public static Unless ( Expression test, Expression body ) : Expression | ||
test | Expression | |
body | Expression | |
리턴 | Expression |
public override MSAst.Expression Reduce() { // If debugging is off, return empty statement if (Optimize) { return(AstUtils.Empty()); } // Transform into: // if (_test) { // } else { // RaiseAssertionError(_message); // } return(GlobalParent.AddDebugInfoAndVoid( AstUtils.Unless( // if TransformAndDynamicConvert(_test, typeof(bool)), // _test Ast.Call( // else branch AstMethods.RaiseAssertionError, TransformOrConstantNull(_message, typeof(object)) ) ), Span )); }
private MSA.Expression /*!*/ TransformExceptionHandling(AstGenerator /*!*/ gen, ResultOperation resultOperation) { Assert.NotNull(gen); MSA.Expression exceptionThrownVariable = gen.CurrentScope.DefineHiddenVariable("#exception-thrown", typeof(bool)); MSA.Expression exceptionRethrowVariable = gen.CurrentScope.DefineHiddenVariable("#exception-rethrow", typeof(bool)); MSA.Expression retryingVariable = gen.CurrentScope.DefineHiddenVariable("#retrying", typeof(bool)); MSA.Expression oldExceptionVariable = gen.CurrentScope.DefineHiddenVariable("#old-exception", typeof(Exception)); MSA.ParameterExpression unwinder, exceptionVariable; MSA.Expression transformedBody; MSA.Expression transformedEnsure; MSA.Expression transformedElse; if (_ensureStatements != null) { transformedEnsure = Ast.Block( // ensure: Ast.Assign(oldExceptionVariable, Methods.GetCurrentException.OpCall(gen.CurrentScopeVariable)), gen.TransformStatements(_ensureStatements, ResultOperation.Ignore), Methods.SetCurrentException.OpCall(gen.CurrentScopeVariable, oldExceptionVariable), // rethrow: AstUtils.IfThen( Ast.AndAlso( exceptionRethrowVariable, Ast.NotEqual(oldExceptionVariable, AstUtils.Constant(null)) ), Ast.Throw(oldExceptionVariable) ) ); } else { // rethrow: transformedEnsure = AstUtils.IfThen( Ast.AndAlso( exceptionRethrowVariable, Ast.NotEqual( Ast.Assign(oldExceptionVariable, Methods.GetCurrentException.OpCall(gen.CurrentScopeVariable)), AstUtils.Constant(null, typeof(Exception))) ), Ast.Throw(oldExceptionVariable) ); } if (_elseStatements != null) { transformedElse = gen.TransformStatements(_elseStatements, resultOperation); } else { transformedElse = AstUtils.Empty(); } // body should do return, but else-clause is present => we cannot do return from the guarded statements: // (the value of the last expression in the body cannot be the last executed expression statement => we can ignore it): transformedBody = gen.TransformStatements(_statements, (_elseStatements != null) ? ResultOperation.Ignore : resultOperation); MSA.Expression enterRescue = null, leaveRescue = null; var retryLabel = Ast.Label("retry"); // make rescue clause: MSA.Expression transformedRescue; if (_rescueClauses != null) { // outer-most EH blocks sets and clears runtime flag RuntimeFlowControl.InTryRescue: if (gen.CurrentRescue == null) { enterRescue = Methods.EnterRescue.OpCall(gen.CurrentScopeVariable); leaveRescue = Methods.LeaveRescue.OpCall(gen.CurrentScopeVariable); } else { enterRescue = leaveRescue = AstUtils.Empty(); } gen.EnterRescueClause(retryingVariable, retryLabel); var handlers = new IfStatementTest[_rescueClauses.Count]; for (int i = 0; i < handlers.Length; i++) { handlers[i] = _rescueClauses[i].Transform(gen, resultOperation); } transformedRescue = AstUtils.Try( enterRescue, AstUtils.If(handlers, Ast.Assign(exceptionRethrowVariable, AstUtils.Constant(true))) ).Filter(unwinder = Ast.Parameter(typeof(EvalUnwinder), "#u"), Ast.Equal(Ast.Field(unwinder, EvalUnwinder.ReasonField), AstUtils.Constant(BlockReturnReason.Retry)), Ast.Block( Ast.Assign(retryingVariable, AstUtils.Constant(true)), Ast.Continue(retryLabel), AstUtils.Empty() ) ); gen.LeaveRescueClause(); } else { transformedRescue = Ast.Assign(exceptionRethrowVariable, AstUtils.Constant(true)); } if (_elseStatements != null) { transformedElse = AstUtils.Unless(exceptionThrownVariable, transformedElse); } var result = Ast.Block( Ast.Label(retryLabel), AstUtils.Try( Ast.Assign(exceptionThrownVariable, AstUtils.Constant(false)), Ast.Assign(exceptionRethrowVariable, AstUtils.Constant(false)), Ast.Assign(retryingVariable, AstUtils.Constant(false)), // save exception (old_$! is not used unless there is a rescue clause): (_rescueClauses == null) ? (MSA.Expression)AstUtils.Empty() : Ast.Assign(oldExceptionVariable, Methods.GetCurrentException.OpCall(gen.CurrentScopeVariable)), AstUtils.Try( Ast.Block(transformedBody, AstUtils.Empty()) ).Filter(exceptionVariable = Ast.Parameter(typeof(Exception), "#e"), Methods.CanRescue.OpCall(gen.CurrentScopeVariable, exceptionVariable), Ast.Assign(exceptionThrownVariable, AstUtils.Constant(true)), transformedRescue, AstUtils.Empty() ).FinallyIf((_rescueClauses != null), // restore previous exception if the current one has been handled: AstUtils.Unless(exceptionRethrowVariable, Methods.SetCurrentException.OpCall(gen.CurrentScopeVariable, oldExceptionVariable) ), leaveRescue ), // unless (exception_thrown) do <else-statements> end transformedElse, AstUtils.Empty() ).FilterIf((_rescueClauses != null || _elseStatements != null), exceptionVariable = Ast.Parameter(typeof(Exception), "#e"), Methods.CanRescue.OpCall(gen.CurrentScopeVariable, exceptionVariable), Ast.Assign(exceptionRethrowVariable, AstUtils.Constant(true)), AstUtils.Empty() ).FinallyWithJumps( AstUtils.Unless(retryingVariable, transformedEnsure) ) ); return(result); }