// lambda.cs: support for lambda expressions
//
// Authors: Miguel de Icaza (miguel@gnu.org)
+// Marek Safar (marek.safar@gmail.com)
//
-// Licensed under the terms of the GNU GPL
+// Dual licensed under the terms of the MIT X11 or GNU GPL
//
-// (C) 2007 Novell, Inc
+// Copyright 2007-2008 Novell, Inc
//
using System;
-using System.Collections;
+using System.Reflection;
+using System.Reflection.Emit;
namespace Mono.CSharp {
- public class LambdaExpression : AnonymousMethodExpression {
- Expression expression;
- Block block;
-
+ public class LambdaExpression : AnonymousMethodExpression
+ {
//
- // The parameter list can either be:
- // null: no parameters
- // arraylist of Parameter (explicitly typed parameters)
- // arraylist of strings (implicitly typed parameters)
+ // The parameters can either be:
+ // A list of Parameters (explicitly typed parameters)
+ // An ImplicitLambdaParameter
//
- public LambdaExpression (ArrayList parameter_list, object expression_or_block_body, Location l)
- : base (null, null, null, null, null, l)
+ public LambdaExpression (Location loc)
+ : base (loc)
{
- expression = expression_or_block_body as Expression;
- block = expression_or_block_body as Block;
+ }
- if (expression == null && block == null)
- throw new Exception ("Internal compiler error: only Expression or Block is allowed");
+ protected override Expression CreateExpressionTree (ResolveContext ec, TypeSpec delegate_type)
+ {
+ if (ec.IsInProbingMode)
+ return this;
- if (RootContext.Version < LanguageVersion.LINQ){
- Report.FeatureRequiresLINQ (l, "lambda expressions");
- return;
+ BlockContext bc = new BlockContext (ec.MemberContext, ec.ConstructorBlock, TypeManager.void_type) {
+ 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 override bool HasExplicitParameters {
+ get {
+ return Parameters.Count > 0 && !(Parameters.FixedParameters [0] is ImplicitLambdaParameter);
+ }
+ }
+
+ protected override ParametersCompiled ResolveParameters (ResolveContext ec, TypeInferenceContext tic, TypeSpec delegateType)
+ {
+ if (!delegateType.IsDelegate)
+ return null;
+
+ AParametersCollection d_params = Delegate.GetParameters (ec.Compiler, delegateType);
+
+ if (HasExplicitParameters) {
+ if (!VerifyExplicitParameters (ec, delegateType, d_params))
+ return null;
+
+ return Parameters;
+ }
+
+ //
+ // If L has an implicitly typed parameter list we make implicit parameters explicit
+ // Set each parameter of L is given the type of the corresponding parameter in D
+ //
+ if (!VerifyParameterCompatibility (ec, delegateType, d_params, ec.IsInProbingMode))
+ return null;
+
+ TypeSpec [] ptypes = new TypeSpec [Parameters.Count];
+ for (int i = 0; i < d_params.Count; i++) {
+ // D has no ref or out parameters
+ if ((d_params.FixedParameters [i].ModFlags & Parameter.Modifier.ISBYREF) != 0)
+ return null;
+
+ TypeSpec d_param = d_params.Types [i];
+
+ //
+ // When type inference context exists try to apply inferred type arguments
+ //
+ if (tic != null) {
+ d_param = tic.InflateGenericArgument (d_param);
+ }
+
+ ptypes [i] = d_param;
+ ImplicitLambdaParameter ilp = (ImplicitLambdaParameter) Parameters.FixedParameters [i];
+ ilp.SetParameterType (d_param);
+ ilp.Resolve (null, i);
+ }
+
+ Parameters.Types = ptypes;
+ return Parameters;
+ }
+
+ protected override AnonymousMethodBody CompatibleMethodFactory (TypeSpec returnType, TypeSpec delegateType, ParametersCompiled p, ParametersBlock b)
+ {
+ return new LambdaMethod (p, b, returnType, delegateType, loc);
+ }
+
+ protected override bool DoResolveParameters (ResolveContext rc)
+ {
+ //
+ // Only explicit parameters can be resolved at this point
+ //
+ if (HasExplicitParameters) {
+ return Parameters.Resolve (rc);
+ }
+
+ return true;
+ }
+
+ public override string GetSignatureForError ()
+ {
+ return "lambda expression";
+ }
+ }
+
+ class LambdaMethod : AnonymousMethodBody
+ {
+ public LambdaMethod (ParametersCompiled parameters,
+ ParametersBlock block, TypeSpec return_type, TypeSpec delegate_type,
+ Location loc)
+ : base (parameters, block, return_type, delegate_type, loc)
+ {
+ }
+
+ #region Properties
+
+ public override string ContainerType {
+ get {
+ return "lambda expression";
}
}
- public override Expression DoResolve (EmitContext ec)
+ #endregion
+
+ protected override void CloneTo (CloneContext clonectx, Expression target)
+ {
+ // TODO: nothing ??
+ }
+
+ public override Expression CreateExpressionTree (ResolveContext ec)
+ {
+ BlockContext bc = new BlockContext (ec.MemberContext, Block, ReturnType);
+ 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 (type, loc)),
+ arguments);
+ }
+ }
+
+ //
+ // This is a return statement that is prepended lambda expression bodies that happen
+ // to be expressions. Depending on the return type of the delegate this will behave
+ // as either { expr (); return (); } or { return expr (); }
+ //
+ public class ContextualReturn : Return
+ {
+ ExpressionStatement statement;
+
+ public ContextualReturn (Expression expr)
+ : base (expr, expr.Location)
+ {
+ }
+
+ public override Expression CreateExpressionTree (ResolveContext ec)
{
- throw new NotImplementedException ();
+ return Expr.CreateExpressionTree (ec);
}
public override void Emit (EmitContext ec)
{
- throw new NotImplementedException ();
+ if (statement != null) {
+ statement.EmitStatement (ec);
+ ec.Emit (OpCodes.Ret);
+ return;
+ }
+
+ base.Emit (ec);
+ }
+
+ 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);
}
}
}
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