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public static Infinite ( System.Linq.Expressions @break, System.Linq.Expressions @continue ) : |
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| @break | System.Linq.Expressions | |
| @continue | System.Linq.Expressions | |
| return | ||
internal static MSA.Expression /*!*/ MakeCallWithBlockRetryable(AstGenerator /*!*/ gen, MSA.Expression /*!*/ invoke,
MSA.Expression blockArgVariable, MSA.Expression transformedBlock, bool isBlockDefinition)
{
Assert.NotNull(invoke);
Debug.Assert((blockArgVariable == null) == (transformedBlock == null));
// see Ruby Language.doc/Control Flow Implementation/Method Call With a Block
MSA.Expression resultVariable = gen.CurrentScope.DefineHiddenVariable("#method-result", typeof(object));
MSA.ParameterExpression evalUnwinder = gen.CurrentScope.DefineHiddenVariable("#unwinder", typeof(EvalUnwinder));
MSA.LabelTarget label = Ast.Label();
return(AstFactory.Block(
Ast.Assign(blockArgVariable, Ast.Convert(transformedBlock, blockArgVariable.Type)),
AstFactory.Infinite(label, null,
(!isBlockDefinition) ?
(MSA.Expression)Ast.Empty() :
(MSA.Expression)Methods.InitializeBlock.OpCall(blockArgVariable),
AstUtils.Try(
Ast.Assign(resultVariable, invoke)
).Catch(evalUnwinder,
Ast.Assign(
resultVariable,
Ast.Field(evalUnwinder, EvalUnwinder.ReturnValueField)
)
),
// if result != RetrySingleton then break end
AstUtils.Unless(Methods.IsRetrySingleton.OpCall(AstFactory.Box(resultVariable)), Ast.Break(label)),
// if blockParam == #block then retry end
(gen.CurrentMethod.IsTopLevelCode) ? Ast.Empty() :
AstUtils.IfThen(Ast.Equal(gen.MakeMethodBlockParameterRead(), blockArgVariable), RetryStatement.TransformRetry(gen))
),
resultVariable
));
}
internal override MSA.Expression /*!*/ Transform(AstGenerator /*!*/ gen)
{
MSA.Expression parentScope = gen.CurrentScopeVariable;
ScopeBuilder scope = new ScopeBuilder();
// define hidden parameters and RHS-placeholders (#1..#n will be used as RHS of a parallel assignment):
MSA.Expression blockParameter, selfParameter;
MSA.ParameterExpression[] parameters = DefineParameters(out selfParameter, out blockParameter);
MSA.Expression scopeVariable = scope.DefineHiddenVariable("#scope", typeof(RubyBlockScope));
MSA.LabelTarget redoLabel = Ast.Label();
gen.EnterBlockDefinition(
scope,
blockParameter,
selfParameter,
scopeVariable,
redoLabel
);
if (_definedScope != null)
{
_definedScope.TransformLocals(scope);
}
MSA.Expression paramInit = MakeParametersInitialization(gen, parameters);
MSA.ParameterExpression blockUnwinder = scope.DefineHiddenVariable("#unwinder", typeof(BlockUnwinder));
MSA.Expression loop = AstFactory.Infinite(null, redoLabel,
AstUtils.Try(
gen.TransformStatements(_body, ResultOperation.Return)
).Catch(blockUnwinder,
// redo:
AstUtils.IfThen(Ast.Field(blockUnwinder, BlockUnwinder.IsRedoField), Ast.Continue(redoLabel)),
// next:
gen.Return(Ast.Field(blockUnwinder, BlockUnwinder.ReturnValueField))
)
);
if (gen.TraceEnabled)
{
int firstStatementLine = _body.Count > 0 ? _body[0].Location.Start.Line : Location.End.Line;
int lastStatementLine = _body.Count > 0 ? _body[_body.Count - 1].Location.End.Line : Location.End.Line;
loop = Ast.TryFinally(
Ast.Block(
Methods.TraceBlockCall.OpCall(scopeVariable, blockParameter, Ast.Convert(Ast.Constant(gen.SourceUnit.Path), typeof(string)), Ast.Constant(firstStatementLine)),
loop
),
Methods.TraceBlockReturn.OpCall(scopeVariable, blockParameter, Ast.Convert(Ast.Constant(gen.SourceUnit.Path), typeof(string)), Ast.Constant(lastStatementLine))
);
}
MSA.Expression body = Ast.Block(
Ast.Assign(scopeVariable,
Methods.CreateBlockScope.OpCall(scope.VisibleVariables(), parentScope, blockParameter, selfParameter)
),
paramInit,
loop,
Ast.Empty()
);
body = gen.AddReturnTarget(scope.CreateScope(body));
gen.LeaveBlockDefinition();
int parameterCount = _parameters.LeftValues.Count;
var attributes = _parameters.GetBlockSignatureAttributes();
return(Methods.DefineBlock.OpCall(
gen.CurrentScopeVariable,
gen.CurrentRfcVariable,
gen.CurrentSelfVariable,
Ast.Lambda(
BlockDispatcher.GetDelegateType(parameterCount, attributes),
body,
gen.EncodeMethodName(gen.CurrentMethod.MethodName, Location),
new ReadOnlyCollection <MSA.ParameterExpression>(parameters)
),
Ast.Constant(parameterCount),
Ast.Constant(attributes)
));
}
private MSA.Expression /*!*/ TransformExceptionHandling(AstGenerator /*!*/ gen, ResultOperation resultOperation)
{
Assert.NotNull(gen);
MSA.Expression exceptionThrownVariable = gen.CurrentScope.DefineHiddenVariable("#exception-thrown", typeof(bool));
MSA.ParameterExpression exceptionVariable = gen.CurrentScope.DefineHiddenVariable("#exception", typeof(Exception));
MSA.Expression exceptionRethrowVariable = gen.CurrentScope.DefineHiddenVariable("#exception-rethrow", typeof(bool));
MSA.Expression retryingVariable = gen.CurrentScope.DefineHiddenVariable("#retrying", typeof(bool));
MSA.ParameterExpression evalUnwinder = gen.CurrentScope.DefineHiddenVariable("#unwinder", typeof(EvalUnwinder));
MSA.Expression oldExceptionVariable = gen.CurrentScope.DefineHiddenVariable("#old-exception", typeof(Exception));
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, Ast.Constant(null))
),
Ast.Throw(oldExceptionVariable)
),
Ast.Empty()
);
}
else
{
// rethrow:
transformedEnsure = AstUtils.IfThen(
Ast.AndAlso(
exceptionRethrowVariable,
Ast.NotEqual(
Ast.Assign(oldExceptionVariable, Methods.GetCurrentException.OpCall(gen.CurrentScopeVariable)),
Ast.Constant(null, typeof(Exception)))
),
Ast.Throw(oldExceptionVariable)
);
}
if (_elseStatements != null)
{
transformedElse = gen.TransformStatements(_elseStatements, resultOperation);
}
else
{
transformedElse = Ast.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 setInRescueFlag = null, clearInRescueFlag = null;
var breakLabel = Ast.Label();
var continueLabel = Ast.Label();
// make rescue clause:
MSA.Expression transformedRescue;
if (_rescueClauses != null)
{
// outer-most EH blocks sets and clears runtime flag RuntimeFlowControl.InTryRescue:
if (gen.CurrentRescue == null)
{
setInRescueFlag = Ast.Assign(Ast.Field(gen.CurrentRfcVariable, RuntimeFlowControl.InRescueField), Ast.Constant(true));
clearInRescueFlag = Ast.Assign(Ast.Field(gen.CurrentRfcVariable, RuntimeFlowControl.InRescueField), Ast.Constant(false));
}
else
{
setInRescueFlag = clearInRescueFlag = Ast.Empty();
}
gen.EnterRescueClause(retryingVariable, breakLabel, continueLabel);
var handlers = new IfStatementTest[_rescueClauses.Count];
for (int i = 0; i < handlers.Length; i++)
{
handlers[i] = _rescueClauses[i].Transform(gen, resultOperation);
}
transformedRescue = Ast.Block(
setInRescueFlag,
AstUtils.Try(
AstUtils.If(handlers, Ast.Assign(exceptionRethrowVariable, Ast.Constant(true)))
).Filter(evalUnwinder, Ast.Equal(Ast.Field(evalUnwinder, EvalUnwinder.ReasonField), Ast.Constant(BlockReturnReason.Retry)),
Ast.Block(
Ast.Assign(retryingVariable, Ast.Constant(true)),
Ast.Continue(continueLabel),
Ast.Empty()
)
)
);
gen.LeaveRescueClause();
}
else
{
transformedRescue = Ast.Assign(exceptionRethrowVariable, Ast.Constant(true));
}
if (_elseStatements != null)
{
transformedElse = AstUtils.Unless(exceptionThrownVariable, transformedElse);
}
var result = AstFactory.Infinite(breakLabel, continueLabel,
Ast.Assign(exceptionThrownVariable, Ast.Constant(false)),
Ast.Assign(exceptionRethrowVariable, Ast.Constant(false)),
Ast.Assign(retryingVariable, Ast.Constant(false)),
AstUtils.Try(
// save exception (old_$! is not used unless there is a rescue clause):
Ast.Block(
(_rescueClauses == null) ? (MSA.Expression)Ast.Empty() :
Ast.Assign(oldExceptionVariable, Methods.GetCurrentException.OpCall(gen.CurrentScopeVariable)),
AstUtils.Try(
transformedBody
).Filter(exceptionVariable, Methods.CanRescue.OpCall(gen.CurrentRfcVariable, exceptionVariable),
Ast.Assign(exceptionThrownVariable, Ast.Constant(true)),
Methods.SetCurrentExceptionAndStackTrace.OpCall(gen.CurrentScopeVariable, exceptionVariable),
transformedRescue
).FinallyIf((_rescueClauses != null),
// restore previous exception if the current one has been handled:
AstUtils.Unless(exceptionRethrowVariable,
Methods.SetCurrentException.OpCall(gen.CurrentScopeVariable, oldExceptionVariable)
),
clearInRescueFlag
),
// unless (exception_thrown) do <else-statements> end
transformedElse,
Ast.Empty()
)
).FilterIf((_rescueClauses != null || _elseStatements != null),
exceptionVariable, Methods.CanRescue.OpCall(gen.CurrentRfcVariable, exceptionVariable),
Ast.Block(
Methods.SetCurrentExceptionAndStackTrace.OpCall(gen.CurrentScopeVariable, exceptionVariable),
Ast.Assign(exceptionRethrowVariable, Ast.Constant(true)),
Ast.Empty()
)
).Finally(
AstUtils.Unless(retryingVariable, transformedEnsure)
),
Ast.Break(breakLabel)
);
return(result);
}
// see Ruby Language.doc/Runtime/Control Flow Implementation/While-Until
internal override MSA.Expression /*!*/ TransformRead(AstGenerator /*!*/ gen)
{
MSA.Expression resultVariable = gen.CurrentScope.DefineHiddenVariable("#loop-result", typeof(object));
MSA.Expression redoVariable = gen.CurrentScope.DefineHiddenVariable("#skip-condition", typeof(bool));
MSA.ParameterExpression unwinder;
bool isInnerLoop = gen.CurrentLoop != null;
MSA.LabelTarget breakLabel = Ast.Label();
MSA.LabelTarget continueLabel = Ast.Label();
gen.EnterLoop(redoVariable, resultVariable, breakLabel, continueLabel);
MSA.Expression transformedBody = gen.TransformStatements(_statements, ResultOperation.Ignore);
MSA.Expression transformedCondition = _condition.TransformCondition(gen, true);
gen.LeaveLoop();
MSA.Expression conditionPositiveStmt, conditionNegativeStmt;
if (_isWhileLoop)
{
conditionPositiveStmt = AstUtils.Empty();
conditionNegativeStmt = Ast.Break(breakLabel);
}
else
{
conditionPositiveStmt = Ast.Break(breakLabel);
conditionNegativeStmt = AstUtils.Empty();
}
// make the loop first:
MSA.Expression loop = new AstBlock {
gen.ClearDebugInfo(),
Ast.Assign(redoVariable, AstUtils.Constant(_isPostTest)),
AstFactory.Infinite(breakLabel, continueLabel,
AstUtils.Try(
AstUtils.If(redoVariable,
Ast.Assign(redoVariable, AstUtils.Constant(false))
).ElseIf(transformedCondition,
conditionPositiveStmt
).Else(
conditionNegativeStmt
),
transformedBody,
AstUtils.Empty()
).Catch(unwinder = Ast.Parameter(typeof(BlockUnwinder), "#u"),
// redo = u.IsRedo
Ast.Assign(redoVariable, Ast.Field(unwinder, BlockUnwinder.IsRedoField)),
AstUtils.Empty()
).Filter(unwinder = Ast.Parameter(typeof(EvalUnwinder), "#u"),
Ast.Equal(Ast.Field(unwinder, EvalUnwinder.ReasonField), AstFactory.BlockReturnReasonBreak),
// result = unwinder.ReturnValue
Ast.Assign(resultVariable, Ast.Field(unwinder, EvalUnwinder.ReturnValueField)),
Ast.Break(breakLabel)
)
),
gen.ClearDebugInfo(),
AstUtils.Empty(),
};
// wrap it to try finally that updates RFC state:
if (!isInnerLoop)
{
loop = AstUtils.Try(
Methods.EnterLoop.OpCall(gen.CurrentScopeVariable),
loop
).Finally(
Methods.LeaveLoop.OpCall(gen.CurrentScopeVariable)
);
}
return(Ast.Block(loop, resultVariable));
}