mcs/mcs/dynamic.cs

   1 //
   2 // dynamic.cs: support for dynamic expressions
   3 //
   4 // Authors: Marek Safar (marek.safar@gmail.com)
   5 //
   6 // Dual licensed under the terms of the MIT X11 or GNU GPL
   7 //
   8 // Copyright 2009 Novell, Inc
   9 //
  10
  11 using System;
  12 using System.Collections;
  13 using System.Reflection.Emit;
  14
  15 #if NET_4_0
  16 using System.Dynamic;
  17 using SLE = System.Linq.Expressions;
  18 #endif
  19
  20 namespace Mono.CSharp
  21 {
  22         //
  23         // A copy of Microsoft.CSharp/Microsoft.CSharp.RuntimeBinder/CSharpBinderFlags.cs
  24         // has to be kept in sync
  25         //
  26         [Flags]
  27         public enum CSharpBinderFlags
  28         {
  29                 None = 0,
  30                 CheckedContext = 1,
  31                 InvokeSimpleName = 1 << 1,
  32                 InvokeSpecialName = 1 << 2,
  33                 BinaryOperationLogical = 1 << 3,
  34                 ConvertExplicit = 1 << 4,
  35                 ConvertArrayIndex = 1 << 5,
  36                 ResultIndexed = 1 << 6,
  37                 ValueFromCompoundAssignment = 1 << 7,
  38                 ResultDiscarded = 1 << 8
  39         }
  40
  41         //
  42         // Type expression with internal dynamic type symbol
  43         //
  44         class DynamicTypeExpr : TypeExpr
  45         {
  46                 public DynamicTypeExpr (Location loc)
  47                 {
  48                         this.loc = loc;
  49
  50                         type = InternalType.Dynamic;
  51                         eclass = ExprClass.Type;
  52                 }
  53
  54                 public override bool CheckAccessLevel (IMemberContext ds)
  55                 {
  56                         return true;
  57                 }
  58
  59                 protected override TypeExpr DoResolveAsTypeStep (IMemberContext ec)
  60                 {
  61                         return this;
  62                 }
  63         }
  64
  65         //
  66         // Expression created from runtime dynamic object value
  67         //
  68         public class RuntimeValueExpression : Expression, IDynamicAssign, IMemoryLocation
  69         {
  70 #if !NET_4_0
  71                 public class DynamicMetaObject { public Type RuntimeType; }
  72 #endif
  73
  74                 readonly DynamicMetaObject obj;
  75
  76                 public RuntimeValueExpression (DynamicMetaObject obj)
  77                 {
  78                         this.obj = obj;
  79                         this.type = obj.RuntimeType;
  80                         this.eclass = ExprClass.Variable;
  81                 }
  82
  83                 public void AddressOf (EmitContext ec, AddressOp mode)
  84                 {
  85                         throw new NotImplementedException ();
  86                 }
  87
  88                 public override Expression CreateExpressionTree (ResolveContext ec)
  89                 {
  90                         throw new NotImplementedException ();
  91                 }
  92
  93                 public override Expression DoResolve (ResolveContext ec)
  94                 {
  95                         return this;
  96                 }
  97
  98                 public override Expression DoResolveLValue (ResolveContext ec, Expression right_side)
  99                 {
 100                         return this;
 101                 }
 102
 103                 public override void Emit (EmitContext ec)
 104                 {
 105                         throw new NotImplementedException ();
 106                 }
 107
 108                 #region IAssignMethod Members
 109
 110                 public void Emit (EmitContext ec, bool leave_copy)
 111                 {
 112                         throw new NotImplementedException ();
 113                 }
 114
 115                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
 116                 {
 117                         throw new NotImplementedException ();
 118                 }
 119
 120                 #endregion
 121
 122 #if NET_4_0
 123                 public SLE.Expression MakeAssignExpression (BuilderContext ctx)
 124                 {
 125                         return obj.Expression;
 126                 }
 127
 128                 public override SLE.Expression MakeExpression (BuilderContext ctx)
 129                 {
 130                         return SLE.Expression.Convert (obj.Expression, type);
 131                 }
 132 #endif
 133
 134                 public DynamicMetaObject MetaObject {
 135                         get { return obj; }
 136                 }
 137         }
 138
 139         //
 140         // Creates dynamic binder expression
 141         //
 142         interface IDynamicBinder
 143         {
 144                 Expression CreateCallSiteBinder (ResolveContext ec, Arguments args);
 145         }
 146
 147         //
 148         // Extends standard assignment interface for expressions
 149         // supported by dynamic resolver
 150         //
 151         interface IDynamicAssign : IAssignMethod
 152         {
 153 #if NET_4_0
 154                 SLE.Expression MakeAssignExpression (BuilderContext ctx);
 155 #endif
 156         }
 157
 158         //
 159         // Base dynamic expression statement creator
 160         //
 161         class DynamicExpressionStatement : ExpressionStatement
 162         {
 163                 class StaticDataClass : CompilerGeneratedClass
 164                 {
 165                         public StaticDataClass ()
 166                                 : base (new RootDeclSpace (new NamespaceEntry (null, null, null)),
 167                                         new MemberName (CompilerGeneratedClass.MakeName (null, "c", "DynamicSites", 0)),
 168                                         Modifiers.INTERNAL | Modifiers.STATIC)
 169                         {
 170                                 ModFlags &= ~Modifiers.SEALED;
 171                         }
 172                 }
 173
 174                 //
 175                 // Binder flag dynamic constant, the value is combination of
 176                 // flags known at resolve stage and flags known only at emit
 177                 // stage
 178                 //
 179                 protected class BinderFlags : EnumConstant
 180                 {
 181                         DynamicExpressionStatement statement;
 182                         CSharpBinderFlags flags;
 183
 184                         public BinderFlags (CSharpBinderFlags flags, DynamicExpressionStatement statement)
 185                                 : base ()
 186                         {
 187                                 this.flags = flags;
 188                                 this.statement = statement;
 189                         }
 190
 191                         public override Expression DoResolve (ResolveContext ec)
 192                         {
 193                                 Child = new IntConstant ((int) (flags | statement.flags), statement.loc);
 194
 195                                 type = TypeManager.binder_flags;
 196                                 eclass = Child.eclass;
 197                                 return this;
 198                         }
 199                 }
 200
 201                 static StaticDataClass global_site_container;
 202                 static int field_counter;
 203                 static int container_counter;
 204
 205                 readonly Arguments arguments;
 206                 protected IDynamicBinder binder;
 207                 protected Expression binder_expr;
 208
 209                 // Used by BinderFlags
 210                 protected CSharpBinderFlags flags;
 211
 212                 public DynamicExpressionStatement (IDynamicBinder binder, Arguments args, Location loc)
 213                 {
 214                         this.binder = binder;
 215                         this.arguments = args;
 216                         this.loc = loc;
 217                 }
 218
 219                 public Arguments Arguments {
 220                         get {
 221                                 return arguments;
 222                         }
 223                 }
 224
 225                 static TypeContainer CreateSiteContainer ()
 226                 {
 227                         if (global_site_container == null) {
 228                                 global_site_container = new StaticDataClass ();
 229                                 RootContext.ToplevelTypes.AddCompilerGeneratedClass (global_site_container);
 230                                 global_site_container.DefineType ();
 231                                 global_site_container.Define ();
 232 //                              global_site_container.EmitType ();
 233
 234                                 RootContext.RegisterCompilerGeneratedType (global_site_container.TypeBuilder);
 235                         }
 236
 237                         return global_site_container;
 238                 }
 239
 240                 static Field CreateSiteField (FullNamedExpression type)
 241                 {
 242                         TypeContainer site_container = CreateSiteContainer ();
 243                         Field f = new Field (site_container, type, Modifiers.PUBLIC | Modifiers.STATIC,
 244                                 new MemberName ("Site" +  field_counter++), null);
 245                         f.Define ();
 246
 247                         site_container.AddField (f);
 248                         return f;
 249                 }
 250
 251                 public override Expression CreateExpressionTree (ResolveContext ec)
 252                 {
 253                         ec.Report.Error (1963, loc, "An expression tree cannot contain a dynamic operation");
 254                         return null;
 255                 }
 256
 257                 public override Expression DoResolve (ResolveContext ec)
 258                 {
 259                         if (eclass != ExprClass.Invalid)
 260                                 return this;
 261
 262                         if (DoResolveCore (ec))
 263                                 binder_expr = binder.CreateCallSiteBinder (ec, arguments);
 264
 265                         return this;
 266                 }
 267
 268                 protected bool DoResolveCore (ResolveContext rc)
 269                 {
 270                         int errors = rc.Report.Errors;
 271
 272                         if (TypeManager.call_site_type == null)
 273                                 TypeManager.call_site_type = TypeManager.CoreLookupType (rc.Compiler,
 274                                         "System.Runtime.CompilerServices", "CallSite", Kind.Class, true);
 275
 276                         if (TypeManager.generic_call_site_type == null)
 277                                 TypeManager.generic_call_site_type = TypeManager.CoreLookupType (rc.Compiler,
 278                                         "System.Runtime.CompilerServices", "CallSite`1", Kind.Class, true);
 279
 280                         if (TypeManager.binder_type == null) {
 281                                 var t = TypeManager.CoreLookupType (rc.Compiler,
 282                                         "Microsoft.CSharp.RuntimeBinder", "Binder", Kind.Class, true);
 283                                 if (t != null)
 284                                         TypeManager.binder_type = new TypeExpression (t, Location.Null);
 285                         }
 286
 287                         if (TypeManager.binder_flags == null) {
 288                                 TypeManager.binder_flags = TypeManager.CoreLookupType (rc.Compiler,
 289                                         "Microsoft.CSharp.RuntimeBinder", "CSharpBinderFlags", Kind.Enum, true);
 290                         }
 291
 292                         eclass = ExprClass.Value;
 293
 294                         if (type == null)
 295                                 type = InternalType.Dynamic;
 296
 297                         return rc.Report.Errors == errors;
 298                 }
 299
 300                 public override void Emit (EmitContext ec)
 301                 {
 302                         EmitCall (ec, binder_expr, arguments,  false);
 303                 }
 304
 305                 public override void EmitStatement (EmitContext ec)
 306                 {
 307                         EmitCall (ec, binder_expr, arguments, true);
 308                 }
 309
 310                 protected void EmitCall (EmitContext ec, Expression binder, Arguments arguments, bool isStatement)
 311                 {
 312                         int dyn_args_count = arguments == null ? 0 : arguments.Count;
 313                         TypeExpr site_type = CreateSiteType (RootContext.ToplevelTypes.Compiler, arguments, dyn_args_count, isStatement);
 314                         FieldExpr site_field_expr = new FieldExpr (CreateSiteField (site_type).FieldBuilder, loc);
 315
 316                         SymbolWriter.OpenCompilerGeneratedBlock (ec.ig);
 317
 318                         Arguments args = new Arguments (1);
 319                         args.Add (new Argument (binder));
 320                         StatementExpression s = new StatementExpression (new SimpleAssign (site_field_expr, new Invocation (new MemberAccess (site_type, "Create"), args)));
 321
 322                         BlockContext bc = new BlockContext (ec.MemberContext, null, TypeManager.void_type);
 323                         if (s.Resolve (bc)) {
 324                                 Statement init = new If (new Binary (Binary.Operator.Equality, site_field_expr, new NullLiteral (loc)), s, loc);
 325                                 init.Emit (ec);
 326                         }
 327
 328                         args = new Arguments (1 + dyn_args_count);
 329                         args.Add (new Argument (site_field_expr));
 330                         if (arguments != null) {
 331                                 foreach (Argument a in arguments) {
 332                                         if (a is NamedArgument) {
 333                                                 // Name is not valid in this context
 334                                                 args.Add (new Argument (a.Expr, a.ArgType));
 335                                                 continue;
 336                                         }
 337
 338                                         args.Add (a);
 339                                 }
 340                         }
 341
 342                         Expression target = new DelegateInvocation (new MemberAccess (site_field_expr, "Target", loc).Resolve (bc), args, loc).Resolve (bc);
 343                         if (target != null)
 344                                 target.Emit (ec);
 345
 346                         SymbolWriter.CloseCompilerGeneratedBlock (ec.ig);
 347                 }
 348
 349                 public static MemberAccess GetBinderNamespace (Location loc)
 350                 {
 351                         return new MemberAccess (new MemberAccess (
 352                                 new QualifiedAliasMember (QualifiedAliasMember.GlobalAlias, "Microsoft", loc), "CSharp", loc), "RuntimeBinder", loc);
 353                 }
 354
 355                 public static MemberAccess GetBinder (string name, Location loc)
 356                 {
 357                         return new MemberAccess (TypeManager.binder_type, name, loc);
 358                 }
 359
 360                 TypeExpr CreateSiteType (CompilerContext ctx, Arguments arguments, int dyn_args_count, bool is_statement)
 361                 {
 362                         int default_args = is_statement ? 1 : 2;
 363
 364                         bool has_ref_out_argument = false;
 365                         FullNamedExpression[] targs = new FullNamedExpression[dyn_args_count + default_args];
 366                         targs [0] = new TypeExpression (TypeManager.call_site_type, loc);
 367                         for (int i = 0; i < dyn_args_count; ++i) {
 368                                 Type arg_type;
 369                                 Argument a = arguments [i];
 370                                 if (a.Type == TypeManager.null_type)
 371                                         arg_type = TypeManager.object_type;
 372                                 else
 373                                         arg_type = TypeManager.TypeToReflectionType (a.Type);
 374
 375                                 if (a.ArgType == Argument.AType.Out || a.ArgType == Argument.AType.Ref)
 376                                         has_ref_out_argument = true;
 377
 378                                 targs [i + 1] = new TypeExpression (arg_type, loc);
 379                         }
 380
 381                         TypeExpr del_type = null;
 382                         if (!has_ref_out_argument) {
 383                                 string d_name = is_statement ? "Action`" : "Func`";
 384
 385                                 Type t = TypeManager.CoreLookupType (ctx, "System", d_name + (dyn_args_count + default_args), Kind.Delegate, false);
 386                                 if (t != null) {
 387                                         if (!is_statement)
 388                                                 targs [targs.Length - 1] = new TypeExpression (TypeManager.TypeToReflectionType (type), loc);
 389
 390                                         del_type = new GenericTypeExpr (t, new TypeArguments (targs), loc);
 391                                 }
 392                         }
 393
 394                         //
 395                         // Create custom delegate when no appropriate predefined one is found
 396                         //
 397                         if (del_type == null) {
 398                                 Type rt = is_statement ? TypeManager.void_type : type;
 399                                 Parameter[] p = new Parameter [dyn_args_count + 1];
 400                                 p[0] = new Parameter (targs [0], "p0", Parameter.Modifier.NONE, null, loc);
 401
 402                                 for (int i = 1; i < dyn_args_count + 1; ++i)
 403                                         p[i] = new Parameter (targs[i], "p" + i.ToString ("X"), arguments[i - 1].Modifier, null, loc);
 404
 405                                 TypeContainer parent = CreateSiteContainer ();
 406                                 Delegate d = new Delegate (parent.NamespaceEntry, parent, new TypeExpression (TypeManager.TypeToReflectionType (rt), loc),
 407                                         Modifiers.INTERNAL | Modifiers.COMPILER_GENERATED,
 408                                         new MemberName ("Container" + container_counter++.ToString ("X")),
 409                                         new ParametersCompiled (p), null);
 410
 411                                 d.DefineType ();
 412                                 d.Define ();
 413
 414                                 parent.AddDelegate (d);
 415                                 del_type = new TypeExpression (d.TypeBuilder, loc);
 416                         }
 417
 418                         TypeExpr site_type = new GenericTypeExpr (TypeManager.generic_call_site_type, new TypeArguments (del_type), loc);
 419                         return site_type;
 420                 }
 421
 422                 public static void Reset ()
 423                 {
 424                         global_site_container = null;
 425                         field_counter = container_counter = 0;
 426                 }
 427         }
 428
 429         //
 430         // Dynamic member access compound assignment for events
 431         //
 432         class DynamicEventCompoundAssign : DynamicExpressionStatement, IDynamicBinder
 433         {
 434                 string name;
 435                 Statement condition;
 436
 437                 public DynamicEventCompoundAssign (string name, Arguments args, ExpressionStatement assignment, ExpressionStatement invoke, Location loc)
 438                         : base (null, args, loc)
 439                 {
 440                         this.name = name;
 441                         base.binder = this;
 442
 443                         // Used by += or -= only
 444                         type = TypeManager.bool_type;
 445
 446                         condition = new If (
 447                                 new Binary (Binary.Operator.Equality, this, new BoolLiteral (true, loc)),
 448                                 new StatementExpression (invoke), new StatementExpression (assignment),
 449                                 loc);
 450                 }
 451
 452                 public Expression CreateCallSiteBinder (ResolveContext ec, Arguments args)
 453                 {
 454                         Arguments binder_args = new Arguments (3);
 455
 456                         binder_args.Add (new Argument (new BinderFlags (0, this)));
 457                         binder_args.Add (new Argument (new StringLiteral (name, loc)));
 458                         binder_args.Add (new Argument (new TypeOf (new TypeExpression (ec.CurrentType, loc), loc)));
 459
 460                         return new Invocation (GetBinder ("IsEvent", loc), binder_args);
 461                 }
 462
 463                 public override void EmitStatement (EmitContext ec)
 464                 {
 465                         condition.Emit (ec);
 466                 }
 467         }
 468
 469         class DynamicConversion : DynamicExpressionStatement, IDynamicBinder
 470         {
 471                 public DynamicConversion (Type targetType, CSharpBinderFlags flags, Arguments args, Location loc)
 472                         : base (null, args, loc)
 473                 {
 474                         type = targetType;
 475                         base.flags = flags;
 476                         base.binder = this;
 477                 }
 478
 479                 public Expression CreateCallSiteBinder (ResolveContext ec, Arguments args)
 480                 {
 481                         Arguments binder_args = new Arguments (2);
 482
 483                         flags |= ec.HasSet (ResolveContext.Options.CheckedScope) ? CSharpBinderFlags.CheckedContext : 0;
 484
 485                         binder_args.Add (new Argument (new BinderFlags (flags, this)));
 486                         binder_args.Add (new Argument (new TypeOf (new TypeExpression (type, loc), loc)));
 487                         return new Invocation (GetBinder ("Convert", loc), binder_args);
 488                 }
 489         }
 490
 491         class DynamicConstructorBinder : DynamicExpressionStatement, IDynamicBinder
 492         {
 493                 public DynamicConstructorBinder (Type type, Arguments args, Location loc)
 494                         : base (null, args, loc)
 495                 {
 496                         this.type = type;
 497                         base.binder = this;
 498                 }
 499
 500                 public Expression CreateCallSiteBinder (ResolveContext ec, Arguments args)
 501                 {
 502                         Arguments binder_args = new Arguments (3);
 503
 504                         binder_args.Add (new Argument (new BinderFlags (0, this)));
 505                         binder_args.Add (new Argument (new TypeOf (new TypeExpression (ec.CurrentType, loc), loc)));
 506                         binder_args.Add (new Argument (new ImplicitlyTypedArrayCreation ("[]", args.CreateDynamicBinderArguments (ec), loc)));
 507
 508                         return new Invocation (GetBinder ("InvokeConstructor", loc), binder_args);
 509                 }
 510         }
 511
 512         class DynamicIndexBinder : DynamicMemberAssignable
 513         {
 514                 public DynamicIndexBinder (Arguments args, Location loc)
 515                         : base (args, loc)
 516                 {
 517                 }
 518
 519                 protected override Expression CreateCallSiteBinder (ResolveContext ec, Arguments args, bool isSet)
 520                 {
 521                         Arguments binder_args = new Arguments (3);
 522
 523                         binder_args.Add (new Argument (new BinderFlags (0, this)));
 524                         binder_args.Add (new Argument (new TypeOf (new TypeExpression (ec.CurrentType, loc), loc)));
 525                         binder_args.Add (new Argument (new ImplicitlyTypedArrayCreation ("[]", args.CreateDynamicBinderArguments (ec), loc)));
 526
 527                         return new Invocation (GetBinder (isSet ? "SetIndex" : "GetIndex", loc), binder_args);
 528                 }
 529         }
 530
 531         class DynamicInvocation : DynamicExpressionStatement, IDynamicBinder
 532         {
 533                 ATypeNameExpression member;
 534
 535                 public DynamicInvocation (ATypeNameExpression member, Arguments args, Location loc)
 536                         : base (null, args, loc)
 537                 {
 538                         base.binder = this;
 539                         this.member = member;
 540                 }
 541
 542                 public DynamicInvocation (ATypeNameExpression member, Arguments args, Type type, Location loc)
 543                         : this (member, args, loc)
 544                 {
 545                         // When a return type is known not to be dynamic
 546                         this.type = type;
 547                 }
 548
 549                 public static DynamicInvocation CreateSpecialNameInvoke (ATypeNameExpression member, Arguments args, Location loc)
 550                 {
 551                         return new DynamicInvocation (member, args, loc) {
 552                                 flags = CSharpBinderFlags.InvokeSpecialName
 553                         };
 554                 }
 555
 556                 public Expression CreateCallSiteBinder (ResolveContext ec, Arguments args)
 557                 {
 558                         Arguments binder_args = new Arguments (member != null ? 5 : 3);
 559                         bool is_member_access = member is MemberAccess;
 560
 561                         CSharpBinderFlags call_flags;
 562                         if (!is_member_access && member is SimpleName) {
 563                                 call_flags = CSharpBinderFlags.InvokeSimpleName;
 564                                 is_member_access = true;
 565                         } else {
 566                                 call_flags = 0;
 567                         }
 568
 569                         binder_args.Add (new Argument (new BinderFlags (call_flags, this)));
 570
 571                         if (is_member_access)
 572                                 binder_args.Add (new Argument (new StringLiteral (member.Name, member.Location)));
 573
 574                         if (member != null && member.HasTypeArguments) {
 575                                 TypeArguments ta = member.TypeArguments;
 576                                 if (ta.Resolve (ec)) {
 577                                         ArrayList targs = new ArrayList (ta.Count);
 578                                         foreach (Type t in ta.Arguments)
 579                                                 targs.Add (new TypeOf (new TypeExpression (t, loc), loc));
 580
 581                                         binder_args.Add (new Argument (new ImplicitlyTypedArrayCreation ("[]", targs, loc)));
 582                                 }
 583                         } else if (is_member_access) {
 584                                 binder_args.Add (new Argument (new NullLiteral (loc)));
 585                         }
 586
 587                         binder_args.Add (new Argument (new TypeOf (new TypeExpression (ec.CurrentType, loc), loc)));
 588
 589                         Expression real_args;
 590                         if (args == null) {
 591                                 // Cannot be null because .NET trips over
 592                                 real_args = new ArrayCreation (new MemberAccess (GetBinderNamespace (loc), "CSharpArgumentInfo", loc), "[]", new ArrayList (0), loc);
 593                         } else {
 594                                 real_args = new ImplicitlyTypedArrayCreation ("[]", args.CreateDynamicBinderArguments (ec), loc);
 595                         }
 596
 597                         binder_args.Add (new Argument (real_args));
 598
 599                         return new Invocation (GetBinder (is_member_access ? "InvokeMember" : "Invoke", loc), binder_args);
 600                 }
 601
 602                 public override void EmitStatement (EmitContext ec)
 603                 {
 604                         flags |= CSharpBinderFlags.ResultDiscarded;
 605                         base.EmitStatement (ec);
 606                 }
 607         }
 608
 609         class DynamicMemberBinder : DynamicMemberAssignable
 610         {
 611                 readonly string name;
 612
 613                 public DynamicMemberBinder (string name, Arguments args, Location loc)
 614                         : base (args, loc)
 615                 {
 616                         this.name = name;
 617                 }
 618
 619                 protected override Expression CreateCallSiteBinder (ResolveContext ec, Arguments args, bool isSet)
 620                 {
 621                         Arguments binder_args = new Arguments (4);
 622
 623                         binder_args.Add (new Argument (new BinderFlags (0, this)));
 624                         binder_args.Add (new Argument (new StringLiteral (name, loc)));
 625                         binder_args.Add (new Argument (new TypeOf (new TypeExpression (ec.CurrentType, loc), loc)));
 626                         binder_args.Add (new Argument (new ImplicitlyTypedArrayCreation ("[]", args.CreateDynamicBinderArguments (ec), loc)));
 627
 628                         return new Invocation (GetBinder (isSet ? "SetMember" : "GetMember", loc), binder_args);
 629                 }
 630         }
 631
 632         //
 633         // Any member binder which can be source and target of assignment
 634         //
 635         abstract class DynamicMemberAssignable : DynamicExpressionStatement, IDynamicBinder, IAssignMethod
 636         {
 637                 Expression setter;
 638                 Arguments setter_args;
 639
 640                 protected DynamicMemberAssignable (Arguments args, Location loc)
 641                         : base (null, args, loc)
 642                 {
 643                         base.binder = this;
 644                 }
 645
 646                 public Expression CreateCallSiteBinder (ResolveContext ec, Arguments args)
 647                 {
 648                         //
 649                         // DoResolve always uses getter
 650                         //
 651                         return CreateCallSiteBinder (ec, args, false);
 652                 }
 653
 654                 protected abstract Expression CreateCallSiteBinder (ResolveContext ec, Arguments args, bool isSet);
 655
 656                 public override Expression DoResolveLValue (ResolveContext rc, Expression right_side)
 657                 {
 658                         if (right_side == EmptyExpression.OutAccess.Instance) {
 659                                 right_side.DoResolveLValue (rc, this);
 660                                 return null;
 661                         }
 662
 663                         if (DoResolveCore (rc)) {
 664                                 setter_args = new Arguments (Arguments.Count + 1);
 665                                 setter_args.AddRange (Arguments);
 666                                 setter_args.Add (new Argument (right_side));
 667                                 setter = CreateCallSiteBinder (rc, setter_args, true);
 668                         }
 669
 670                         eclass = ExprClass.Variable;
 671                         return this;
 672                 }
 673
 674                 public override void Emit (EmitContext ec)
 675                 {
 676                         // It's null for ResolveLValue used without assignment
 677                         if (binder_expr == null)
 678                                 EmitCall (ec, setter, Arguments, false);
 679                         else
 680                                 base.Emit (ec);
 681                 }
 682
 683                 public override void EmitStatement (EmitContext ec)
 684                 {
 685                         // It's null for ResolveLValue used without assignment
 686                         if (binder_expr == null)
 687                                 EmitCall (ec, setter, Arguments, true);
 688                         else
 689                                 base.EmitStatement (ec);
 690                 }
 691
 692                 #region IAssignMethod Members
 693
 694                 public void Emit (EmitContext ec, bool leave_copy)
 695                 {
 696                         throw new NotImplementedException ();
 697                 }
 698
 699                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
 700                 {
 701                         EmitCall (ec, setter, setter_args, !leave_copy);
 702                 }
 703
 704                 #endregion
 705         }
 706
 707         class DynamicUnaryConversion : DynamicExpressionStatement, IDynamicBinder
 708         {
 709                 string name;
 710
 711                 public DynamicUnaryConversion (string name, Arguments args, Location loc)
 712                         : base (null, args, loc)
 713                 {
 714                         this.name = name;
 715                         base.binder = this;
 716                         if (name == "IsTrue" || name == "IsFalse")
 717                                 type = TypeManager.bool_type;
 718                 }
 719
 720                 public Expression CreateCallSiteBinder (ResolveContext ec, Arguments args)
 721                 {
 722                         Arguments binder_args = new Arguments (3);
 723
 724                         MemberAccess sle = new MemberAccess (new MemberAccess (
 725                                 new QualifiedAliasMember (QualifiedAliasMember.GlobalAlias, "System", loc), "Linq", loc), "Expressions", loc);
 726
 727                         var flags = ec.HasSet (ResolveContext.Options.CheckedScope) ? CSharpBinderFlags.CheckedContext : 0;
 728
 729                         binder_args.Add (new Argument (new BinderFlags (flags, this)));
 730                         binder_args.Add (new Argument (new MemberAccess (new MemberAccess (sle, "ExpressionType", loc), name, loc)));
 731                         binder_args.Add (new Argument (new ImplicitlyTypedArrayCreation ("[]", args.CreateDynamicBinderArguments (ec), loc)));
 732
 733                         return new Invocation (GetBinder ("UnaryOperation", loc), binder_args);
 734                 }
 735         }
 736 }