                         putback (c);
1912                                         break;
1913                                 }
1914                         }
1915
1916                         //
1917                         // Optimization: avoids doing the keyword lookup
1918                         // on uppercase letters and _
1919                         //
1920                         if (!quoted && (s >= 'a' || s == '_')){
1921                                 int keyword = GetKeyword (id_builder, pos);
1922                                 if (keyword != -1) {
1923                                         val = Location;
1924                                         return keyword;
1925                                 }
1926                         }
1927
1928                         //
1929                         // Keep identifiers in an array of hashtables to avoid needless
1930                         // allocations
1931                         //
1932
1933                         if (identifiers [pos] != null) {
1934                                 val = identifiers [pos][id_builder];
1935                                 if (val != null) {
1936                                         val = new LocatedToken (Location, (string) val);
1937                                         if (quoted)
1938                                                 escapedIdentifiers.Add (val);
1939                                         return Token.IDENTIFIER;
1940                                 }
1941                         }
1942                         else
1943                                 identifiers [pos] = new CharArrayHashtable (pos);
1944
1945                         val = new String (id_builder, 0, pos);
1946                         if (RootContext.Version == LanguageVersion.ISO_1) {
1947                                 for (int i = 1; i < id_builder.Length; i += 3) {
1948                                         if (id_builder [i] == '_' && (id_builder [i - 1] == '_' || id_builder [i + 1] == '_')) {
1949                                                 Report.Error (1638, Location,
1950                                                         "`{0}': Any identifier with double underscores cannot be used when ISO language version mode is specified", val.ToString ());
1951                                                 break;
1952                                         }
1953                                 }
1954                         }
1955
1956                         char [] chars = new char [pos];
1957                         Array.Copy (id_builder, chars, pos);
1958
1959                         identifiers [pos] [chars] = val;
1960
1961                         val = new LocatedToken (Location, (string) val);
1962                         if (quoted)
1963                                 escapedIdentifiers.Add (val);
1964                         return Token.IDENTIFIER;
1965                 }
1966
1967                 public int xtoken ()
1968                 {
1969                         int t;
1970                         bool doread = false;
1971                         int c;
1972
1973                         // Whether we have seen comments on the current line
1974                         bool comments_seen = false;
1975
1976                         val = null;
1977                         // optimization: eliminate col and implement #directive semantic correctly.
1978                         for (;(c = getChar ()) != -1;) {
1979                                 if (c == ' ')
1980                                         continue;
1981
1982                                 if (c == '\t') {
1983                                         continue;
1984                                 }
1985
1986                                 if (c == ' ' || c == '\f' || c == '\v' || c == 0xa0)
1987                                         continue;
1988
1989                                 if (c == '\r') {
1990                                         if (peekChar () == '\n')
1991                                                 getChar ();
1992
1993                                         any_token_seen |= tokens_seen;
1994                                         tokens_seen = false;
1995                                         comments_seen = false;
1996                                         continue;
1997                                 }
1998
1999                                 // Handle double-slash comments.
2000                                 if (c == '/'){
2001                                         int d = peekChar ();
2002
2003                                         if (d == '/'){
2004                                                 getChar ();
2005                                                 if (RootContext.Documentation != null && peekChar () == '/') {
2006                                                         getChar ();
2007                                                         // Don't allow ////.
2008                                                         if ((d = peekChar ()) != '/') {
2009                                                                 update_comment_location ();
2010                                                                 if (doc_state == XmlCommentState.Allowed)
2011                                                                         handle_one_line_xml_comment ();
2012                                                                 else if (doc_state == XmlCommentState.NotAllowed)
2013                                                                         warn_incorrect_doc_comment ();
2014                                                         }
2015                                                 }
2016                                                 while ((d = getChar ()) != -1 && (d != '\n') && d != '\r')
2017                                                 if (d == '\n'){
2018                                                 }
2019                                                 any_token_seen |= tokens_seen;
2020                                                 tokens_seen = false;
2021                                                 comments_seen = false;
2022                                                 continue;
2023                                         } else if (d == '*'){
2024                                                 getChar ();
2025                                                 bool docAppend = false;
2026                                                 if (RootContext.Documentation != null && peekChar () == '*') {
2027                                                         getChar ();
2028                                                         update_comment_location ();
2029                                                         // But when it is /**/, just do nothing.
2030                                                         if (peekChar () == '/') {
2031                                                                 getChar ();
2032                                                                 continue;
2033                                                         }
2034                                                         if (doc_state == XmlCommentState.Allowed)
2035                                                                 docAppend = true;
2036                                                         else if (doc_state == XmlCommentState.NotAllowed)
2037                                                                 warn_incorrect_doc_comment ();
2038                                                 }
2039
2040                                                 int current_comment_start = 0;
2041                                                 if (docAppend) {
2042                                                         current_comment_start = xml_comment_buffer.Length;
2043                                                         xml_comment_buffer.Append (Environment.NewLine);
2044                                                 }
2045
2046                                                 Location start_location = Location;
2047
2048                                                 while ((d = getChar ()) != -1){
2049                                                         if (d == '*' && peekChar () == '/'){
2050                                                                 getChar ();
2051                                                                 comments_seen = true;
2052                                                                 break;
2053                                                         }
2054                                                         if (docAppend)
2055                                                                 xml_comment_buffer.Append ((char) d);
2056
2057                                                         if (d == '\n'){
2058                                                                 any_token_seen |= tokens_seen;
2059                                                                 tokens_seen = false;
2060                                                                 //
2061                                                                 // Reset 'comments_seen' just to be consistent.
2062                                                                 // It doesn't matter either way, here.
2063                                                                 //
2064                                                                 comments_seen = false;
2065                                                         }
2066                                                 }
2067                                                 if (!comments_seen)
2068                                                         Report.Error (1035, start_location, "End-of-file found, '*/' expected");
2069
2070                                                 if (docAppend)
2071                                                         update_formatted_doc_comment (current_comment_start);
2072                                                 continue;
2073                                         }
2074                                         goto is_punct_label;
2075                                 }
2076
2077
2078                                 if (c == '\\' || is_identifier_start_character ((char)c)){
2079                                         tokens_seen = true;
2080                                         return consume_identifier (c);
2081                                 }
2082
2083                         is_punct_label:
2084                                 current_location = new Location (ref_line, Col);
2085                                 if ((t = is_punct ((char)c, ref doread)) != Token.ERROR){
2086                                         tokens_seen = true;
2087                                         if (doread){
2088                                                 getChar ();
2089                                         }
2090                                         return t;
2091                                 }
2092
2093                                 // white space
2094                                 if (c == '\n'){
2095                                         any_token_seen |= tokens_seen;
2096                                         tokens_seen = false;
2097                                         comments_seen = false;
2098                                         continue;
2099                                 }
2100
2101                                 if (c >= '0' && c <= '9'){
2102                                         tokens_seen = true;
2103                                         return is_number (c);
2104                                 }
2105
2106                                 if (c == '.'){
2107                                         tokens_seen = true;
2108                                         int peek = peekChar ();
2109                                         if (peek >= '0' && peek <= '9')
2110                                                 return is_number (c);
2111                                         return Token.DOT;
2112                                 }
2113
2114                                 /* For now, ignore pre-processor commands */
2115                                 // FIXME: In C# the '#' is not limited to appear
2116                                 // on the first column.
2117                                 if (c == '#') {
2118                                         // return NONE if we're not processing directives (during token peeks)
2119                                         if (!process_directives)
2120                                                 return Token.NONE;
2121
2122                                         bool cont = true;
2123                                         if (tokens_seen || comments_seen) {
2124                                                error_details = "Preprocessor directives must appear as the first" +
2125                                                " non-whitespace character on a line.";
2126
2127                                                Report.Error (1040, Location, error_details);
2128
2129                                                return Token.ERROR;
2130                                        }
2131
2132                                 start_again:
2133
2134                                         cont = handle_preprocessing_directive (cont);
2135
2136                                         if (cont){
2137                                                 continue;
2138                                         }
2139
2140                                         bool skipping = false;
2141                                         for (;(c = getChar ()) != -1;){
2142                                                 if (c == '\n'){
2143                                                         skipping = false;
2144                                                 } else if (c == ' ' || c == '\t' || c == '\v' || c == '\r' || c == 0xa0)
2145                                                         continue;
2146                                                 else if (c != '#')
2147                                                         skipping = true;
2148                                                 if (c == '#' && !skipping)
2149                                                         goto start_again;
2150                                         }
2151                                         any_token_seen |= tokens_seen;
2152                                         tokens_seen = false;
2153                                         if (c == -1)
2154                                                 Report.Error (1027, Location, "Expected `#endif' directive");
2155                                         continue;
2156                                 }
2157
2158                                 if (c == '"')
2159                                         return consume_string (false);
2160
2161                                 if (c == '\''){
2162                                         c = getChar ();
2163                                         tokens_seen = true;
2164                                         if (c == '\''){
2165                                                 error_details = "Empty character literal";
2166                                                 Report.Error (1011, Location, error_details);
2167                                                 return Token.ERROR;
2168                                         }
2169                                         if (c == '\r' || c == '\n') {
2170                                                 Report.Error (1010, Location, "Newline in constant");
2171                                                 return Token.ERROR;
2172                                         }
2173                                         c = escape (c);
2174                                         if (c == -1)
2175                                                 return Token.ERROR;
2176                                         val = new System.Char ();
2177                                         val = (char) c;
2178                                         c = getChar ();
2179
2180                                         if (c != '\''){
2181                                                 error_details = "Too many characters in character literal";
2182                                                 Report.Error (1012, Location, error_details);
2183
2184                                                 // Try to recover, read until newline or next "'"
2185                                                 while ((c = getChar ()) != -1){
2186                                                         if (c == '\n'){
2187                                                                 break;
2188                                                         }
2189                                                         else if (c == '\'')
2190                                                                 break;
2191                                                 }
2192                                                 return Token.ERROR;
2193                                         }
2194                                         return Token.LITERAL_CHARACTER;
2195                                 }
2196
2197                                 if (c == '@') {
2198                                         c = getChar ();
2199                                         if (c == '"') {
2200                                                 tokens_seen = true;
2201                                                 return consume_string (true);
2202                                         } else if (is_identifier_start_character ((char) c)){
2203                                                 return consume_identifier (c, true);
2204                                         } else {
2205                                                 Report.Error (1646, Location, "Keyword, identifier, or string expected after verbatim specifier: @");
2206                                         }
2207                                 }
2208
2209                                 error_details = ((char)c).ToString ();
2210
2211                                 return Token.ERROR;
2212                         }
2213
2214                         return Token.EOF;
2215                 }
2216
2217                 //
2218                 // Handles one line xml comment
2219                 //
2220                 private void handle_one_line_xml_comment ()
2221                 {
2222                         int c;
2223                         while ((c = peekChar ()) == ' ')
2224                                 getChar (); // skip heading whitespaces.
2225                         while ((c = peekChar ()) != -1 && c != '\n' && c != '\r') {
2226                                 xml_comment_buffer.Append ((char) getChar ());
2227                         }
2228                         if (c == '\r' || c == '\n')
2229                                 xml_comment_buffer.Append (Environment.NewLine);
2230                 }
2231
2232                 //
2233                 // Remove heading "*" in Javadoc-like xml documentation.
2234                 //
2235                 private void update_formatted_doc_comment (int current_comment_start)
2236                 {
2237                         int length = xml_comment_buffer.Length - current_comment_start;
2238                         string [] lines = xml_comment_buffer.ToString (
2239                                 current_comment_start,
2240                                 length).Replace ("\r", "").Split ('\n');
2241
2242                         // The first line starts with /**, thus it is not target
2243                         // for the format check.
2244                         for (int i = 1; i < lines.Length; i++) {
2245                                 string s = lines [i];
2246                                 int idx = s.IndexOf ('*');
2247                                 string head = null;
2248                                 if (idx < 0) {
2249                                         if (i < lines.Length - 1)
2250                                                 return;
2251                                         head = s;
2252                                 } else
2253                                         head = s.Substring (0, idx);
2254                                 foreach (char c in head)
2255                                         if (c != ' ')
2256                                                 return;
2257                                 lines [i] = s.Substring (idx + 1);
2258                         }
2259                         xml_comment_buffer.Remove (current_comment_start, length);
2260                         xml_comment_buffer.Insert (current_comment_start, String.Join (Environment.NewLine, lines));
2261                 }
2262
2263                 //
2264                 // Updates current comment location.
2265                 //
2266                 private void update_comment_location ()
2267                 {
2268                         if (current_comment_location.IsNull) {
2269                                 // "-2" is for heading "//" or "/*"
2270                                 current_comment_location =
2271                                         new Location (ref_line, col - 2);
2272                         }
2273                 }
2274
2275                 //
2276                 // Checks if there was incorrect doc comments and raise
2277                 // warnings.
2278                 //
2279                 public void check_incorrect_doc_comment ()
2280                 {
2281                         if (xml_comment_buffer.Length > 0)
2282                                 warn_incorrect_doc_comment ();
2283                 }
2284
2285                 //
2286                 // Raises a warning when tokenizer found incorrect doccomment
2287                 // markup.
2288                 //
2289                 private void warn_incorrect_doc_comment ()
2290                 {
2291                         if (doc_state != XmlCommentState.Error) {
2292                                 doc_state = XmlCommentState.Error;
2293                                 // in csc, it is 'XML comment is not placed on
2294                                 // a valid language element'. But that does not
2295                                 // make sense.
2296                                 Report.Warning (1587, 2, Location, "XML comment is not placed on a valid language element");
2297                         }
2298                 }
2299
2300                 //
2301                 // Consumes the saved xml comment lines (if any)
2302                 // as for current target member or type.
2303                 //
2304                 public string consume_doc_comment ()
2305                 {
2306                         if (xml_comment_buffer.Length > 0) {
2307                                 string ret = xml_comment_buffer.ToString ();
2308                                 reset_doc_comment ();
2309                                 return ret;
2310                         }
2311                         return null;
2312                 }
2313
2314                 void reset_doc_comment ()
2315                 {
2316                         xml_comment_buffer.Length = 0;
2317                         current_comment_location = Location.Null;
2318                 }
2319
2320                 public void cleanup ()
2321                 {
2322                         if (ifstack != null && ifstack.Count >= 1) {
2323                                 int state = (int) ifstack.Pop ();
2324                                 if ((state & REGION) != 0)
2325                                         Report.Error (1038, Location, "#endregion directive expected");
2326 //                              else
2327 //                                      Report.Error (1027, Location, "Expected `#endif' directive");
2328                         }
2329                 }
2330         }
2331
2332         //
2333         // Indicates whether it accepts XML documentation or not.
2334         //
2335         public enum XmlCommentState {
2336                 // comment is allowed in this state.
2337                 Allowed,
2338                 // comment is not allowed in this state.
2339                 NotAllowed,
2340                 // once comments appeared when it is NotAllowed, then the
2341                 // state is changed to it, until the state is changed to
2342                 // .Allowed.
2343                 Error
2344         }
2345 }