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.binder_type == null) {
 273                                 var t = TypeManager.CoreLookupType (rc.Compiler,
 274                                         "Microsoft.CSharp.RuntimeBinder", "Binder", Kind.Class, true);
 275                                 if (t != null)
 276                                         TypeManager.binder_type = new TypeExpression (t, Location.Null);
 277                         }
 278
 279                         if (TypeManager.call_site_type == null)
 280                                 TypeManager.call_site_type = TypeManager.CoreLookupType (rc.Compiler,
 281                                         "System.Runtime.CompilerServices", "CallSite", Kind.Class, true);
 282
 283                         if (TypeManager.generic_call_site_type == null)
 284                                 TypeManager.generic_call_site_type = TypeManager.CoreLookupType (rc.Compiler,
 285                                         "System.Runtime.CompilerServices", "CallSite`1", Kind.Class, true);
 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                         if (rc.Report.Errors == errors)
 298                                 return true;
 299
 300                         rc.Report.Error (1969, loc,
 301                                 "Dynamic operation cannot be compiled without `Microsoft.CSharp.dll' assembly reference");
 302                         return false;
 303                 }
 304
 305                 public override void Emit (EmitContext ec)
 306                 {
 307                         EmitCall (ec, binder_expr, arguments,  false);
 308                 }
 309
 310                 public override void EmitStatement (EmitContext ec)
 311                 {
 312                         EmitCall (ec, binder_expr, arguments, true);
 313                 }
 314
 315                 protected void EmitCall (EmitContext ec, Expression binder, Arguments arguments, bool isStatement)
 316                 {
 317                         int dyn_args_count = arguments == null ? 0 : arguments.Count;
 318                         TypeExpr site_type = CreateSiteType (RootContext.ToplevelTypes.Compiler, arguments, dyn_args_count, isStatement);
 319                         FieldExpr site_field_expr = new FieldExpr (CreateSiteField (site_type).FieldBuilder, loc);
 320
 321                         SymbolWriter.OpenCompilerGeneratedBlock (ec.ig);
 322
 323                         Arguments args = new Arguments (1);
 324                         args.Add (new Argument (binder));
 325                         StatementExpression s = new StatementExpression (new SimpleAssign (site_field_expr, new Invocation (new MemberAccess (site_type, "Create"), args)));
 326
 327                         BlockContext bc = new BlockContext (ec.MemberContext, null, TypeManager.void_type);
 328                         if (s.Resolve (bc)) {
 329                                 Statement init = new If (new Binary (Binary.Operator.Equality, site_field_expr, new NullLiteral (loc)), s, loc);
 330                                 init.Emit (ec);
 331                         }
 332
 333                         args = new Arguments (1 + dyn_args_count);
 334                         args.Add (new Argument (site_field_expr));
 335                         if (arguments != null) {
 336                                 foreach (Argument a in arguments) {
 337                                         if (a is NamedArgument) {
 338                                                 // Name is not valid in this context
 339                                                 args.Add (new Argument (a.Expr, a.ArgType));
 340                                                 continue;
 341                                         }
 342
 343                                         args.Add (a);
 344                                 }
 345                         }
 346
 347                         Expression target = new DelegateInvocation (new MemberAccess (site_field_expr, "Target", loc).Resolve (bc), args, loc).Resolve (bc);
 348                         if (target != null)
 349                                 target.Emit (ec);
 350
 351                         SymbolWriter.CloseCompilerGeneratedBlock (ec.ig);
 352                 }
 353
 354                 public static MemberAccess GetBinderNamespace (Location loc)
 355                 {
 356                         return new MemberAccess (new MemberAccess (
 357                                 new QualifiedAliasMember (QualifiedAliasMember.GlobalAlias, "Microsoft", loc), "CSharp", loc), "RuntimeBinder", loc);
 358                 }
 359
 360                 public static MemberAccess GetBinder (string name, Location loc)
 361                 {
 362                         return new MemberAccess (TypeManager.binder_type, name, loc);
 363                 }
 364
 365                 TypeExpr CreateSiteType (CompilerContext ctx, Arguments arguments, int dyn_args_count, bool is_statement)
 366                 {
 367                         int default_args = is_statement ? 1 : 2;
 368
 369                         bool has_ref_out_argument = false;
 370                         FullNamedExpression[] targs = new FullNamedExpression[dyn_args_count + default_args];
 371                         targs [0] = new TypeExpression (TypeManager.call_site_type, loc);
 372                         for (int i = 0; i < dyn_args_count; ++i) {
 373                                 Type arg_type;
 374                                 Argument a = arguments [i];
 375                                 if (a.Type == TypeManager.null_type)
 376                                         arg_type = TypeManager.object_type;
 377                                 else
 378                                         arg_type = TypeManager.TypeToReflectionType (a.Type);
 379
 380                                 if (a.ArgType == Argument.AType.Out || a.ArgType == Argument.AType.Ref)
 381                                         has_ref_out_argument = true;
 382
 383                                 targs [i + 1] = new TypeExpression (arg_type, loc);
 384                         }
 385
 386                         TypeExpr del_type = null;
 387                         if (!has_ref_out_argument) {
 388                                 string d_name = is_statement ? "Action`" : "Func`";
 389
 390                                 Type t = TypeManager.CoreLookupType (ctx, "System", d_name + (dyn_args_count + default_args), Kind.Delegate, false);
 391                                 if (t != null) {
 392                                         if (!is_statement)
 393                                                 targs [targs.Length - 1] = new TypeExpression (TypeManager.TypeToReflectionType (type), loc);
 394
 395                                         del_type = new GenericTypeExpr (t, new TypeArguments (targs), loc);
 396                                 }
 397                         }
 398
 399                         //
 400                         // Create custom delegate when no appropriate predefined one is found
 401                         //
 402                         if (del_type == null) {
 403                                 Type rt = is_statement ? TypeManager.void_type : type;
 404                                 Parameter[] p = new Parameter [dyn_args_count + 1];
 405                                 p[0] = new Parameter (targs [0], "p0", Parameter.Modifier.NONE, null, loc);
 406
 407                                 for (int i = 1; i < dyn_args_count + 1; ++i)
 408                                         p[i] = new Parameter (targs[i], "p" + i.ToString ("X"), arguments[i - 1].Modifier, null, loc);
 409
 410                                 TypeContainer parent = CreateSiteContainer ();
 411                                 Delegate d = new Delegate (parent.NamespaceEntry, parent, new TypeExpression (TypeManager.TypeToReflectionType (rt), loc),
 412                                         Modifiers.INTERNAL | Modifiers.COMPILER_GENERATED,
 413                                         new MemberName ("Container" + container_counter++.ToString ("X")),
 414                                         new ParametersCompiled (p), null);
 415
 416                                 d.DefineType ();
 417                                 d.Define ();
 418
 419                                 parent.AddDelegate (d);
 420                                 del_type = new TypeExpression (d.TypeBuilder, loc);
 421                         }
 422
 423                         TypeExpr site_type = new GenericTypeExpr (TypeManager.generic_call_site_type, new TypeArguments (del_type), loc);
 424                         return site_type;
 425                 }
 426
 427                 public static void Reset ()
 428                 {
 429                         global_site_container = null;
 430                         field_counter = container_counter = 0;
 431                 }
 432         }
 433
 434         //
 435         // Dynamic member access compound assignment for events
 436         //
 437         class DynamicEventCompoundAssign : DynamicExpressionStatement, IDynamicBinder
 438         {
 439                 string name;
 440                 Statement condition;
 441
 442                 public DynamicEventCompoundAssign (string name, Arguments args, ExpressionStatement assignment, ExpressionStatement invoke, Location loc)
 443                         : base (null, args, loc)
 444                 {
 445                         this.name = name;
 446                         base.binder = this;
 447
 448                         // Used by += or -= only
 449                         type = TypeManager.bool_type;
 450
 451                         condition = new If (
 452                                 new Binary (Binary.Operator.Equality, this, new BoolLiteral (true, loc)),
 453                                 new StatementExpression (invoke), new StatementExpression (assignment),
 454                                 loc);
 455                 }
 456
 457                 public Expression CreateCallSiteBinder (ResolveContext ec, Arguments args)
 458                 {
 459                         Arguments binder_args = new Arguments (3);
 460
 461                         binder_args.Add (new Argument (new BinderFlags (0, this)));
 462                         binder_args.Add (new Argument (new StringLiteral (name, loc)));
 463                         binder_args.Add (new Argument (new TypeOf (new TypeExpression (ec.CurrentType, loc), loc)));
 464
 465                         return new Invocation (GetBinder ("IsEvent", loc), binder_args);
 466                 }
 467
 468                 public override void EmitStatement (EmitContext ec)
 469                 {
 470                         condition.Emit (ec);
 471                 }
 472         }
 473
 474         class DynamicConversion : DynamicExpressionStatement, IDynamicBinder
 475         {
 476                 public DynamicConversion (Type targetType, CSharpBinderFlags flags, Arguments args, Location loc)
 477                         : base (null, args, loc)
 478                 {
 479                         type = targetType;
 480                         base.flags = flags;
 481                         base.binder = this;
 482                 }
 483
 484                 public Expression CreateCallSiteBinder (ResolveContext ec, Arguments args)
 485                 {
 486                         Arguments binder_args = new Arguments (2);
 487
 488                         flags |= ec.HasSet (ResolveContext.Options.CheckedScope) ? CSharpBinderFlags.CheckedContext : 0;
 489
 490                         binder_args.Add (new Argument (new BinderFlags (flags, this)));
 491                         binder_args.Add (new Argument (new TypeOf (new TypeExpression (type, loc), loc)));
 492                         return new Invocation (GetBinder ("Convert", loc), binder_args);
 493                 }
 494         }
 495
 496         class DynamicConstructorBinder : DynamicExpressionStatement, IDynamicBinder
 497         {
 498                 public DynamicConstructorBinder (Type type, Arguments args, Location loc)
 499                         : base (null, args, loc)
 500                 {
 501                         this.type = type;
 502                         base.binder = this;
 503                 }
 504
 505                 public Expression CreateCallSiteBinder (ResolveContext ec, Arguments args)
 506                 {
 507                         Arguments binder_args = new Arguments (3);
 508
 509                         binder_args.Add (new Argument (new BinderFlags (0, this)));
 510                         binder_args.Add (new Argument (new TypeOf (new TypeExpression (ec.CurrentType, loc), loc)));
 511                         binder_args.Add (new Argument (new ImplicitlyTypedArrayCreation ("[]", args.CreateDynamicBinderArguments (ec), loc)));
 512
 513                         return new Invocation (GetBinder ("InvokeConstructor", loc), binder_args);
 514                 }
 515         }
 516
 517         class DynamicIndexBinder : DynamicMemberAssignable
 518         {
 519                 public DynamicIndexBinder (Arguments args, Location loc)
 520                         : base (args, loc)
 521                 {
 522                 }
 523
 524                 protected override Expression CreateCallSiteBinder (ResolveContext ec, Arguments args, bool isSet)
 525                 {
 526                         Arguments binder_args = new Arguments (3);
 527
 528                         binder_args.Add (new Argument (new BinderFlags (0, this)));
 529                         binder_args.Add (new Argument (new TypeOf (new TypeExpression (ec.CurrentType, loc), loc)));
 530                         binder_args.Add (new Argument (new ImplicitlyTypedArrayCreation ("[]", args.CreateDynamicBinderArguments (ec), loc)));
 531
 532                         return new Invocation (GetBinder (isSet ? "SetIndex" : "GetIndex", loc), binder_args);
 533                 }
 534         }
 535
 536         class DynamicInvocation : DynamicExpressionStatement, IDynamicBinder
 537         {
 538                 ATypeNameExpression member;
 539
 540                 public DynamicInvocation (ATypeNameExpression member, Arguments args, Location loc)
 541                         : base (null, args, loc)
 542                 {
 543                         base.binder = this;
 544                         this.member = member;
 545                 }
 546
 547                 public DynamicInvocation (ATypeNameExpression member, Arguments args, Type type, Location loc)
 548                         : this (member, args, loc)
 549                 {
 550                         // When a return type is known not to be dynamic
 551                         this.type = type;
 552                 }
 553
 554                 public static DynamicInvocation CreateSpecialNameInvoke (ATypeNameExpression member, Arguments args, Location loc)
 555                 {
 556                         return new DynamicInvocation (member, args, loc) {
 557                                 flags = CSharpBinderFlags.InvokeSpecialName
 558                         };
 559                 }
 560
 561                 public Expression CreateCallSiteBinder (ResolveContext ec, Arguments args)
 562                 {
 563                         Arguments binder_args = new Arguments (member != null ? 5 : 3);
 564                         bool is_member_access = member is MemberAccess;
 565
 566                         CSharpBinderFlags call_flags;
 567                         if (!is_member_access && member is SimpleName) {
 568                                 call_flags = CSharpBinderFlags.InvokeSimpleName;
 569                                 is_member_access = true;
 570                         } else {
 571                                 call_flags = 0;
 572                         }
 573
 574                         binder_args.Add (new Argument (new BinderFlags (call_flags, this)));
 575
 576                         if (is_member_access)
 577                                 binder_args.Add (new Argument (new StringLiteral (member.Name, member.Location)));
 578
 579                         if (member != null && member.HasTypeArguments) {
 580                                 TypeArguments ta = member.TypeArguments;
 581                                 if (ta.Resolve (ec)) {
 582                                         ArrayList targs = new ArrayList (ta.Count);
 583                                         foreach (Type t in ta.Arguments)
 584                                                 targs.Add (new TypeOf (new TypeExpression (t, loc), loc));
 585
 586                                         binder_args.Add (new Argument (new ImplicitlyTypedArrayCreation ("[]", targs, loc)));
 587                                 }
 588                         } else if (is_member_access) {
 589                                 binder_args.Add (new Argument (new NullLiteral (loc)));
 590                         }
 591
 592                         binder_args.Add (new Argument (new TypeOf (new TypeExpression (ec.CurrentType, loc), loc)));
 593
 594                         Expression real_args;
 595                         if (args == null) {
 596                                 // Cannot be null because .NET trips over
 597                                 real_args = new ArrayCreation (new MemberAccess (GetBinderNamespace (loc), "CSharpArgumentInfo", loc), "[]", new ArrayList (0), loc);
 598                         } else {
 599                                 real_args = new ImplicitlyTypedArrayCreation ("[]", args.CreateDynamicBinderArguments (ec), loc);
 600                         }
 601
 602                         binder_args.Add (new Argument (real_args));
 603
 604                         return new Invocation (GetBinder (is_member_access ? "InvokeMember" : "Invoke", loc), binder_args);
 605                 }
 606
 607                 public override void EmitStatement (EmitContext ec)
 608                 {
 609                         flags |= CSharpBinderFlags.ResultDiscarded;
 610                         base.EmitStatement (ec);
 611                 }
 612         }
 613
 614         class DynamicMemberBinder : DynamicMemberAssignable
 615         {
 616                 readonly string name;
 617
 618                 public DynamicMemberBinder (string name, Arguments args, Location loc)
 619                         : base (args, loc)
 620                 {
 621                         this.name = name;
 622                 }
 623
 624                 protected override Expression CreateCallSiteBinder (ResolveContext ec, Arguments args, bool isSet)
 625                 {
 626                         Arguments binder_args = new Arguments (4);
 627
 628                         binder_args.Add (new Argument (new BinderFlags (0, this)));
 629                         binder_args.Add (new Argument (new StringLiteral (name, loc)));
 630                         binder_args.Add (new Argument (new TypeOf (new TypeExpression (ec.CurrentType, loc), loc)));
 631                         binder_args.Add (new Argument (new ImplicitlyTypedArrayCreation ("[]", args.CreateDynamicBinderArguments (ec), loc)));
 632
 633                         return new Invocation (GetBinder (isSet ? "SetMember" : "GetMember", loc), binder_args);
 634                 }
 635         }
 636
 637         //
 638         // Any member binder which can be source and target of assignment
 639         //
 640         abstract class DynamicMemberAssignable : DynamicExpressionStatement, IDynamicBinder, IAssignMethod
 641         {
 642                 Expression setter;
 643                 Arguments setter_args;
 644
 645                 protected DynamicMemberAssignable (Arguments args, Location loc)
 646                         : base (null, args, loc)
 647                 {
 648                         base.binder = this;
 649                 }
 650
 651                 public Expression CreateCallSiteBinder (ResolveContext ec, Arguments args)
 652                 {
 653                         //
 654                         // DoResolve always uses getter
 655                         //
 656                         return CreateCallSiteBinder (ec, args, false);
 657                 }
 658
 659                 protected abstract Expression CreateCallSiteBinder (ResolveContext ec, Arguments args, bool isSet);
 660
 661                 public override Expression DoResolveLValue (ResolveContext rc, Expression right_side)
 662                 {
 663                         if (right_side == EmptyExpression.OutAccess.Instance) {
 664                                 right_side.DoResolveLValue (rc, this);
 665                                 return null;
 666                         }
 667
 668                         if (DoResolveCore (rc)) {
 669                                 setter_args = new Arguments (Arguments.Count + 1);
 670                                 setter_args.AddRange (Arguments);
 671                                 setter_args.Add (new Argument (right_side));
 672                                 setter = CreateCallSiteBinder (rc, setter_args, true);
 673                         }
 674
 675                         eclass = ExprClass.Variable;
 676                         return this;
 677                 }
 678
 679                 public override void Emit (EmitContext ec)
 680                 {
 681                         // It's null for ResolveLValue used without assignment
 682                         if (binder_expr == null)
 683                                 EmitCall (ec, setter, Arguments, false);
 684                         else
 685                                 base.Emit (ec);
 686                 }
 687
 688                 public override void EmitStatement (EmitContext ec)
 689                 {
 690                         // It's null for ResolveLValue used without assignment
 691                         if (binder_expr == null)
 692                                 EmitCall (ec, setter, Arguments, true);
 693                         else
 694                                 base.EmitStatement (ec);
 695                 }
 696
 697                 #region IAssignMethod Members
 698
 699                 public void Emit (EmitContext ec, bool leave_copy)
 700                 {
 701                         throw new NotImplementedException ();
 702                 }
 703
 704                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
 705                 {
 706                         EmitCall (ec, setter, setter_args, !leave_copy);
 707                 }
 708
 709                 #endregion
 710         }
 711
 712         class DynamicUnaryConversion : DynamicExpressionStatement, IDynamicBinder
 713         {
 714                 string name;
 715
 716                 public DynamicUnaryConversion (string name, Arguments args, Location loc)
 717                         : base (null, args, loc)
 718                 {
 719                         this.name = name;
 720                         base.binder = this;
 721                         if (name == "IsTrue" || name == "IsFalse")
 722                                 type = TypeManager.bool_type;
 723                 }
 724
 725                 public Expression CreateCallSiteBinder (ResolveContext ec, Arguments args)
 726                 {
 727                         Arguments binder_args = new Arguments (3);
 728
 729                         MemberAccess sle = new MemberAccess (new MemberAccess (
 730                                 new QualifiedAliasMember (QualifiedAliasMember.GlobalAlias, "System", loc), "Linq", loc), "Expressions", loc);
 731
 732                         var flags = ec.HasSet (ResolveContext.Options.CheckedScope) ? CSharpBinderFlags.CheckedContext : 0;
 733
 734                         binder_args.Add (new Argument (new BinderFlags (flags, this)));
 735                         binder_args.Add (new Argument (new MemberAccess (new MemberAccess (sle, "ExpressionType", loc), name, loc)));
 736                         binder_args.Add (new Argument (new ImplicitlyTypedArrayCreation ("[]", args.CreateDynamicBinderArguments (ec), loc)));
 737
 738                         return new Invocation (GetBinder ("UnaryOperation", loc), binder_args);
 739                 }
 740         }
 741 }