// 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 {
- bool explicit_parameters;
-
- //
- // If set, this was a lambda expression with an expression
- // argument. And if so, we have a pointer to it, so we can
- // change it if needed.
- //
- Expression lambda_expr;
-
+ 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 (AnonymousMethodExpression parent,
- GenericMethod generic, TypeContainer host,
- Parameters parameters, Block container,
- Location loc)
- : base (parent, generic, host, parameters, container, loc)
+ public LambdaExpression (Location loc)
+ : base (loc)
{
- explicit_parameters = (parameters != null && parameters.Count > 0 && parameters [0].TypeName != null);
}
- public void SetExpression (Expression expr)
+ protected override Expression CreateExpressionTree (ResolveContext ec, TypeSpec delegate_type)
{
- lambda_expr = expr;
+ if (ec.IsInProbingMode)
+ return this;
+
+ BlockContext bc = new BlockContext (ec.MemberContext, ec.CurrentBlock.Explicit, 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);
+ }
}
-
- public override Expression DoResolve (EmitContext ec)
+
+ protected override ParametersCompiled ResolveParameters (ResolveContext ec, TypeInferenceContext tic, TypeSpec delegateType)
{
- eclass = ExprClass.Value;
- type = TypeManager.anonymous_method_type;
+ 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;
- if (explicit_parameters){
+ 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.Type = d_param;
+ ilp.Resolve (null, i);
+ }
+
+ Parameters.Types = ptypes;
+ return Parameters;
+ }
+
+ protected override Expression DoResolve (ResolveContext ec)
+ {
+ //
+ // Only explicit parameters can be resolved at this point
+ //
+ if (HasExplicitParameters) {
if (!Parameters.Resolve (ec))
return null;
}
-
- // We will resolve parameters later, we do not
- // have information at this point.
-
+
+ eclass = ExprClass.Value;
+ type = InternalType.AnonymousMethod;
return this;
}
+ protected override AnonymousMethodBody CompatibleMethodFactory (TypeSpec returnType, TypeSpec delegateType, ParametersCompiled p, ToplevelBlock b)
+ {
+ return new LambdaMethod (p, b, returnType, delegateType, loc);
+ }
+
+ public override string GetSignatureForError ()
+ {
+ return "lambda expression";
+ }
+ }
+
+ public class LambdaMethod : AnonymousMethodBody
+ {
+ public LambdaMethod (ParametersCompiled parameters,
+ ToplevelBlock block, TypeSpec return_type, TypeSpec delegate_type,
+ Location loc)
+ : base (parameters, block, return_type, delegate_type, loc)
+ {
+ }
+
+ protected override void CloneTo (CloneContext clonectx, Expression target)
+ {
+ // TODO: nothing ??
+ }
+
+ public override string ContainerType {
+ get {
+ return "lambda expression";
+ }
+ }
+
+ 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)
+ {
+ return Expr.CreateExpressionTree (ec);
+ }
+
public override void Emit (EmitContext ec)
{
+ if (statement != null) {
+ statement.EmitStatement (ec);
+ ec.Emit (OpCodes.Ret);
+ return;
+ }
+
base.Emit (ec);
}
- public override bool ImplicitStandardConversionExists (Type delegate_type)
+ protected override bool DoResolve (BlockContext ec)
{
- MethodGroupExpr invoke_mg = Delegate.GetInvokeMethod (
- Host.TypeBuilder, delegate_type, loc);
- MethodInfo invoke_mb = (MethodInfo) invoke_mg.Methods [0];
- ParameterData invoke_pd = TypeManager.GetParameterData (invoke_mb);
-
- if (Parameters.Count != invoke_pd.Count)
- return false;
-
- if (explicit_parameters){
- for (int i = 0; i < Parameters.Count; ++i) {
- if (invoke_pd.ParameterType (i) != Parameters.ParameterType (i))
- return false;
- }
- } else {
-#if false
- //
- // Although the spec requires this, csc
- // allows for REF and OUT implicit parameters.
- //
- // If implicit, D has no ref or out parameters
- //
- for (int i = 0; i < Parameters.Count; ++i) {
- if (invoke_pd.ParameterModifier (i) != Parameter.Modifier.NONE)
- return false;
- }
-#endif
+ //
+ // 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 false;
+
+ return base.DoResolve (ec);
}
}
}
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