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                 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                         throw new NotImplementedException ();
 254                 }
 255
 256                 public override Expression DoResolve (ResolveContext ec)
 257                 {
 258                         if (eclass != ExprClass.Invalid)
 259                                 return this;
 260
 261                         if (DoResolveCore (ec))
 262                                 binder_expr = binder.CreateCallSiteBinder (ec, arguments);
 263
 264                         return this;
 265                 }
 266
 267                 protected bool DoResolveCore (ResolveContext rc)
 268                 {
 269                         int errors = rc.Report.Errors;
 270
 271                         if (TypeManager.call_site_type == null)
 272                                 TypeManager.call_site_type = TypeManager.CoreLookupType (rc.Compiler,
 273                                         "System.Runtime.CompilerServices", "CallSite", Kind.Class, true);
 274
 275                         if (TypeManager.generic_call_site_type == null)
 276                                 TypeManager.generic_call_site_type = TypeManager.CoreLookupType (rc.Compiler,
 277                                         "System.Runtime.CompilerServices", "CallSite`1", Kind.Class, true);
 278
 279                         if (TypeManager.binder_type == null) {
 280                                 var t = TypeManager.CoreLookupType (rc.Compiler,
 281                                         "Microsoft.CSharp.RuntimeBinder", "Binder", Kind.Class, true);
 282                                 if (t != null)
 283                                         TypeManager.binder_type = new TypeExpression (t, Location.Null);
 284                         }
 285
 286                         if (TypeManager.binder_flags == null) {
 287                                 TypeManager.binder_flags = TypeManager.CoreLookupType (rc.Compiler,
 288                                         "Microsoft.CSharp.RuntimeBinder", "CSharpBinderFlags", Kind.Enum, true);
 289                         }
 290
 291                         eclass = ExprClass.Value;
 292
 293                         if (type == null)
 294                                 type = InternalType.Dynamic;
 295
 296                         return rc.Report.Errors == errors;
 297                 }
 298
 299                 public override void Emit (EmitContext ec)
 300                 {
 301                         EmitCall (ec, binder_expr, arguments,  false);
 302                 }
 303
 304                 public override void EmitStatement (EmitContext ec)
 305                 {
 306                         EmitCall (ec, binder_expr, arguments, true);
 307                 }
 308
 309                 protected void EmitCall (EmitContext ec, Expression binder, Arguments arguments, bool isStatement)
 310                 {
 311                         int dyn_args_count = arguments == null ? 0 : arguments.Count;
 312                         TypeExpr site_type = CreateSiteType (RootContext.ToplevelTypes.Compiler, arguments, dyn_args_count, isStatement);
 313                         FieldExpr site_field_expr = new FieldExpr (CreateSiteField (site_type).FieldBuilder, loc);
 314
 315                         SymbolWriter.OpenCompilerGeneratedBlock (ec.ig);
 316
 317                         Arguments args = new Arguments (1);
 318                         args.Add (new Argument (binder));
 319                         StatementExpression s = new StatementExpression (new SimpleAssign (site_field_expr, new Invocation (new MemberAccess (site_type, "Create"), args)));
 320
 321                         BlockContext bc = new BlockContext (ec.MemberContext, null, TypeManager.void_type);
 322                         if (s.Resolve (bc)) {
 323                                 Statement init = new If (new Binary (Binary.Operator.Equality, site_field_expr, new NullLiteral (loc)), s, loc);
 324                                 init.Emit (ec);
 325                         }
 326
 327                         args = new Arguments (1 + dyn_args_count);
 328                         args.Add (new Argument (site_field_expr));
 329                         if (arguments != null) {
 330                                 foreach (Argument a in arguments) {
 331                                         if (a is NamedArgument) {
 332                                                 // Name is not valid in this context
 333                                                 args.Add (new Argument (a.Expr, a.ArgType));
 334                                                 continue;
 335                                         }
 336
 337                                         args.Add (a);
 338                                 }
 339                         }
 340
 341                         Expression target = new DelegateInvocation (new MemberAccess (site_field_expr, "Target", loc).Resolve (bc), args, loc).Resolve (bc);
 342                         if (target != null)
 343                                 target.Emit (ec);
 344
 345                         SymbolWriter.CloseCompilerGeneratedBlock (ec.ig);
 346                 }
 347
 348                 public static MemberAccess GetBinderNamespace (Location loc)
 349                 {
 350                         return new MemberAccess (new MemberAccess (
 351                                 new QualifiedAliasMember (QualifiedAliasMember.GlobalAlias, "Microsoft", loc), "CSharp", loc), "RuntimeBinder", loc);
 352                 }
 353
 354                 public static MemberAccess GetBinder (string name, Location loc)
 355                 {
 356                         return new MemberAccess (TypeManager.binder_type, name, loc);
 357                 }
 358
 359                 TypeExpr CreateSiteType (CompilerContext ctx, Arguments arguments, int dyn_args_count, bool is_statement)
 360                 {
 361                         int default_args = is_statement ? 1 : 2;
 362
 363                         bool has_ref_out_argument = false;
 364                         FullNamedExpression[] targs = new FullNamedExpression[dyn_args_count + default_args];
 365                         targs [0] = new TypeExpression (TypeManager.call_site_type, loc);
 366                         for (int i = 0; i < dyn_args_count; ++i) {
 367                                 Type arg_type;
 368                                 Argument a = arguments [i];
 369                                 if (a.Type == TypeManager.null_type)
 370                                         arg_type = TypeManager.object_type;
 371                                 else
 372                                         arg_type = TypeManager.TypeToReflectionType (a.Type);
 373
 374                                 if (a.ArgType == Argument.AType.Out || a.ArgType == Argument.AType.Ref)
 375                                         has_ref_out_argument = true;
 376
 377                                 targs [i + 1] = new TypeExpression (arg_type, loc);
 378                         }
 379
 380                         TypeExpr del_type = null;
 381                         if (!has_ref_out_argument) {
 382                                 string d_name = is_statement ? "Action`" : "Func`";
 383
 384                                 Type t = TypeManager.CoreLookupType (ctx, "System", d_name + (dyn_args_count + default_args), Kind.Delegate, false);
 385                                 if (t != null) {
 386                                         if (!is_statement)
 387                                                 targs [targs.Length - 1] = new TypeExpression (TypeManager.TypeToReflectionType (type), loc);
 388
 389                                         del_type = new GenericTypeExpr (t, new TypeArguments (targs), loc);
 390                                 }
 391                         }
 392
 393                         //
 394                         // Create custom delegate when no appropriate predefined one is found
 395                         //
 396                         if (del_type == null) {
 397                                 Type rt = is_statement ? TypeManager.void_type : type;
 398                                 Parameter[] p = new Parameter [dyn_args_count + 1];
 399                                 p[0] = new Parameter (targs [0], "p0", Parameter.Modifier.NONE, null, loc);
 400
 401                                 for (int i = 1; i < dyn_args_count + 1; ++i)
 402                                         p[i] = new Parameter (targs[i], "p" + i.ToString ("X"), arguments[i - 1].Modifier, null, loc);
 403
 404                                 TypeContainer parent = CreateSiteContainer ();
 405                                 Delegate d = new Delegate (parent.NamespaceEntry, parent, new TypeExpression (TypeManager.TypeToReflectionType (rt), loc),
 406                                         Modifiers.INTERNAL | Modifiers.COMPILER_GENERATED,
 407                                         new MemberName ("Container" + container_counter++.ToString ("X")),
 408                                         new ParametersCompiled (p), null);
 409
 410                                 d.DefineType ();
 411                                 d.Define ();
 412
 413                                 parent.AddDelegate (d);
 414                                 del_type = new TypeExpression (d.TypeBuilder, loc);
 415                         }
 416
 417                         TypeExpr site_type = new GenericTypeExpr (TypeManager.generic_call_site_type, new TypeArguments (del_type), loc);
 418                         return site_type;
 419                 }
 420
 421                 public static void Reset ()
 422                 {
 423                         global_site_container = null;
 424                         field_counter = container_counter = 0;
 425                 }
 426         }
 427
 428         //
 429         // Dynamic member access compound assignment for events
 430         //
 431         class DynamicEventCompoundAssign : DynamicExpressionStatement, IDynamicBinder
 432         {
 433                 string name;
 434                 ExpressionStatement assignment;
 435                 ExpressionStatement invoke;
 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                         this.assignment = assignment;
 442                         this.invoke = invoke;
 443                         base.binder = this;
 444
 445                         // Used by += or -= only
 446                         type = TypeManager.bool_type;
 447                 }
 448
 449                 public Expression CreateCallSiteBinder (ResolveContext ec, Arguments args)
 450                 {
 451                         Arguments binder_args = new Arguments (2);
 452
 453                         binder_args.Add (new Argument (new StringLiteral (name, loc)));
 454                         binder_args.Add (new Argument (new TypeOf (new TypeExpression (ec.CurrentType, loc), loc)));
 455
 456                         return new Invocation (GetBinder ("IsEvent", loc), binder_args);
 457                 }
 458
 459                 public override void EmitStatement (EmitContext ec)
 460                 {
 461                         Statement cond = new If (
 462                                 new Binary (Binary.Operator.Equality, this, new BoolLiteral (true, loc)),
 463                                 new StatementExpression (invoke),
 464                                 new StatementExpression (assignment),
 465                                 loc);
 466                         cond.Emit (ec);
 467                 }
 468         }
 469
 470         class DynamicConversion : DynamicExpressionStatement, IDynamicBinder
 471         {
 472                 public DynamicConversion (Type targetType, CSharpBinderFlags flags, Arguments args, Location loc)
 473                         : base (null, args, loc)
 474                 {
 475                         type = targetType;
 476                         base.flags = flags;
 477                         base.binder = this;
 478                 }
 479
 480                 public Expression CreateCallSiteBinder (ResolveContext ec, Arguments args)
 481                 {
 482                         Arguments binder_args = new Arguments (2);
 483
 484                         flags |= ec.HasSet (ResolveContext.Options.CheckedScope) ? CSharpBinderFlags.CheckedContext : 0;
 485
 486                         binder_args.Add (new Argument (new BinderFlags (flags, this)));
 487                         binder_args.Add (new Argument (new TypeOf (new TypeExpression (type, loc), loc)));
 488                         return new Invocation (GetBinder ("Convert", loc), binder_args);
 489                 }
 490         }
 491
 492         class DynamicConstructorBinder : DynamicExpressionStatement, IDynamicBinder
 493         {
 494                 public DynamicConstructorBinder (Type type, Arguments args, Location loc)
 495                         : base (null, args, loc)
 496                 {
 497                         this.type = type;
 498                         base.binder = this;
 499                 }
 500
 501                 public Expression CreateCallSiteBinder (ResolveContext ec, Arguments args)
 502                 {
 503                         Arguments binder_args = new Arguments (3);
 504
 505                         binder_args.Add (new Argument (new BinderFlags (0, this)));
 506                         binder_args.Add (new Argument (new TypeOf (new TypeExpression (ec.CurrentType, loc), loc)));
 507                         binder_args.Add (new Argument (new ImplicitlyTypedArrayCreation ("[]", args.CreateDynamicBinderArguments (), loc)));
 508
 509                         return new Invocation (GetBinder ("InvokeConstructor", loc), binder_args);
 510                 }
 511         }
 512
 513         class DynamicIndexBinder : DynamicMemberAssignable
 514         {
 515                 public DynamicIndexBinder (Arguments args, Location loc)
 516                         : base (args, loc)
 517                 {
 518                 }
 519
 520                 protected override Expression CreateCallSiteBinder (ResolveContext ec, Arguments args, bool isSet)
 521                 {
 522                         Arguments binder_args = new Arguments (3);
 523
 524                         binder_args.Add (new Argument (new BinderFlags (0, this)));
 525                         binder_args.Add (new Argument (new TypeOf (new TypeExpression (ec.CurrentType, loc), loc)));
 526                         binder_args.Add (new Argument (new ImplicitlyTypedArrayCreation ("[]", args.CreateDynamicBinderArguments (), loc)));
 527
 528                         return new Invocation (GetBinder (isSet ? "SetIndex" : "GetIndex", loc), binder_args);
 529                 }
 530         }
 531
 532         class DynamicInvocation : DynamicExpressionStatement, IDynamicBinder
 533         {
 534                 ATypeNameExpression member;
 535
 536                 public DynamicInvocation (ATypeNameExpression member, Arguments args, Location loc)
 537                         : base (null, args, loc)
 538                 {
 539                         base.binder = this;
 540                         this.member = member;
 541                 }
 542
 543                 public DynamicInvocation (ATypeNameExpression member, Arguments args, Type type, Location loc)
 544                         : this (member, args, loc)
 545                 {
 546                         // When a return type is known not to be dynamic
 547                         this.type = type;
 548                 }
 549
 550                 public Expression CreateCallSiteBinder (ResolveContext ec, Arguments args)
 551                 {
 552                         Arguments binder_args = new Arguments (member != null ? 5 : 3);
 553                         bool is_member_access = member is MemberAccess;
 554
 555                         CSharpBinderFlags call_flags;
 556                         if (!is_member_access && member is SimpleName) {
 557                                 call_flags = CSharpBinderFlags.InvokeSimpleName;
 558                                 is_member_access = true;
 559                         } else {
 560                                 call_flags = 0;
 561                         }
 562
 563                         binder_args.Add (new Argument (new BinderFlags (call_flags, this)));
 564
 565                         if (is_member_access)
 566                                 binder_args.Add (new Argument (new StringLiteral (member.Name, member.Location)));
 567
 568                         if (member != null && member.HasTypeArguments) {
 569                                 TypeArguments ta = member.TypeArguments;
 570                                 if (ta.Resolve (ec)) {
 571                                         ArrayList targs = new ArrayList (ta.Count);
 572                                         foreach (Type t in ta.Arguments)
 573                                                 targs.Add (new TypeOf (new TypeExpression (t, loc), loc));
 574
 575                                         binder_args.Add (new Argument (new ImplicitlyTypedArrayCreation ("[]", targs, loc)));
 576                                 }
 577                         } else if (is_member_access) {
 578                                 binder_args.Add (new Argument (new NullLiteral (loc)));
 579                         }
 580
 581                         binder_args.Add (new Argument (new TypeOf (new TypeExpression (ec.CurrentType, loc), loc)));
 582
 583                         Expression real_args;
 584                         if (args == null) {
 585                                 // Cannot be null because .NET trips over
 586                                 real_args = new ArrayCreation (new MemberAccess (GetBinderNamespace (loc), "CSharpArgumentInfo", loc), "[]", new ArrayList (0), loc);
 587                         } else {
 588                                 real_args = new ImplicitlyTypedArrayCreation ("[]", args.CreateDynamicBinderArguments (), loc);
 589                         }
 590
 591                         binder_args.Add (new Argument (real_args));
 592
 593                         return new Invocation (GetBinder (is_member_access ? "InvokeMember" : "Invoke", loc), binder_args);
 594                 }
 595
 596                 public override void EmitStatement (EmitContext ec)
 597                 {
 598                         flags = CSharpBinderFlags.ResultDiscarded;
 599                         base.EmitStatement (ec);
 600                 }
 601         }
 602
 603         class DynamicMemberBinder : DynamicMemberAssignable
 604         {
 605                 readonly string name;
 606
 607                 public DynamicMemberBinder (string name, Arguments args, Location loc)
 608                         : base (args, loc)
 609                 {
 610                         this.name = name;
 611                 }
 612
 613                 protected override Expression CreateCallSiteBinder (ResolveContext ec, Arguments args, bool isSet)
 614                 {
 615                         Arguments binder_args = new Arguments (4);
 616
 617                         binder_args.Add (new Argument (new BinderFlags (0, this)));
 618                         binder_args.Add (new Argument (new StringLiteral (name, loc)));
 619                         binder_args.Add (new Argument (new TypeOf (new TypeExpression (ec.CurrentType, loc), loc)));
 620                         binder_args.Add (new Argument (new ImplicitlyTypedArrayCreation ("[]", args.CreateDynamicBinderArguments (), loc)));
 621
 622                         return new Invocation (GetBinder (isSet ? "SetMember" : "GetMember", loc), binder_args);
 623                 }
 624         }
 625
 626         //
 627         // Any member binder which can be source and target of assignment
 628         //
 629         abstract class DynamicMemberAssignable : DynamicExpressionStatement, IDynamicBinder, IAssignMethod
 630         {
 631                 Expression setter;
 632                 Arguments setter_args;
 633
 634                 protected DynamicMemberAssignable (Arguments args, Location loc)
 635                         : base (null, args, loc)
 636                 {
 637                         base.binder = this;
 638                 }
 639
 640                 public Expression CreateCallSiteBinder (ResolveContext ec, Arguments args)
 641                 {
 642                         //
 643                         // DoResolve always uses getter
 644                         //
 645                         return CreateCallSiteBinder (ec, args, false);
 646                 }
 647
 648                 protected abstract Expression CreateCallSiteBinder (ResolveContext ec, Arguments args, bool isSet);
 649
 650                 public override Expression DoResolveLValue (ResolveContext rc, Expression right_side)
 651                 {
 652                         if (DoResolveCore (rc)) {
 653                                 setter_args = new Arguments (Arguments.Count + 1);
 654                                 setter_args.AddRange (Arguments);
 655                                 setter_args.Add (new Argument (right_side));
 656                                 setter = CreateCallSiteBinder (rc, setter_args, true);
 657                         }
 658
 659                         return this;
 660                 }
 661
 662                 #region IAssignMethod Members
 663
 664                 public void Emit (EmitContext ec, bool leave_copy)
 665                 {
 666                         throw new NotImplementedException ();
 667                 }
 668
 669                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
 670                 {
 671                         EmitCall (ec, setter, setter_args, !leave_copy);
 672                 }
 673
 674                 #endregion
 675         }
 676
 677         class DynamicUnaryConversion : DynamicExpressionStatement, IDynamicBinder
 678         {
 679                 string name;
 680
 681                 public DynamicUnaryConversion (string name, Arguments args, Location loc)
 682                         : base (null, args, loc)
 683                 {
 684                         this.name = name;
 685                         base.binder = this;
 686                         if (name == "IsTrue" || name == "IsFalse")
 687                                 type = TypeManager.bool_type;
 688                 }
 689
 690                 public Expression CreateCallSiteBinder (ResolveContext ec, Arguments args)
 691                 {
 692                         Arguments binder_args = new Arguments (3);
 693
 694                         MemberAccess sle = new MemberAccess (new MemberAccess (
 695                                 new QualifiedAliasMember (QualifiedAliasMember.GlobalAlias, "System", loc), "Linq", loc), "Expressions", loc);
 696
 697                         var flags = ec.HasSet (ResolveContext.Options.CheckedScope) ? CSharpBinderFlags.CheckedContext : 0;
 698
 699                         binder_args.Add (new Argument (new BinderFlags (flags, this)));
 700                         binder_args.Add (new Argument (new MemberAccess (new MemberAccess (sle, "ExpressionType", loc), name, loc)));
 701                         binder_args.Add (new Argument (new ImplicitlyTypedArrayCreation ("[]", args.CreateDynamicBinderArguments (), loc)));
 702
 703                         return new Invocation (GetBinder ("UnaryOperation", loc), binder_args);
 704                 }
 705         }
 706 }