C# CSharp.BlockContext类代码示例

		public override bool Resolve (BlockContext ec)
		{
			expr = expr.Resolve (ec);
			if (expr == null)
				return false;

			Report.Debug (64, "RESOLVE YIELD #1", this, ec, expr, expr.GetType (),
				      ec.CurrentAnonymousMethod, ec.CurrentIterator);

			if (!CheckContext (ec, loc))
				return false;

			iterator = ec.CurrentIterator;
			if (expr.Type != iterator.OriginalIteratorType) {
				expr = Convert.ImplicitConversionRequired (
					ec, expr, iterator.OriginalIteratorType, loc);
				if (expr == null)
					return false;
			}

			if (!ec.CurrentBranching.CurrentUsageVector.IsUnreachable)
				unwind_protect = ec.CurrentBranching.AddResumePoint (this, loc, out resume_pc);

			return true;
		}

		protected override Expression CreateExpressionTree (ResolveContext ec, Type delegate_type)
		{
			if (ec.IsInProbingMode)
				return this;

			BlockContext bc = new BlockContext (ec.MemberContext, ec.CurrentBlock.Explicit, TypeManager.void_type);
			Expression args = Parameters.CreateExpressionTree (bc, loc);
			Expression expr = Block.CreateExpressionTree (ec);
			if (expr == null)
				return null;

			Arguments arguments = new Arguments (2);
			arguments.Add (new Argument (expr));
			arguments.Add (new Argument (args));
			return CreateExpressionFactoryCall (ec, "Lambda",
				new TypeArguments (new TypeExpression (delegate_type, loc)),
				arguments);
		}

        protected override bool DoResolve(BlockContext ec)
        {
            //
            // When delegate returns void, only expression statements can be used
            //
            if (ec.ReturnType == TypeManager.void_type) {
                Expr = Expr.Resolve (ec);
                if (Expr == null)
                    return false;

                statement = Expr as ExpressionStatement;
                if (statement == null)
                    Expr.Error_InvalidExpressionStatement (ec);

                return true;
            }

            return base.DoResolve (ec);
        }

		/// <summary>
		///   We already know that the statement is unreachable, but we still
		///   need to resolve it to catch errors.
		/// </summary>
		public virtual bool ResolveUnreachable (BlockContext ec, bool warn)
		{
			//
			// This conflicts with csc's way of doing this, but IMHO it's
			// the right thing to do.
			//
			// If something is unreachable, we still check whether it's
			// correct.  This means that you cannot use unassigned variables
			// in unreachable code, for instance.
			//

			if (warn)
				ec.Report.Warning (162, 2, loc, "Unreachable code detected");

			ec.StartFlowBranching (FlowBranching.BranchingType.Block, loc);
			bool ok = Resolve (ec);
			ec.KillFlowBranching ();

			return ok;
		}

		protected override Expression CreateExpressionTree (ResolveContext ec, TypeSpec delegate_type)
		{
			if (ec.IsInProbingMode)
				return this;

			BlockContext bc = new BlockContext (ec.MemberContext, ec.ConstructorBlock, ec.BuiltinTypes.Void) {
				CurrentAnonymousMethod = ec.CurrentAnonymousMethod
			};

			Expression args = Parameters.CreateExpressionTree (bc, loc);
			Expression expr = Block.CreateExpressionTree (ec);
			if (expr == null)
				return null;

			Arguments arguments = new Arguments (2);
			arguments.Add (new Argument (expr));
			arguments.Add (new Argument (args));
			return CreateExpressionFactoryCall (ec, "Lambda",
				new TypeArguments (new TypeExpression (delegate_type, loc)),
				arguments);
		}

			public FieldInitializerContext (IMemberContext mc, BlockContext constructorContext)
				: base (mc, null, constructorContext.ReturnType)
			{
				flags |= Options.FieldInitializerScope | Options.ConstructorScope;
				this.ctor_block = constructorContext.CurrentBlock.Explicit;
			}

		public string [] GetCompletions (string input, out string prefix)
		{
			prefix = "";
			if (input == null || input.Length == 0)
				return null;
			
			lock (evaluator_lock){
				if (!inited)
					Init ();
				
				bool partial_input;
				CSharpParser parser = ParseString (ParseMode.GetCompletions, input, out partial_input);
				if (parser == null){
					return null;
				}
				
				Class parser_result = parser.InteractiveResult;

#if NET_4_0
				var access = AssemblyBuilderAccess.RunAndCollect;
#else
				var access = AssemblyBuilderAccess.Run;
#endif
				var a = new AssemblyDefinitionDynamic (module, "completions");
				a.Create (AppDomain.CurrentDomain, access);
				module.SetDeclaringAssembly (a);

				// Need to setup MemberCache
				parser_result.CreateContainer ();

				var method = parser_result.Members[0] as Method;
				BlockContext bc = new BlockContext (method, method.Block, ctx.BuiltinTypes.Void);

				try {
					method.Block.Resolve (null, bc, method);
				} catch (CompletionResult cr) {
					prefix = cr.BaseText;
					return cr.Result;
				} 
			}
			return null;
		}

		public static string [] GetCompletions (string input, out string prefix)
		{
			prefix = "";
			if (input == null || input.Length == 0)
				return null;
			
			lock (evaluator_lock){
				if (!inited)
					Init ();
				
				bool partial_input;
				CSharpParser parser = ParseString (ParseMode.GetCompletions, input, out partial_input);
				if (parser == null){
					if (CSharpParser.yacc_verbose_flag != 0)
						Console.WriteLine ("DEBUG: No completions available");
					return null;
				}
				
				Class parser_result = parser.InteractiveResult;

				try {
					var a = new AssemblyDefinitionDynamic (RootContext.ToplevelTypes, "temp");
					a.Create (AppDomain.CurrentDomain, AssemblyBuilderAccess.Run);
					RootContext.ToplevelTypes.SetDeclaringAssembly (a);
					RootContext.ToplevelTypes.CreateType ();
					RootContext.ToplevelTypes.Define ();

					parser_result.CreateType ();
					parser_result.Define ();
					if (ctx.Report.Errors != 0)
						return null;
					
					MethodOrOperator method = null;
					foreach (MemberCore member in parser_result.Methods){
						if (member.Name != "Host")
							continue;
						
						method = (MethodOrOperator) member;
						break;
					}
					if (method == null)
						throw new InternalErrorException ("did not find the the Host method");

					BlockContext bc = new BlockContext (method, method.Block, method.ReturnType);

					try {
						method.Block.Resolve (null, bc, method);
					} catch (CompletionResult cr){
						prefix = cr.BaseText;
						return cr.Result;
					} 
				} finally {
					parser.undo.ExecuteUndo ();
				}
				
			}
			return null;
		}

        protected void EmitCall(EmitContext ec, Expression binder, Arguments arguments, bool isStatement)
        {
            int dyn_args_count = arguments == null ? 0 : arguments.Count;
            TypeExpr site_type = CreateSiteType (RootContext.ToplevelTypes.Compiler, arguments, dyn_args_count, isStatement);
            FieldExpr site_field_expr = new FieldExpr (CreateSiteField (site_type), loc);

            SymbolWriter.OpenCompilerGeneratedBlock (ec);

            Arguments args = new Arguments (1);
            args.Add (new Argument (binder));
            StatementExpression s = new StatementExpression (new SimpleAssign (site_field_expr, new Invocation (new MemberAccess (site_type, "Create"), args)));

            BlockContext bc = new BlockContext (ec.MemberContext, null, TypeManager.void_type);
            if (s.Resolve (bc)) {
                Statement init = new If (new Binary (Binary.Operator.Equality, site_field_expr, new NullLiteral (loc), loc), s, loc);
                init.Emit (ec);
            }

            args = new Arguments (1 + dyn_args_count);
            args.Add (new Argument (site_field_expr));
            if (arguments != null) {
                foreach (Argument a in arguments) {
                    if (a is NamedArgument) {
                        // Name is not valid in this context
                        args.Add (new Argument (a.Expr, a.ArgType));
                        continue;
                    }

                    args.Add (a);
                }
            }

            Expression target = new DelegateInvocation (new MemberAccess (site_field_expr, "Target", loc).Resolve (bc), args, loc).Resolve (bc);
            if (target != null)
                target.Emit (ec);

            SymbolWriter.CloseCompilerGeneratedBlock (ec);
        }

		public void ResolveFieldInitializers (BlockContext ec)
		{
			Debug.Assert (!IsPartialPart);

			if (ec.IsStatic) {
				if (initialized_static_fields == null)
					return;

				bool has_complex_initializer = !ec.Module.Compiler.Settings.Optimize;
				int i;
				ExpressionStatement [] init = new ExpressionStatement [initialized_static_fields.Count];
				for (i = 0; i < initialized_static_fields.Count; ++i) {
					FieldInitializer fi = initialized_static_fields [i];
					ExpressionStatement s = fi.ResolveStatement (ec);
					if (s == null) {
						s = EmptyExpressionStatement.Instance;
					} else if (!fi.IsSideEffectFree) {
						has_complex_initializer = true;
					}

					init [i] = s;
				}

				for (i = 0; i < initialized_static_fields.Count; ++i) {
					FieldInitializer fi = initialized_static_fields [i];
					//
					// Need special check to not optimize code like this
					// static int a = b = 5;
					// static int b = 0;
					//
					if (!has_complex_initializer && fi.IsDefaultInitializer)
						continue;

					ec.AssignmentInfoOffset += fi.AssignmentOffset;
					ec.CurrentBlock.AddScopeStatement (new StatementExpression (init [i]));
				}

				return;
			}

			if (initialized_fields == null)
				return;

			for (int i = 0; i < initialized_fields.Count; ++i) {
				FieldInitializer fi = initialized_fields [i];

				//
				// Clone before resolving otherwise when field initializer is needed
				// in more than 1 constructor any resolve after the initial one would
				// only took the resolved expression which is problem for expressions
				// that generate extra expressions or code during Resolve phase
				//
				var cloned = fi.Clone (new CloneContext ());

				ExpressionStatement s = fi.ResolveStatement (ec);
				if (s == null) {
					initialized_fields [i] = new FieldInitializer (fi.Field, ErrorExpression.Instance, Location.Null);
					continue;
				}

				//
				// Field is re-initialized to its default value => removed
				//
				if (fi.IsDefaultInitializer && Kind != MemberKind.Struct && ec.Module.Compiler.Settings.Optimize)
					continue;

				ec.AssignmentInfoOffset += fi.AssignmentOffset;
				ec.CurrentBlock.AddScopeStatement (new StatementExpression (s));
				initialized_fields [i] = (FieldInitializer) cloned;
			}
		}

		public ExpressionStatement CreateExpressionTreeVariable (BlockContext ec)
		{
			if ((modFlags & Modifier.RefOutMask) != 0)
				ec.Report.Error (1951, Location, "An expression tree parameter cannot use `ref' or `out' modifier");

			expr_tree_variable = TemporaryVariableReference.Create (ResolveParameterExpressionType (ec, Location).Type, ec.CurrentBlock.ParametersBlock, Location);
			expr_tree_variable = (TemporaryVariableReference) expr_tree_variable.Resolve (ec);

			Arguments arguments = new Arguments (2);
			arguments.Add (new Argument (new TypeOf (parameter_type, Location)));
			arguments.Add (new Argument (new StringConstant (ec.BuiltinTypes, Name, Location)));
			return new SimpleAssign (ExpressionTreeVariableReference (),
				Expression.CreateExpressionFactoryCall (ec, "Parameter", null, arguments, Location));
		}

		//
		// Emits the code
		// 
		public void Emit (TypeDefinition parent)
		{
			DefineOverride (parent);

			var mc = (IMemberContext) method;

			method.ParameterInfo.ApplyAttributes (mc, MethodBuilder);

			ToplevelBlock block = method.Block;
			if (block != null) {
				BlockContext bc = new BlockContext (mc, block, method.ReturnType);
				if (block.Resolve (null, bc, method)) {
					debug_builder = member.Parent.CreateMethodSymbolEntry ();
					EmitContext ec = method.CreateEmitContext (MethodBuilder.GetILGenerator (), debug_builder);

					block.Emit (ec);
				}
			}
		}

		public AnonymousExpression Compatible (ResolveContext ec, AnonymousExpression ae)
		{
			if (block.Resolved)
				return this;

			// TODO: Implement clone
			BlockContext aec = new BlockContext (ec, block, ReturnType);
			aec.CurrentAnonymousMethod = ae;

			var am = this as AnonymousMethodBody;

			if (ec.HasSet (ResolveContext.Options.InferReturnType) && am != null) {
				am.ReturnTypeInference = new TypeInferenceContext ();
			}

			var bc = ec as BlockContext;

			if (bc != null) {
				aec.AssignmentInfoOffset = bc.AssignmentInfoOffset;
				aec.EnclosingLoop = bc.EnclosingLoop;
				aec.EnclosingLoopOrSwitch = bc.EnclosingLoopOrSwitch;
				aec.Switch = bc.Switch;
			}

			var errors = ec.Report.Errors;

			bool res = Block.Resolve (aec);

			if (res && errors == ec.Report.Errors) {
				MarkReachable (new Reachability ());

				if (!CheckReachableExit (ec.Report)) {
					return null;
				}

				if (bc != null)
					bc.AssignmentInfoOffset = aec.AssignmentInfoOffset;
			}

			if (am != null && am.ReturnTypeInference != null) {
				am.ReturnTypeInference.FixAllTypes (ec);
				ReturnType = am.ReturnTypeInference.InferredTypeArguments [0];
				am.ReturnTypeInference = null;

				//
				// If e is synchronous the inferred return type is T
				// If e is asynchronous and the body of F is either an expression classified as nothing
				// or a statement block where no return statements have expressions, the inferred return type is Task
				// If e is async and has an inferred result type T, the inferred return type is Task<T>
				//
				if (block.IsAsync && ReturnType != null) {
					ReturnType = ReturnType.Kind == MemberKind.Void ?
						ec.Module.PredefinedTypes.Task.TypeSpec :
						ec.Module.PredefinedTypes.TaskGeneric.TypeSpec.MakeGenericType (ec, new [] { ReturnType });
				}
			}

			if (res && errors != ec.Report.Errors)
				return null;

			return res ? this : null;
		}

		public Expression CreateExpressionTree (BlockContext ec, Location loc)
		{
			var initializers = new ArrayInitializer (Count, loc);
			foreach (Parameter p in FixedParameters) {
				//
				// Each parameter expression is stored to local variable
				// to save some memory when referenced later.
				//
				StatementExpression se = new StatementExpression (p.CreateExpressionTreeVariable (ec), Location.Null);
				if (se.Resolve (ec)) {
					ec.CurrentBlock.AddScopeStatement (new TemporaryVariableReference.Declarator (p.ExpressionTreeVariableReference ()));
					ec.CurrentBlock.AddScopeStatement (se);
				}
				
				initializers.Add (p.ExpressionTreeVariableReference ());
			}

			return new ArrayCreation (
				Parameter.ResolveParameterExpressionType (ec, loc),
				initializers, loc);
		}

		public static string [] GetCompletions (string input, out string prefix)
		{
			prefix = "";
			if (input == null || input.Length == 0)
				return null;
			
			lock (evaluator_lock){
				if (!inited)
					Init ();
				
				bool partial_input;
				CSharpParser parser = ParseString (ParseMode.GetCompletions, input, out partial_input);
				if (parser == null){
					if (CSharpParser.yacc_verbose_flag != 0)
						Console.WriteLine ("DEBUG: No completions available");
					return null;
				}
				
				Class parser_result = parser.InteractiveResult as Class;
				
				if (parser_result == null){
					if (CSharpParser.yacc_verbose_flag != 0)
						Console.WriteLine ("Do not know how to cope with !Class yet");
					return null;
				}

				try {
					RootContext.ResolveTree ();
					if (ctx.Report.Errors != 0)
						return null;
					
					RootContext.PopulateTypes ();
					if (ctx.Report.Errors != 0)
						return null;

					MethodOrOperator method = null;
					foreach (MemberCore member in parser_result.Methods){
						if (member.Name != "Host")
							continue;
						
						method = (MethodOrOperator) member;
						break;
					}
					if (method == null)
						throw new InternalErrorException ("did not find the the Host method");

					BlockContext bc = new BlockContext (method, method.Block, method.ReturnType);

					try {
						method.Block.Resolve (null, bc, method);
					} catch (CompletionResult cr){
						prefix = cr.BaseText;
						return cr.Result;
					} 
				} finally {
					parser.undo.ExecuteUndo ();
				}
				
			}
			return null;
		}