internal MSA.Expression /*!*/ Transform(AstGenerator /*!*/ gen, bool isLambda) { ScopeBuilder scope = DefineLocals(gen.CurrentScope); // define hidden parameters and RHS-placeholders (#1..#n will be used as RHS of a parallel assignment): MSA.ParameterExpression blockParameter, selfParameter; var parameters = DefineParameters(out selfParameter, out blockParameter); MSA.ParameterExpression scopeVariable = scope.DefineHiddenVariable("#scope", typeof(RubyBlockScope)); MSA.LabelTarget redoLabel = Ast.Label(); gen.EnterBlockDefinition( scope, blockParameter, selfParameter, scopeVariable, redoLabel ); MSA.Expression paramInit = MakeParametersInitialization(gen, parameters); MSA.ParameterExpression blockUnwinder, filterVariable; MSA.Expression traceCall, traceReturn; if (gen.TraceEnabled) { int firstStatementLine = _body.Count > 0 ? _body.First.Location.Start.Line : Location.End.Line; int lastStatementLine = _body.Count > 0 ? _body.Last.Location.End.Line : Location.End.Line; traceCall = Methods.TraceBlockCall.OpCall(scopeVariable, blockParameter, gen.SourcePathConstant, AstUtils.Constant(firstStatementLine)); traceReturn = Methods.TraceBlockReturn.OpCall(scopeVariable, blockParameter, gen.SourcePathConstant, AstUtils.Constant(lastStatementLine)); } else { traceCall = traceReturn = Ast.Empty(); } MSA.Expression body = AstUtils.Try( paramInit, traceCall, Ast.Label(redoLabel), AstUtils.Try( gen.TransformStatements(_body, ResultOperation.Return) ).Catch(blockUnwinder = Ast.Parameter(typeof(BlockUnwinder), "#u"), // redo: AstUtils.IfThen(Ast.Field(blockUnwinder, BlockUnwinder.IsRedoField), Ast.Goto(redoLabel)), // next: gen.Return(Ast.Field(blockUnwinder, BlockUnwinder.ReturnValueField)) ) ).Filter(filterVariable = Ast.Parameter(typeof(Exception), "#e"), Methods.FilterBlockException.OpCall(scopeVariable, filterVariable) ).Finally( traceReturn, Ast.Empty() ); body = gen.AddReturnTarget( scope.CreateScope( scopeVariable, Methods.CreateBlockScope.OpCall(new AstExpressions { scope.MakeLocalsStorage(), scope.GetVariableNamesExpression(), blockParameter, selfParameter, EnterInterpretedFrameExpression.Instance }), body ) ); gen.LeaveBlockDefinition(); int parameterCount = ParameterCount; var attributes = _parameters.GetBlockSignatureAttributes(); var dispatcher = Ast.Constant( BlockDispatcher.Create(parameterCount, attributes, gen.SourcePath, Location.Start.Line), typeof(BlockDispatcher) ); return(Ast.Coalesce( (isLambda ? Methods.InstantiateLambda : Methods.InstantiateBlock).OpCall(gen.CurrentScopeVariable, gen.CurrentSelfVariable, dispatcher), (isLambda ? Methods.DefineLambda : Methods.DefineBlock).OpCall(gen.CurrentScopeVariable, gen.CurrentSelfVariable, dispatcher, BlockDispatcher.CreateLambda( body, RubyStackTraceBuilder.EncodeMethodName(gen.CurrentMethod.MethodName, gen.SourcePath, Location, gen.DebugMode), parameters, parameterCount, attributes ) ) )); }