mcs/mcs/constant.cs

   1 //
   2 // constant.cs: Constants.
   3 //
   4 // Author:
   5 //   Miguel de Icaza (miguel@ximian.com)
   6 //   Marek Safar (marek.safar@seznam.cz)
   7 //
   8 // (C) 2001 Ximian, Inc.
   9 //
  10 //
  11
  12 namespace Mono.CSharp {
  13
  14         using System;
  15         using System.Reflection.Emit;
  16
  17         /// <summary>
  18         ///   Base class for constants and literals.
  19         /// </summary>
  20         public abstract class Constant : Expression {
  21
  22                 protected Constant (Location loc)
  23                 {
  24                         this.loc = loc;
  25                 }
  26
  27                 /// <remarks>
  28                 ///   This is different from ToString in that ToString
  29                 ///   is supposed to be there for debugging purposes,
  30                 ///   and is not guaranteed to be useful for anything else,
  31                 ///   AsString() will provide something that can be used
  32                 ///   for round-tripping C# code.  Maybe it can be used
  33                 ///   for IL assembly as well.
  34                 /// </remarks>
  35                 public abstract string AsString ();
  36
  37                 override public string ToString ()
  38                 {
  39                         return this.GetType ().Name + " (" + AsString () + ")";
  40                 }
  41
  42                 public override bool GetAttributableValue (out object value)
  43                 {
  44                         value = GetTypedValue ();
  45                         return true;
  46                 }
  47
  48                 /// <summary>
  49                 ///  This is used to obtain the actual value of the literal
  50                 ///  cast into an object.
  51                 /// </summary>
  52                 public abstract object GetValue ();
  53
  54                 public virtual object GetTypedValue ()
  55                 {
  56                         return GetValue ();
  57                 }
  58
  59                 /// <summary>
  60                 ///   Constants are always born in a fully resolved state
  61                 /// </summary>
  62                 public override Expression DoResolve (EmitContext ec)
  63                 {
  64                         return this;
  65                 }
  66
  67                 //
  68                 // The various ToXXXX conversion functions are used by the constant
  69                 // folding evaluator.   A null value is returned if the conversion is
  70                 // not possible.
  71                 //
  72                 // Note: not all the patterns for catching `implicit_conv' are the same.
  73                 // some implicit conversions can never be performed between two types
  74                 // even if the conversion would be lossless (for example short to uint),
  75                 // but some conversions are explicitly permitted by the standard provided
  76                 // that there will be no loss of information (for example, int to uint).
  77                 //
  78                 public DoubleConstant ToDouble (Location loc)
  79                 {
  80                         DoubleConstant c = ConvertToDouble ();
  81
  82                         if (c == null)
  83                                 Error_ValueCannotBeConverted (loc, TypeManager.double_type, false);
  84
  85                         return c;
  86                 }
  87
  88                 public FloatConstant ToFloat (Location loc)
  89                 {
  90                         FloatConstant c = ConvertToFloat ();
  91
  92                         if (c == null)
  93                                 Error_ValueCannotBeConverted (loc, TypeManager.float_type, false);
  94
  95                         return c;
  96                 }
  97
  98                 public ULongConstant ToULong (Location loc)
  99                 {
 100                         ULongConstant c = ConvertToULong ();
 101
 102                         if (c == null)
 103                                 Error_ValueCannotBeConverted (loc, TypeManager.uint64_type, false);
 104
 105                         return c;
 106                 }
 107
 108                 public LongConstant ToLong (Location loc)
 109                 {
 110                         LongConstant c = ConvertToLong ();
 111
 112                         if (c == null)
 113                                 Error_ValueCannotBeConverted (loc, TypeManager.int64_type, false);
 114
 115                         return c;
 116                 }
 117
 118                 public UIntConstant ToUInt (Location loc)
 119                 {
 120                         UIntConstant c = ConvertToUInt ();
 121
 122                         if (c == null)
 123                                 Error_ValueCannotBeConverted (loc, TypeManager.uint32_type, false);
 124
 125                         return c;
 126                 }
 127
 128                 public IntConstant ToInt (Location loc)
 129                 {
 130                         IntConstant c = ConvertToInt ();
 131
 132                         if (c == null)
 133                                 Error_ValueCannotBeConverted (loc, TypeManager.int32_type, false);
 134
 135                         return c;
 136                 }
 137
 138                 public DecimalConstant ToDecimal (Location loc)
 139                 {
 140                         DecimalConstant c = ConvertToDecimal ();
 141
 142                         if (c == null)
 143                                 Error_ValueCannotBeConverted (loc, TypeManager.decimal_type, false);
 144
 145                         return c;
 146                 }
 147
 148                 public virtual Constant ToType (Type type, Location loc)
 149                 {
 150                         if (Type == type)
 151                                 return this;
 152
 153                         if (type == TypeManager.object_type)
 154                                 return this;
 155
 156                         if (!Convert.ImplicitStandardConversionExists (this, type)){
 157                                 Error_ValueCannotBeConverted (loc, type, false);
 158                                 return null;
 159                         }
 160
 161                         // Special-case: The 0 literal can be converted to an enum value,
 162                         // and ImplicitStandardConversionExists will return true in that case.
 163                         if (IsZeroInteger && Type == TypeManager.int32_type && TypeManager.IsEnumType (type)) {
 164                                 return new EnumConstant (this, type);
 165                         }
 166
 167                         bool fail;
 168                         object constant_value = TypeManager.ChangeType (GetValue (), type, out fail);
 169                         if (fail){
 170                                 Error_ValueCannotBeConverted (loc, type, false);
 171
 172                                 //
 173                                 // We should always catch the error before this is ever
 174                                 // reached, by calling Convert.ImplicitStandardConversionExists
 175                                 //
 176                                 throw new Exception (
 177                                         String.Format ("LookupConstantValue: This should never be reached {0} {1}", Type, type));
 178                         }
 179
 180                         Constant retval;
 181                         if (type == TypeManager.int32_type)
 182                                 retval = new IntConstant ((int) constant_value, loc);
 183                         else if (type == TypeManager.uint32_type)
 184                                 retval = new UIntConstant ((uint) constant_value, loc);
 185                         else if (type == TypeManager.int64_type)
 186                                 retval = new LongConstant ((long) constant_value, loc);
 187                         else if (type == TypeManager.uint64_type)
 188                                 retval = new ULongConstant ((ulong) constant_value, loc);
 189                         else if (type == TypeManager.float_type)
 190                                 retval = new FloatConstant ((float) constant_value, loc);
 191                         else if (type == TypeManager.double_type)
 192                                 retval = new DoubleConstant ((double) constant_value, loc);
 193                         else if (type == TypeManager.string_type)
 194                                 retval = new StringConstant ((string) constant_value, loc);
 195                         else if (type == TypeManager.short_type)
 196                                 retval = new ShortConstant ((short) constant_value, loc);
 197                         else if (type == TypeManager.ushort_type)
 198                                 retval = new UShortConstant ((ushort) constant_value, loc);
 199                         else if (type == TypeManager.sbyte_type)
 200                                 retval = new SByteConstant ((sbyte) constant_value, loc);
 201                         else if (type == TypeManager.byte_type)
 202                                 retval = new ByteConstant ((byte) constant_value, loc);
 203                         else if (type == TypeManager.char_type)
 204                                 retval = new CharConstant ((char) constant_value, loc);
 205                         else if (type == TypeManager.bool_type)
 206                                 retval = new BoolConstant ((bool) constant_value, loc);
 207                         else if (type == TypeManager.decimal_type)
 208                                 retval = new DecimalConstant ((decimal) constant_value, loc);
 209                         else
 210                                 throw new Exception ("LookupConstantValue: Unhandled constant type: " + type);
 211
 212                         return retval;
 213                 }
 214
 215                 protected static void CheckRange (EmitContext ec, ulong value, ulong max)
 216                 {
 217                         if (!ec.ConstantCheckState)
 218                                 return;
 219
 220                         if (value > max)
 221                                 throw new OverflowException ();
 222                 }
 223
 224                 protected static void CheckRange (EmitContext ec, double value, long min, long max)
 225                 {
 226                         if (!ec.ConstantCheckState)
 227                                 return;
 228
 229                         if (((value < min) || (value > max)))
 230                                 throw new OverflowException ();
 231                 }
 232
 233                 protected static void CheckUnsigned (EmitContext ec, long value)
 234                 {
 235                         if (!ec.ConstantCheckState)
 236                                 return;
 237
 238                         if (value < 0)
 239                                 throw new OverflowException ();
 240                 }
 241
 242                 /// <summary>
 243                 /// Maybe ConvertTo name is better. It tries to convert `this' constant to target_type.
 244                 /// It throws OverflowException
 245                 /// </summary>
 246                 public abstract Constant Reduce (EmitContext ec, Type target_type);
 247
 248                 /// <summary>
 249                 ///   Attempts to do a compile-time folding of a constant cast.
 250                 /// </summary>
 251                 public Constant TryReduce (EmitContext ec, Type target_type, Location loc)
 252                 {
 253                         try {
 254                                 return  TryReduce (ec, target_type);
 255                         }
 256                         catch (OverflowException) {
 257                                 Report.Error (221, loc, "Constant value `{0}' cannot be converted to a `{1}' (use `unchecked' syntax to override)",
 258                                         GetValue ().ToString (), TypeManager.CSharpName (target_type));
 259                                 throw;
 260                         }
 261                 }
 262
 263                 Constant TryReduce (EmitContext ec, Type target_type)
 264                 {
 265                         if (Type == target_type)
 266                                 return this;
 267
 268                         if (TypeManager.IsEnumType (target_type)) {
 269                                 Constant c = TryReduce (ec, TypeManager.EnumToUnderlying (target_type));
 270                                 if (c == null)
 271                                         return null;
 272
 273                                 return new EnumConstant (c, target_type);
 274                         }
 275
 276                         return Reduce (ec, target_type);
 277                 }
 278
 279
 280                 public virtual DecimalConstant ConvertToDecimal ()
 281                 {
 282                         return null;
 283                 }
 284
 285                 public virtual DoubleConstant ConvertToDouble ()
 286                 {
 287                         return null;
 288                 }
 289
 290                 public virtual FloatConstant ConvertToFloat ()
 291                 {
 292                         return null;
 293                 }
 294
 295                 public virtual ULongConstant ConvertToULong ()
 296                 {
 297                         return null;
 298                 }
 299
 300                 public virtual LongConstant ConvertToLong ()
 301                 {
 302                         return null;
 303                 }
 304
 305                 public virtual UIntConstant ConvertToUInt ()
 306                 {
 307                         return null;
 308                 }
 309
 310                 public virtual IntConstant ConvertToInt ()
 311                 {
 312                         return null;
 313                 }
 314
 315                 public abstract Constant Increment ();
 316
 317                 public abstract bool IsDefaultValue {
 318                         get;
 319                 }
 320
 321                 public abstract bool IsNegative {
 322                         get;
 323                 }
 324
 325                 //
 326                 // Returns true iff 1) the stack type of this is one of Object,
 327                 // int32, int64 and 2) this == 0 or this == null.
 328                 //
 329                 public virtual bool IsZeroInteger {
 330                         get { return false; }
 331                 }
 332         }
 333
 334         public class BoolConstant : Constant {
 335                 public readonly bool Value;
 336
 337                 public BoolConstant (bool val, Location loc):
 338                         base (loc)
 339                 {
 340                         type = TypeManager.bool_type;
 341                         eclass = ExprClass.Value;
 342
 343                         Value = val;
 344                 }
 345
 346                 override public string AsString ()
 347                 {
 348                         return Value ? "true" : "false";
 349                 }
 350
 351                 public override object GetValue ()
 352                 {
 353                         return (object) Value;
 354                 }
 355
 356
 357                 public override void Emit (EmitContext ec)
 358                 {
 359                         if (Value)
 360                                 ec.ig.Emit (OpCodes.Ldc_I4_1);
 361                         else
 362                                 ec.ig.Emit (OpCodes.Ldc_I4_0);
 363                 }
 364
 365                 public override Constant Increment ()
 366                 {
 367                         throw new NotSupportedException ();
 368                 }
 369
 370                 public override bool IsDefaultValue {
 371                         get {
 372                                 return !Value;
 373                         }
 374                 }
 375
 376                 public override bool IsNegative {
 377                         get {
 378                                 return false;
 379                         }
 380                 }
 381
 382                 public override bool IsZeroInteger {
 383                         get { return Value == false; }
 384                 }
 385
 386                 public override Constant Reduce (EmitContext ec, Type target_type)
 387                 {
 388                         return null;
 389                 }
 390
 391         }
 392
 393         public class ByteConstant : Constant {
 394                 public readonly byte Value;
 395
 396                 public ByteConstant (byte v, Location loc):
 397                         base (loc)
 398                 {
 399                         type = TypeManager.byte_type;
 400                         eclass = ExprClass.Value;
 401                         Value = v;
 402                 }
 403
 404                 public override void Emit (EmitContext ec)
 405                 {
 406                         IntLiteral.EmitInt (ec.ig, Value);
 407                 }
 408
 409                 public override string AsString ()
 410                 {
 411                         return Value.ToString ();
 412                 }
 413
 414                 public override object GetValue ()
 415                 {
 416                         return Value;
 417                 }
 418
 419                 public override DoubleConstant ConvertToDouble ()
 420                 {
 421                         return new DoubleConstant (Value, loc);
 422                 }
 423
 424                 public override FloatConstant ConvertToFloat ()
 425                 {
 426                         return new FloatConstant (Value, loc);
 427                 }
 428
 429                 public override ULongConstant ConvertToULong ()
 430                 {
 431                         return new ULongConstant (Value, loc);
 432                 }
 433
 434                 public override LongConstant ConvertToLong ()
 435                 {
 436                         return new LongConstant (Value, loc);
 437                 }
 438
 439                 public override UIntConstant ConvertToUInt ()
 440                 {
 441                         return new UIntConstant (Value, loc);
 442                 }
 443
 444                 public override IntConstant ConvertToInt ()
 445                 {
 446                         return new IntConstant (Value, loc);
 447                 }
 448
 449                 public override Constant Increment ()
 450                 {
 451                         return new ByteConstant (checked ((byte)(Value + 1)), loc);
 452                 }
 453
 454                 public override bool IsDefaultValue {
 455                         get {
 456                                 return Value == 0;
 457                         }
 458                 }
 459
 460                 public override bool IsNegative {
 461                         get {
 462                                 return false;
 463                         }
 464                 }
 465
 466                 public override bool IsZeroInteger {
 467                         get { return Value == 0; }
 468                 }
 469
 470                 public override Constant Reduce (EmitContext ec, Type target_type)
 471                 {
 472                         if (target_type == TypeManager.sbyte_type) {
 473                                 CheckRange (ec, Value, SByte.MinValue, SByte.MaxValue);
 474                                 return new SByteConstant ((sbyte) Value, Location);
 475                         }
 476                         if (target_type == TypeManager.short_type)
 477                                 return new ShortConstant ((short) Value, Location);
 478                         if (target_type == TypeManager.ushort_type)
 479                                 return new UShortConstant ((ushort) Value, Location);
 480                         if (target_type == TypeManager.int32_type)
 481                                 return new IntConstant ((int) Value, Location);
 482                         if (target_type == TypeManager.uint32_type)
 483                                 return new UIntConstant ((uint) Value, Location);
 484                         if (target_type == TypeManager.int64_type)
 485                                 return new LongConstant ((long) Value, Location);
 486                         if (target_type == TypeManager.uint64_type)
 487                                 return new ULongConstant ((ulong) Value, Location);
 488                         if (target_type == TypeManager.float_type)
 489                                 return new FloatConstant ((float) Value, Location);
 490                         if (target_type == TypeManager.double_type)
 491                                 return new DoubleConstant ((double) Value, Location);
 492                         if (target_type == TypeManager.char_type)
 493                                 return new CharConstant ((char) Value, Location);
 494                         if (target_type == TypeManager.decimal_type)
 495                                 return new DecimalConstant ((decimal) Value, Location);
 496
 497                         return null;
 498                 }
 499
 500         }
 501
 502         public class CharConstant : Constant {
 503                 public readonly char Value;
 504
 505                 public CharConstant (char v, Location loc):
 506                         base (loc)
 507                 {
 508                         type = TypeManager.char_type;
 509                         eclass = ExprClass.Value;
 510                         Value = v;
 511                 }
 512
 513                 public override void Emit (EmitContext ec)
 514                 {
 515                         IntLiteral.EmitInt (ec.ig, Value);
 516                 }
 517
 518                 static public string descape (char c)
 519                 {
 520                         switch (c){
 521                         case '\a':
 522                                 return "\\a";
 523                         case '\b':
 524                                 return "\\b";
 525                         case '\n':
 526                                 return "\\n";
 527                         case '\t':
 528                                 return "\\t";
 529                         case '\v':
 530                                 return "\\v";
 531                         case '\r':
 532                                 return "\\r";
 533                         case '\\':
 534                                 return "\\\\";
 535                         case '\f':
 536                                 return "\\f";
 537                         case '\0':
 538                                 return "\\0";
 539                         case '"':
 540                                 return "\\\"";
 541                         case '\'':
 542                                 return "\\\'";
 543                         }
 544                         return c.ToString ();
 545                 }
 546
 547                 public override string AsString ()
 548                 {
 549                         return "\"" + descape (Value) + "\"";
 550                 }
 551
 552                 public override object GetValue ()
 553                 {
 554                         return Value;
 555                 }
 556
 557                 public override DoubleConstant ConvertToDouble ()
 558                 {
 559                         return new DoubleConstant (Value, loc);
 560                 }
 561
 562                 public override FloatConstant ConvertToFloat ()
 563                 {
 564                         return new FloatConstant (Value, loc);
 565                 }
 566
 567                 public override ULongConstant ConvertToULong ()
 568                 {
 569                         return new ULongConstant (Value, loc);
 570                 }
 571
 572                 public override LongConstant ConvertToLong ()
 573                 {
 574                         return new LongConstant (Value, loc);
 575                 }
 576
 577                 public override UIntConstant ConvertToUInt ()
 578                 {
 579                         return new UIntConstant (Value, loc);
 580                 }
 581
 582                 public override IntConstant ConvertToInt ()
 583                 {
 584                         return new IntConstant (Value, loc);
 585                 }
 586
 587                 public override Constant Increment ()
 588                 {
 589                         return new CharConstant (checked ((char)(Value + 1)), loc);
 590                 }
 591
 592                 public override bool IsDefaultValue {
 593                         get {
 594                                 return Value == 0;
 595                         }
 596                 }
 597
 598                 public override bool IsNegative {
 599                         get {
 600                                 return false;
 601                         }
 602                 }
 603
 604                 public override bool IsZeroInteger {
 605                         get { return Value == '\0'; }
 606                 }
 607
 608                 public override Constant Reduce (EmitContext ec, Type target_type)
 609                 {
 610                         if (target_type == TypeManager.byte_type) {
 611                                 CheckRange (ec, Value, Byte.MinValue, Byte.MaxValue);
 612                                 return new ByteConstant ((byte) Value, Location);
 613                         }
 614                         if (target_type == TypeManager.sbyte_type) {
 615                                 CheckRange (ec, Value, SByte.MinValue, SByte.MaxValue);
 616                                 return new SByteConstant ((sbyte) Value, Location);
 617                         }
 618                         if (target_type == TypeManager.short_type) {
 619                                 CheckRange (ec, Value, Int16.MinValue, Int16.MaxValue);
 620                                 return new ShortConstant ((short) Value, Location);
 621                         }
 622                         if (target_type == TypeManager.int32_type)
 623                                 return new IntConstant ((int) Value, Location);
 624                         if (target_type == TypeManager.uint32_type)
 625                                 return new UIntConstant ((uint) Value, Location);
 626                         if (target_type == TypeManager.int64_type)
 627                                 return new LongConstant ((long) Value, Location);
 628                         if (target_type == TypeManager.uint64_type)
 629                                 return new ULongConstant ((ulong) Value, Location);
 630                         if (target_type == TypeManager.float_type)
 631                                 return new FloatConstant ((float) Value, Location);
 632                         if (target_type == TypeManager.double_type)
 633                                 return new DoubleConstant ((double) Value, Location);
 634                         if (target_type == TypeManager.decimal_type)
 635                                 return new DecimalConstant ((decimal) Value, Location);
 636
 637                         return null;
 638                 }
 639
 640         }
 641
 642         public class SByteConstant : Constant {
 643                 public readonly sbyte Value;
 644
 645                 public SByteConstant (sbyte v, Location loc):
 646                         base (loc)
 647                 {
 648                         type = TypeManager.sbyte_type;
 649                         eclass = ExprClass.Value;
 650                         Value = v;
 651                 }
 652
 653                 public override void Emit (EmitContext ec)
 654                 {
 655                         IntLiteral.EmitInt (ec.ig, Value);
 656                 }
 657
 658                 public override string AsString ()
 659                 {
 660                         return Value.ToString ();
 661                 }
 662
 663                 public override object GetValue ()
 664                 {
 665                         return Value;
 666                 }
 667
 668                 public override DoubleConstant ConvertToDouble ()
 669                 {
 670                         return new DoubleConstant (Value, loc);
 671                 }
 672
 673                 public override FloatConstant ConvertToFloat ()
 674                 {
 675                         return new FloatConstant (Value, loc);
 676                 }
 677
 678                 public override ULongConstant ConvertToULong ()
 679                 {
 680                         if (Value >= 0)
 681                                 return new ULongConstant ((ulong) Value, loc);
 682
 683                         return null;
 684                 }
 685
 686                 public override LongConstant ConvertToLong ()
 687                 {
 688                         return new LongConstant (Value, loc);
 689                 }
 690
 691                 public override UIntConstant ConvertToUInt ()
 692                 {
 693                         return null;
 694                 }
 695
 696                 public override IntConstant ConvertToInt ()
 697                 {
 698                         return new IntConstant (Value, loc);
 699                 }
 700
 701                 public override Constant Increment ()
 702                 {
 703                     return new SByteConstant (checked((sbyte)(Value + 1)), loc);
 704                 }
 705
 706                 public override bool IsDefaultValue {
 707                         get {
 708                                 return Value == 0;
 709                         }
 710                 }
 711
 712                 public override bool IsNegative {
 713                         get {
 714                                 return Value < 0;
 715                         }
 716                 }
 717
 718                 public override bool IsZeroInteger {
 719                         get { return Value == 0; }
 720                 }
 721
 722                 public override Constant Reduce (EmitContext ec, Type target_type)
 723                 {
 724                         if (target_type == TypeManager.byte_type) {
 725                                 CheckUnsigned (ec, Value);
 726                                 return new ByteConstant ((byte) Value, Location);
 727                         }
 728                         if (target_type == TypeManager.short_type)
 729                                 return new ShortConstant ((short) Value, Location);
 730                         if (target_type == TypeManager.ushort_type) {
 731                                 CheckUnsigned (ec, Value);
 732                                 return new UShortConstant ((ushort) Value, Location);
 733                         } if (target_type == TypeManager.int32_type)
 734                                   return new IntConstant ((int) Value, Location);
 735                         if (target_type == TypeManager.uint32_type) {
 736                                 CheckUnsigned (ec, Value);
 737                                 return new UIntConstant ((uint) Value, Location);
 738                         } if (target_type == TypeManager.int64_type)
 739                                   return new LongConstant ((long) Value, Location);
 740                         if (target_type == TypeManager.uint64_type) {
 741                                 CheckUnsigned (ec, Value);
 742                                 return new ULongConstant ((ulong) Value, Location);
 743                         }
 744                         if (target_type == TypeManager.float_type)
 745                                 return new FloatConstant ((float) Value, Location);
 746                         if (target_type == TypeManager.double_type)
 747                                 return new DoubleConstant ((double) Value, Location);
 748                         if (target_type == TypeManager.char_type) {
 749                                 CheckUnsigned (ec, Value);
 750                                 return new CharConstant ((char) Value, Location);
 751                         }
 752                         if (target_type == TypeManager.decimal_type)
 753                                 return new DecimalConstant ((decimal) Value, Location);
 754
 755                         return null;
 756                 }
 757
 758         }
 759
 760         public class ShortConstant : Constant {
 761                 public readonly short Value;
 762
 763                 public ShortConstant (short v, Location loc):
 764                         base (loc)
 765                 {
 766                         type = TypeManager.short_type;
 767                         eclass = ExprClass.Value;
 768                         Value = v;
 769                 }
 770
 771                 public override void Emit (EmitContext ec)
 772                 {
 773                         IntLiteral.EmitInt (ec.ig, Value);
 774                 }
 775
 776                 public override string AsString ()
 777                 {
 778                         return Value.ToString ();
 779                 }
 780
 781                 public override object GetValue ()
 782                 {
 783                         return Value;
 784                 }
 785
 786                 public override DoubleConstant ConvertToDouble ()
 787                 {
 788                         return new DoubleConstant (Value, loc);
 789                 }
 790
 791                 public override FloatConstant ConvertToFloat ()
 792                 {
 793                         return new FloatConstant (Value, loc);
 794                 }
 795
 796                 public override ULongConstant ConvertToULong ()
 797                 {
 798                         return null;
 799                 }
 800
 801                 public override LongConstant ConvertToLong ()
 802                 {
 803                         return new LongConstant (Value, loc);
 804                 }
 805
 806                 public override UIntConstant ConvertToUInt ()
 807                 {
 808                         return null;
 809                 }
 810
 811                 public override IntConstant ConvertToInt ()
 812                 {
 813                         return new IntConstant (Value, loc);
 814                 }
 815
 816                 public override Constant Increment ()
 817                 {
 818                         return new ShortConstant (checked((short)(Value + 1)), loc);
 819                 }
 820
 821                 public override bool IsDefaultValue {
 822                         get {
 823                                 return Value == 0;
 824                         }
 825                 }
 826
 827                 public override bool IsZeroInteger {
 828                         get { return Value == 0; }
 829                 }
 830
 831                 public override bool IsNegative {
 832                         get {
 833                                 return Value < 0;
 834                         }
 835                 }
 836
 837                 public override Constant Reduce (EmitContext ec, Type target_type)
 838                 {
 839                         if (target_type == TypeManager.byte_type) {
 840                                 CheckRange (ec, Value, Byte.MinValue, Byte.MaxValue);
 841                                 return new ByteConstant ((byte) Value, Location);
 842                         }
 843                         if (target_type == TypeManager.sbyte_type) {
 844                                 CheckRange (ec, Value, SByte.MinValue, SByte.MaxValue);
 845                                 return new SByteConstant ((sbyte) Value, Location);
 846                         }
 847                         if (target_type == TypeManager.ushort_type) {
 848                                 CheckUnsigned (ec, Value);
 849                                 return new UShortConstant ((ushort) Value, Location);
 850                         }
 851                         if (target_type == TypeManager.int32_type)
 852                                 return new IntConstant ((int) Value, Location);
 853                         if (target_type == TypeManager.uint32_type) {
 854                                 CheckUnsigned (ec, Value);
 855                                 return new UIntConstant ((uint) Value, Location);
 856                         }
 857                         if (target_type == TypeManager.int64_type)
 858                                 return new LongConstant ((long) Value, Location);
 859                         if (target_type == TypeManager.uint64_type) {
 860                                 CheckUnsigned (ec, Value);
 861                                 return new ULongConstant ((ulong) Value, Location);
 862                         }
 863                         if (target_type == TypeManager.float_type)
 864                                 return new FloatConstant ((float) Value, Location);
 865                         if (target_type == TypeManager.double_type)
 866                                 return new DoubleConstant ((double) Value, Location);
 867                         if (target_type == TypeManager.char_type) {
 868                                 CheckRange (ec, Value, Char.MinValue, Char.MaxValue);
 869                                 return new CharConstant ((char) Value, Location);
 870                         }
 871                         if (target_type == TypeManager.decimal_type)
 872                                 return new DecimalConstant ((decimal) Value, Location);
 873
 874                         return null;
 875                 }
 876
 877         }
 878
 879         public class UShortConstant : Constant {
 880                 public readonly ushort Value;
 881
 882                 public UShortConstant (ushort v, Location loc):
 883                         base (loc)
 884                 {
 885                         type = TypeManager.ushort_type;
 886                         eclass = ExprClass.Value;
 887                         Value = v;
 888                 }
 889
 890                 public override void Emit (EmitContext ec)
 891                 {
 892                         IntLiteral.EmitInt (ec.ig, Value);
 893                 }
 894
 895                 public override string AsString ()
 896                 {
 897                         return Value.ToString ();
 898                 }
 899
 900                 public override object GetValue ()
 901                 {
 902                         return Value;
 903                 }
 904
 905                 public override DoubleConstant ConvertToDouble ()
 906                 {
 907                         return new DoubleConstant (Value, loc);
 908                 }
 909
 910                 public override FloatConstant ConvertToFloat ()
 911                 {
 912                         return new FloatConstant (Value, loc);
 913                 }
 914
 915                 public override ULongConstant ConvertToULong ()
 916                 {
 917                         return new ULongConstant (Value, loc);
 918                 }
 919
 920                 public override LongConstant ConvertToLong ()
 921                 {
 922                         return new LongConstant (Value, loc);
 923                 }
 924
 925                 public override UIntConstant ConvertToUInt ()
 926                 {
 927                         return new UIntConstant (Value, loc);
 928                 }
 929
 930                 public override IntConstant ConvertToInt ()
 931                 {
 932                         return new IntConstant (Value, loc);
 933                 }
 934
 935                 public override Constant Increment ()
 936                 {
 937                         return new UShortConstant (checked((ushort)(Value + 1)), loc);
 938                 }
 939
 940                 public override bool IsDefaultValue {
 941                         get {
 942                                 return Value == 0;
 943                         }
 944                 }
 945
 946                 public override bool IsNegative {
 947                         get {
 948                                 return false;
 949                         }
 950                 }
 951
 952                 public override bool IsZeroInteger {
 953                         get { return Value == 0; }
 954                 }
 955
 956                 public override Constant Reduce (EmitContext ec, Type target_type)
 957                 {
 958                         if (target_type == TypeManager.byte_type) {
 959                                 CheckRange (ec, Value, Byte.MinValue, Byte.MaxValue);
 960                                 return new ByteConstant ((byte) Value, Location);
 961                         }
 962                         if (target_type == TypeManager.sbyte_type) {
 963                                 CheckRange (ec, Value, SByte.MinValue, SByte.MaxValue);
 964                                 return new SByteConstant ((sbyte) Value, Location);
 965                         }
 966                         if (target_type == TypeManager.short_type) {
 967                                 CheckRange (ec, Value, Int16.MinValue, Int16.MaxValue);
 968                                 return new ShortConstant ((short) Value, Location);
 969                         }
 970                         if (target_type == TypeManager.int32_type)
 971                                 return new IntConstant ((int) Value, Location);
 972                         if (target_type == TypeManager.uint32_type)
 973                                 return new UIntConstant ((uint) Value, Location);
 974                         if (target_type == TypeManager.int64_type)
 975                                 return new LongConstant ((long) Value, Location);
 976                         if (target_type == TypeManager.uint64_type)
 977                                 return new ULongConstant ((ulong) Value, Location);
 978                         if (target_type == TypeManager.float_type)
 979                                 return new FloatConstant ((float) Value, Location);
 980                         if (target_type == TypeManager.double_type)
 981                                 return new DoubleConstant ((double) Value, Location);
 982                         if (target_type == TypeManager.char_type) {
 983                                 CheckRange (ec, Value, Char.MinValue, Char.MaxValue);
 984                                 return new CharConstant ((char) Value, Location);
 985                         }
 986                         if (target_type == TypeManager.decimal_type)
 987                                 return new DecimalConstant ((decimal) Value, Location);
 988
 989                         return null;
 990                 }
 991         }
 992
 993         public class IntConstant : Constant {
 994                 public readonly int Value;
 995
 996                 public IntConstant (int v, Location loc):
 997                         base (loc)
 998                 {
 999                         type = TypeManager.int32_type;
1000                         eclass = ExprClass.Value;
1001                         Value = v;
1002                 }
1003
1004                 static public void EmitInt (ILGenerator ig, int i)
1005                 {
1006                         switch (i){
1007                         case -1:
1008                                 ig.Emit (OpCodes.Ldc_I4_M1);
1009                                 break;
1010
1011                         case 0:
1012                                 ig.Emit (OpCodes.Ldc_I4_0);
1013                                 break;
1014
1015                         case 1:
1016                                 ig.Emit (OpCodes.Ldc_I4_1);
1017                                 break;
1018
1019                         case 2:
1020                                 ig.Emit (OpCodes.Ldc_I4_2);
1021                                 break;
1022
1023                         case 3:
1024                                 ig.Emit (OpCodes.Ldc_I4_3);
1025                                 break;
1026
1027                         case 4:
1028                                 ig.Emit (OpCodes.Ldc_I4_4);
1029                                 break;
1030
1031                         case 5:
1032                                 ig.Emit (OpCodes.Ldc_I4_5);
1033                                 break;
1034
1035                         case 6:
1036                                 ig.Emit (OpCodes.Ldc_I4_6);
1037                                 break;
1038
1039                         case 7:
1040                                 ig.Emit (OpCodes.Ldc_I4_7);
1041                                 break;
1042
1043                         case 8:
1044                                 ig.Emit (OpCodes.Ldc_I4_8);
1045                                 break;
1046
1047                         default:
1048                                 if (i >= -128 && i <= 127){
1049                                         ig.Emit (OpCodes.Ldc_I4_S, (sbyte) i);
1050                                 } else
1051                                         ig.Emit (OpCodes.Ldc_I4, i);
1052                                 break;
1053                         }
1054                 }
1055
1056                 public override void Emit (EmitContext ec)
1057                 {
1058                         EmitInt (ec.ig, Value);
1059                 }
1060
1061                 public override string AsString ()
1062                 {
1063                         return Value.ToString ();
1064                 }
1065
1066                 public override object GetValue ()
1067                 {
1068                         return Value;
1069                 }
1070
1071                 public override DecimalConstant ConvertToDecimal()
1072                 {
1073                         return new DecimalConstant (Value, loc);
1074                 }
1075
1076                 public override DoubleConstant ConvertToDouble ()
1077                 {
1078                         return new DoubleConstant (Value, loc);
1079                 }
1080
1081                 public override FloatConstant ConvertToFloat ()
1082                 {
1083                         return new FloatConstant (Value, loc);
1084                 }
1085
1086                 public override ULongConstant ConvertToULong ()
1087                 {
1088                         if (Value < 0)
1089                                 return null;
1090
1091                         return new ULongConstant ((ulong) Value, loc);
1092                 }
1093
1094                 public override LongConstant ConvertToLong ()
1095                 {
1096                         return new LongConstant (Value, loc);
1097                 }
1098
1099                 public override UIntConstant ConvertToUInt ()
1100                 {
1101                         if (Value < 0)
1102                                 return null;
1103
1104                         return new UIntConstant ((uint) Value, loc);
1105                 }
1106
1107                 public override IntConstant ConvertToInt ()
1108                 {
1109                         return this;
1110                 }
1111
1112                 public override Constant Increment ()
1113                 {
1114                         return new IntConstant (checked(Value + 1), loc);
1115                 }
1116
1117                 public override bool IsDefaultValue {
1118                         get {
1119                                 return Value == 0;
1120                         }
1121                 }
1122
1123                 public override bool IsNegative {
1124                         get {
1125                                 return Value < 0;
1126                         }
1127                 }
1128
1129                 public override bool IsZeroInteger {
1130                         get { return Value == 0; }
1131                 }
1132
1133                 public override Constant Reduce (EmitContext ec, Type target_type)
1134                 {
1135                         if (target_type == TypeManager.byte_type) {
1136                                 CheckRange (ec, Value, Byte.MinValue, Byte.MaxValue);
1137                                 return new ByteConstant ((byte) Value, Location);
1138                         }
1139                         if (target_type == TypeManager.sbyte_type) {
1140                                 CheckRange (ec, Value, SByte.MinValue, SByte.MaxValue);
1141                                 return new SByteConstant ((sbyte) Value, Location);
1142                         }
1143                         if (target_type == TypeManager.short_type) {
1144                                 CheckRange (ec, Value, Int16.MinValue, Int16.MaxValue);
1145                                 return new ShortConstant ((short) Value, Location);
1146                         }
1147                         if (target_type == TypeManager.ushort_type) {
1148                                 CheckRange (ec, Value, UInt16.MinValue, UInt16.MaxValue);
1149                                 return new UShortConstant ((ushort) Value, Location);
1150                         }
1151                         if (target_type == TypeManager.uint32_type) {
1152                                 CheckRange (ec, Value, Int32.MinValue, Int32.MaxValue);
1153                                 return new UIntConstant ((uint) Value, Location);
1154                         }
1155                         if (target_type == TypeManager.int64_type)
1156                                 return new LongConstant ((long) Value, Location);
1157                         if (target_type == TypeManager.uint64_type) {
1158                                 CheckUnsigned (ec, Value);
1159                                 return new ULongConstant ((ulong) Value, Location);
1160                         }
1161                         if (target_type == TypeManager.float_type)
1162                                 return new FloatConstant ((float) Value, Location);
1163                         if (target_type == TypeManager.double_type)
1164                                 return new DoubleConstant ((double) Value, Location);
1165                         if (target_type == TypeManager.char_type) {
1166                                 CheckRange (ec, Value, Char.MinValue, Char.MaxValue);
1167                                 return new CharConstant ((char) Value, Location);
1168                         }
1169                         if (target_type == TypeManager.decimal_type)
1170                                 return new DecimalConstant ((decimal) Value, Location);
1171
1172                         return null;
1173                 }
1174         }
1175
1176         public class UIntConstant : Constant {
1177                 public readonly uint Value;
1178
1179                 public UIntConstant (uint v, Location loc):
1180                         base (loc)
1181                 {
1182                         type = TypeManager.uint32_type;
1183                         eclass = ExprClass.Value;
1184                         Value = v;
1185                 }
1186
1187                 public override void Emit (EmitContext ec)
1188                 {
1189                         IntLiteral.EmitInt (ec.ig, unchecked ((int) Value));
1190                 }
1191
1192                 public override string AsString ()
1193                 {
1194                         return Value.ToString ();
1195                 }
1196
1197                 public override object GetValue ()
1198                 {
1199                         return Value;
1200                 }
1201
1202                 public override DoubleConstant ConvertToDouble ()
1203                 {
1204                         return new DoubleConstant (Value, loc);
1205                 }
1206
1207                 public override FloatConstant ConvertToFloat ()
1208                 {
1209                         return new FloatConstant (Value, loc);
1210                 }
1211
1212                 public override ULongConstant ConvertToULong ()
1213                 {
1214                         return new ULongConstant (Value, loc);
1215                 }
1216
1217                 public override LongConstant ConvertToLong ()
1218                 {
1219                         return new LongConstant (Value, loc);
1220                 }
1221
1222                 public override UIntConstant ConvertToUInt ()
1223                 {
1224                         return this;
1225                 }
1226
1227                 public override IntConstant ConvertToInt ()
1228                 {
1229                         return null;
1230                 }
1231
1232                 public override Constant Increment ()
1233                 {
1234                         return new UIntConstant (checked(Value + 1), loc);
1235                 }
1236
1237                 public override bool IsDefaultValue {
1238                         get {
1239                                 return Value == 0;
1240                         }
1241                 }
1242
1243                 public override bool IsNegative {
1244                         get {
1245                                 return false;
1246                         }
1247                 }
1248
1249                 public override bool IsZeroInteger {
1250                         get { return Value == 0; }
1251                 }
1252
1253                 public override Constant Reduce (EmitContext ec, Type target_type)
1254                 {
1255                         if (target_type == TypeManager.byte_type) {
1256                                 CheckRange (ec, Value, Char.MinValue, Char.MaxValue);
1257                                 return new ByteConstant ((byte) Value, Location);
1258                         }
1259                         if (target_type == TypeManager.sbyte_type) {
1260                                 CheckRange (ec, Value, SByte.MinValue, SByte.MaxValue);
1261                                 return new SByteConstant ((sbyte) Value, Location);
1262                         }
1263                         if (target_type == TypeManager.short_type) {
1264                                 CheckRange (ec, Value, Int16.MinValue, Int16.MaxValue);
1265                                 return new ShortConstant ((short) Value, Location);
1266                         }
1267                         if (target_type == TypeManager.ushort_type) {
1268                                 CheckRange (ec, Value, UInt16.MinValue, UInt16.MaxValue);
1269                                 return new UShortConstant ((ushort) Value, Location);
1270                         }
1271                         if (target_type == TypeManager.int32_type) {
1272                                 CheckRange (ec, Value, Int32.MinValue, Int32.MaxValue);
1273                                 return new IntConstant ((int) Value, Location);
1274                         }
1275                         if (target_type == TypeManager.int64_type)
1276                                 return new LongConstant ((long) Value, Location);
1277                         if (target_type == TypeManager.uint64_type)
1278                                 return new ULongConstant ((ulong) Value, Location);
1279                         if (target_type == TypeManager.float_type)
1280                                 return new FloatConstant ((float) Value, Location);
1281                         if (target_type == TypeManager.double_type)
1282                                 return new DoubleConstant ((double) Value, Location);
1283                         if (target_type == TypeManager.char_type) {
1284                                 CheckRange (ec, Value, Char.MinValue, Char.MaxValue);
1285                                 return new CharConstant ((char) Value, Location);
1286                         }
1287                         if (target_type == TypeManager.decimal_type)
1288                                 return new DecimalConstant ((decimal) Value, Location);
1289
1290                         return null;
1291                 }
1292
1293         }
1294
1295         public class LongConstant : Constant {
1296                 public readonly long Value;
1297
1298                 public LongConstant (long v, Location loc):
1299                         base (loc)
1300                 {
1301                         type = TypeManager.int64_type;
1302                         eclass = ExprClass.Value;
1303                         Value = v;
1304                 }
1305
1306                 public override void Emit (EmitContext ec)
1307                 {
1308                         ILGenerator ig = ec.ig;
1309
1310                         EmitLong (ig, Value);
1311                 }
1312
1313                 static public void EmitLong (ILGenerator ig, long l)
1314                 {
1315                         if ((l >> 32) == 0){
1316                                 IntLiteral.EmitInt (ig, unchecked ((int) l));
1317                                 ig.Emit (OpCodes.Conv_U8);
1318                         } else {
1319                                 ig.Emit (OpCodes.Ldc_I8, l);
1320                         }
1321                 }
1322
1323                 public override string AsString ()
1324                 {
1325                         return Value.ToString ();
1326                 }
1327
1328                 public override object GetValue ()
1329                 {
1330                         return Value;
1331                 }
1332
1333                 public override DoubleConstant ConvertToDouble ()
1334                 {
1335                         return new DoubleConstant (Value, loc);
1336                 }
1337
1338                 public override FloatConstant ConvertToFloat ()
1339                 {
1340                         return new FloatConstant (Value, loc);
1341                 }
1342
1343                 public override ULongConstant ConvertToULong ()
1344                 {
1345                         if (Value < 0)
1346                                 return null;
1347
1348                         return new ULongConstant ((ulong) Value, loc);
1349                 }
1350
1351                 public override LongConstant ConvertToLong ()
1352                 {
1353                         return this;
1354                 }
1355
1356                 public override UIntConstant ConvertToUInt ()
1357                 {
1358                         return null;
1359                 }
1360
1361                 public override IntConstant ConvertToInt ()
1362                 {
1363                         return null;
1364                 }
1365
1366                 public override Constant Increment ()
1367                 {
1368                         return new LongConstant (checked(Value + 1), loc);
1369                 }
1370
1371                 public override bool IsDefaultValue {
1372                         get {
1373                                 return Value == 0;
1374                         }
1375                 }
1376
1377                 public override bool IsNegative {
1378                         get {
1379                                 return Value < 0;
1380                         }
1381                 }
1382
1383                 public override bool IsZeroInteger {
1384                         get { return Value == 0; }
1385                 }
1386
1387                 public override Constant Reduce (EmitContext ec, Type target_type)
1388                 {
1389                         if (target_type == TypeManager.byte_type) {
1390                                 CheckRange (ec, Value, Byte.MinValue, Byte.MaxValue);
1391                                 return new ByteConstant ((byte) Value, Location);
1392                         }
1393                         if (target_type == TypeManager.sbyte_type) {
1394                                 CheckRange (ec, Value, SByte.MinValue, SByte.MaxValue);
1395                                 return new SByteConstant ((sbyte) Value, Location);
1396                         }
1397                         if (target_type == TypeManager.short_type) {
1398                                 CheckRange (ec, Value, Int16.MinValue, Int16.MaxValue);
1399                                 return new ShortConstant ((short) Value, Location);
1400                         }
1401                         if (target_type == TypeManager.ushort_type) {
1402                                 CheckRange (ec, Value, UInt16.MinValue, UInt16.MaxValue);
1403                                 return new UShortConstant ((ushort) Value, Location);
1404                         }
1405                         if (target_type == TypeManager.int32_type) {
1406                                 CheckRange (ec, Value, Int32.MinValue, Int32.MaxValue);
1407                                 return new IntConstant ((int) Value, Location);
1408                         }
1409                         if (target_type == TypeManager.uint32_type) {
1410                                 CheckRange (ec, Value, UInt32.MinValue, UInt32.MaxValue);
1411                                 return new UIntConstant ((uint) Value, Location);
1412                         }
1413                         if (target_type == TypeManager.uint64_type) {
1414                                 CheckUnsigned (ec, Value);
1415                                 return new ULongConstant ((ulong) Value, Location);
1416                         }
1417                         if (target_type == TypeManager.float_type)
1418                                 return new FloatConstant ((float) Value, Location);
1419                         if (target_type == TypeManager.double_type)
1420                                 return new DoubleConstant ((double) Value, Location);
1421                         if (target_type == TypeManager.char_type) {
1422                                 CheckRange (ec, Value, Char.MinValue, Char.MaxValue);
1423                                 return new CharConstant ((char) Value, Location);
1424                         }
1425                         if (target_type == TypeManager.decimal_type)
1426                                 return new DecimalConstant ((decimal) Value, Location);
1427
1428                         return null;
1429                 }
1430
1431         }
1432
1433         public class ULongConstant : Constant {
1434                 public readonly ulong Value;
1435
1436                 public ULongConstant (ulong v, Location loc):
1437                         base (loc)
1438                 {
1439                         type = TypeManager.uint64_type;
1440                         eclass = ExprClass.Value;
1441                         Value = v;
1442                 }
1443
1444                 public override void Emit (EmitContext ec)
1445                 {
1446                         ILGenerator ig = ec.ig;
1447
1448                         LongLiteral.EmitLong (ig, unchecked ((long) Value));
1449                 }
1450
1451                 public override string AsString ()
1452                 {
1453                         return Value.ToString ();
1454                 }
1455
1456                 public override object GetValue ()
1457                 {
1458                         return Value;
1459                 }
1460
1461                 public override DoubleConstant ConvertToDouble ()
1462                 {
1463                         return new DoubleConstant (Value, loc);
1464                 }
1465
1466                 public override FloatConstant ConvertToFloat ()
1467                 {
1468                         return new FloatConstant (Value, loc);
1469                 }
1470
1471                 public override ULongConstant ConvertToULong ()
1472                 {
1473                         return this;
1474                 }
1475
1476                 public override LongConstant ConvertToLong ()
1477                 {
1478                         return null;
1479                 }
1480
1481                 public override UIntConstant ConvertToUInt ()
1482                 {
1483                         return null;
1484                 }
1485
1486                 public override IntConstant ConvertToInt ()
1487                 {
1488                         return null;
1489                 }
1490
1491                 public override Constant Increment ()
1492                 {
1493                         return new ULongConstant (checked(Value + 1), loc);
1494                 }
1495
1496                 public override bool IsDefaultValue {
1497                         get {
1498                                 return Value == 0;
1499                         }
1500                 }
1501
1502                 public override bool IsNegative {
1503                         get {
1504                                 return false;
1505                         }
1506                 }
1507
1508                 public override bool IsZeroInteger {
1509                         get { return Value == 0; }
1510                 }
1511
1512                 public override Constant Reduce (EmitContext ec, Type target_type)
1513                 {
1514                         if (target_type == TypeManager.byte_type) {
1515                                 CheckRange (ec, Value, Byte.MaxValue);
1516                                 return new ByteConstant ((byte) Value, Location);
1517                         }
1518                         if (target_type == TypeManager.sbyte_type) {
1519                                 CheckRange (ec, Value, (ulong) SByte.MaxValue);
1520                                 return new SByteConstant ((sbyte) Value, Location);
1521                         }
1522                         if (target_type == TypeManager.short_type) {
1523                                 CheckRange (ec, Value, (ulong) Int16.MaxValue);
1524                                 return new ShortConstant ((short) Value, Location);
1525                         }
1526                         if (target_type == TypeManager.ushort_type) {
1527                                 CheckRange (ec, Value, UInt16.MaxValue);
1528                                 return new UShortConstant ((ushort) Value, Location);
1529                         }
1530                         if (target_type == TypeManager.int32_type) {
1531                                 CheckRange (ec, Value, Int32.MaxValue);
1532                                 return new IntConstant ((int) Value, Location);
1533                         }
1534                         if (target_type == TypeManager.uint32_type) {
1535                                 CheckRange (ec, Value, UInt32.MaxValue);
1536                                 return new UIntConstant ((uint) Value, Location);
1537                         }
1538                         if (target_type == TypeManager.int64_type) {
1539                                 CheckRange (ec, Value, (ulong) Int64.MaxValue);
1540                                 return new LongConstant ((long) Value, Location);
1541                         }
1542                         if (target_type == TypeManager.float_type)
1543                                 return new FloatConstant ((float) Value, Location);
1544                         if (target_type == TypeManager.double_type)
1545                                 return new DoubleConstant ((double) Value, Location);
1546                         if (target_type == TypeManager.char_type) {
1547                                 CheckRange (ec, Value, Char.MaxValue);
1548                                 return new CharConstant ((char) Value, Location);
1549                         }
1550                         if (target_type == TypeManager.decimal_type)
1551                                 return new DecimalConstant ((decimal) Value, Location);
1552
1553                         return null;
1554                 }
1555
1556         }
1557
1558         public class FloatConstant : Constant {
1559                 public readonly float Value;
1560
1561                 public FloatConstant (float v, Location loc):
1562                         base (loc)
1563                 {
1564                         type = TypeManager.float_type;
1565                         eclass = ExprClass.Value;
1566                         Value = v;
1567                 }
1568
1569                 public override void Emit (EmitContext ec)
1570                 {
1571                         ec.ig.Emit (OpCodes.Ldc_R4, Value);
1572                 }
1573
1574                 public override string AsString ()
1575                 {
1576                         return Value.ToString ();
1577                 }
1578
1579                 public override object GetValue ()
1580                 {
1581                         return Value;
1582                 }
1583
1584                 public override DoubleConstant ConvertToDouble ()
1585                 {
1586                         return new DoubleConstant (Value, loc);
1587                 }
1588
1589                 public override FloatConstant ConvertToFloat ()
1590                 {
1591                         return this;
1592                 }
1593
1594                 public override LongConstant ConvertToLong ()
1595                 {
1596                         return null;
1597                 }
1598
1599                 public override UIntConstant ConvertToUInt ()
1600                 {
1601                         return null;
1602                 }
1603
1604                 public override IntConstant ConvertToInt ()
1605                 {
1606                         return null;
1607                 }
1608
1609                 public override Constant Increment ()
1610                 {
1611                         return new FloatConstant (checked(Value + 1), loc);
1612                 }
1613
1614                 public override bool IsDefaultValue {
1615                         get {
1616                                 return Value == 0;
1617                         }
1618                 }
1619
1620                 public override bool IsNegative {
1621                         get {
1622                                 return Value < 0;
1623                         }
1624                 }
1625
1626                 public override Constant Reduce (EmitContext ec, Type target_type)
1627                 {
1628                         if (target_type == TypeManager.byte_type)
1629                                 return new ByteConstant ((byte) Value, Location);
1630                         if (target_type == TypeManager.sbyte_type)
1631                                 return new SByteConstant ((sbyte) Value, Location);
1632                         if (target_type == TypeManager.short_type)
1633                                 return new ShortConstant ((short) Value, Location);
1634                         if (target_type == TypeManager.ushort_type)
1635                                 return new UShortConstant ((ushort) Value, Location);
1636                         if (target_type == TypeManager.int32_type)
1637                                 return new IntConstant ((int) Value, Location);
1638                         if (target_type == TypeManager.uint32_type)
1639                                 return new UIntConstant ((uint) Value, Location);
1640                         if (target_type == TypeManager.int64_type)
1641                                 return new LongConstant ((long) Value, Location);
1642                         if (target_type == TypeManager.uint64_type)
1643                                 return new ULongConstant ((ulong) Value, Location);
1644                         if (target_type == TypeManager.double_type)
1645                                 return new DoubleConstant ((double) Value, Location);
1646                         if (target_type == TypeManager.char_type)
1647                                 return new CharConstant ((char) Value, Location);
1648                         if (target_type == TypeManager.decimal_type)
1649                                 return new DecimalConstant ((decimal) Value, Location);
1650
1651                         return null;
1652                 }
1653
1654         }
1655
1656         public class DoubleConstant : Constant {
1657                 public readonly double Value;
1658
1659                 public DoubleConstant (double v, Location loc):
1660                         base (loc)
1661                 {
1662                         type = TypeManager.double_type;
1663                         eclass = ExprClass.Value;
1664                         Value = v;
1665                 }
1666
1667                 public override void Emit (EmitContext ec)
1668                 {
1669                         ec.ig.Emit (OpCodes.Ldc_R8, Value);
1670                 }
1671
1672                 public override string AsString ()
1673                 {
1674                         return Value.ToString ();
1675                 }
1676
1677                 public override object GetValue ()
1678                 {
1679                         return Value;
1680                 }
1681
1682                 public override DoubleConstant ConvertToDouble ()
1683                 {
1684                         return this;
1685                 }
1686
1687                 public override FloatConstant ConvertToFloat ()
1688                 {
1689                         return null;
1690                 }
1691
1692                 public override ULongConstant ConvertToULong ()
1693                 {
1694                         return null;
1695                 }
1696
1697                 public override LongConstant ConvertToLong ()
1698                 {
1699                         return null;
1700                 }
1701
1702                 public override UIntConstant ConvertToUInt ()
1703                 {
1704                         return null;
1705                 }
1706
1707                 public override IntConstant ConvertToInt ()
1708                 {
1709                         return null;
1710                 }
1711
1712                 public override Constant Increment ()
1713                 {
1714                         return new DoubleConstant (checked(Value + 1), loc);
1715                 }
1716
1717                 public override bool IsDefaultValue {
1718                         get {
1719                                 return Value == 0;
1720                         }
1721                 }
1722
1723                 public override bool IsNegative {
1724                         get {
1725                                 return Value < 0;
1726                         }
1727                 }
1728
1729                 public override Constant Reduce (EmitContext ec, Type target_type)
1730                 {
1731                         if (target_type == TypeManager.byte_type) {
1732                                 CheckRange (ec, Value, Byte.MinValue, Byte.MaxValue);
1733                                 return new ByteConstant ((byte) Value, Location);
1734                         }
1735                         if (target_type == TypeManager.sbyte_type) {
1736                                 CheckRange (ec, Value, SByte.MinValue, SByte.MaxValue);
1737                                 return new SByteConstant ((sbyte) Value, Location);
1738                         }
1739                         if (target_type == TypeManager.short_type)
1740                                 return new ShortConstant ((short) Value, Location);
1741                         if (target_type == TypeManager.ushort_type)
1742                                 return new UShortConstant ((ushort) Value, Location);
1743                         if (target_type == TypeManager.int32_type)
1744                                 return new IntConstant ((int) Value, Location);
1745                         if (target_type == TypeManager.uint32_type)
1746                                 return new UIntConstant ((uint) Value, Location);
1747                         if (target_type == TypeManager.int64_type)
1748                                 return new LongConstant ((long) Value, Location);
1749                         if (target_type == TypeManager.uint64_type)
1750                                 return new ULongConstant ((ulong) Value, Location);
1751                         if (target_type == TypeManager.float_type)
1752                                 return new FloatConstant ((float) Value, Location);
1753                         if (target_type == TypeManager.char_type) {
1754                                 CheckRange (ec, Value, char.MinValue, char.MaxValue);
1755                                 return new CharConstant ((char) Value, Location);
1756                         }
1757                         if (target_type == TypeManager.decimal_type)
1758                                 return new DecimalConstant ((decimal) Value, Location);
1759
1760                         return null;
1761                 }
1762
1763         }
1764
1765         public class DecimalConstant : Constant {
1766                 public readonly decimal Value;
1767
1768                 public DecimalConstant (decimal d, Location loc):
1769                         base (loc)
1770                 {
1771                         type = TypeManager.decimal_type;
1772                         eclass = ExprClass.Value;
1773                         Value = d;
1774                 }
1775
1776                 override public string AsString ()
1777                 {
1778                         return Value.ToString ();
1779                 }
1780
1781                 public override object GetValue ()
1782                 {
1783                         return (object) Value;
1784                 }
1785
1786                 public override void Emit (EmitContext ec)
1787                 {
1788                         ILGenerator ig = ec.ig;
1789
1790                         int [] words = Decimal.GetBits (Value);
1791                         int power = (words [3] >> 16) & 0xff;
1792
1793                         if (power == 0 && Value <= int.MaxValue && Value >= int.MinValue)
1794                         {
1795                                 IntConstant.EmitInt (ig, (int)Value);
1796                                 ig.Emit (OpCodes.Newobj, TypeManager.void_decimal_ctor_int_arg);
1797                                 return;
1798                         }
1799
1800
1801                         //
1802                         // FIXME: we could optimize this, and call a better
1803                         // constructor
1804                         //
1805
1806                         IntConstant.EmitInt (ig, words [0]);
1807                         IntConstant.EmitInt (ig, words [1]);
1808                         IntConstant.EmitInt (ig, words [2]);
1809
1810                         // sign
1811                         IntConstant.EmitInt (ig, words [3] >> 31);
1812
1813                         // power
1814                         IntConstant.EmitInt (ig, power);
1815
1816                         ig.Emit (OpCodes.Newobj, TypeManager.void_decimal_ctor_five_args);
1817                 }
1818
1819                 public override Constant Increment ()
1820                 {
1821                         return new DecimalConstant (checked (Value + 1), loc);
1822                 }
1823
1824                 public override bool IsDefaultValue {
1825                         get {
1826                                 return Value == 0;
1827                         }
1828                 }
1829
1830                 public override bool IsNegative {
1831                         get {
1832                                 return Value < 0;
1833                         }
1834                 }
1835
1836                 public override Constant Reduce (EmitContext ec, Type target_type)
1837                 {
1838                         if (target_type == TypeManager.sbyte_type)
1839                                 return new SByteConstant ((sbyte)Value, loc);
1840                         if (target_type == TypeManager.byte_type)
1841                                 return new ByteConstant ((byte)Value, loc);
1842                         if (target_type == TypeManager.short_type)
1843                                 return new ShortConstant ((short)Value, loc);
1844                         if (target_type == TypeManager.ushort_type)
1845                                 return new UShortConstant ((ushort)Value, loc);
1846                         if (target_type == TypeManager.int32_type)
1847                                 return new IntConstant ((int)Value, loc);
1848                         if (target_type == TypeManager.uint32_type)
1849                                 return new UIntConstant ((uint)Value, loc);
1850                         if (target_type == TypeManager.int64_type)
1851                                 return new LongConstant ((long)Value, loc);
1852                         if (target_type == TypeManager.uint64_type)
1853                                 return new ULongConstant ((ulong)Value, loc);
1854                         if (target_type == TypeManager.char_type)
1855                                 return new CharConstant ((char)Value, loc);
1856                         if (target_type == TypeManager.float_type)
1857                                 return new FloatConstant ((float)Value, loc);
1858                         if (target_type == TypeManager.double_type)
1859                                 return new DoubleConstant ((double)Value, loc);
1860
1861                         return null;
1862                 }
1863
1864         }
1865
1866         public class StringConstant : Constant {
1867                 public readonly string Value;
1868
1869                 public StringConstant (string s, Location loc):
1870                         base (loc)
1871                 {
1872                         type = TypeManager.string_type;
1873                         eclass = ExprClass.Value;
1874                         Value = s;
1875                 }
1876
1877                 // FIXME: Escape the string.
1878                 override public string AsString ()
1879                 {
1880                         return "\"" + Value + "\"";
1881                 }
1882
1883                 public override object GetValue ()
1884                 {
1885                         return Value;
1886                 }
1887
1888                 public override void Emit (EmitContext ec)
1889                 {
1890                         if (Value == null)
1891                                 ec.ig.Emit (OpCodes.Ldnull);
1892                         else
1893                                 ec.ig.Emit (OpCodes.Ldstr, Value);
1894                 }
1895
1896                 public override Constant Increment ()
1897                 {
1898                         throw new NotSupportedException ();
1899                 }
1900
1901                 public override bool IsDefaultValue {
1902                         get {
1903                                 return Value == null;
1904                         }
1905                 }
1906
1907                 public override bool IsNegative {
1908                         get {
1909                                 return false;
1910                         }
1911                 }
1912
1913                 public override Constant Reduce (EmitContext ec, Type target_type)
1914                 {
1915                         return null;
1916                 }
1917         }
1918
1919 }
1920
1921