public override MSAst.Expression Reduce()
{
MSAst.Expression raiseExpression;
if (_type == null && _value == null && _traceback == null)
{
raiseExpression = Ast.Call(
AstMethods.MakeRethrownException,
Parent.LocalContext
);
if (!InFinally)
{
raiseExpression = Ast.Block(
UpdateLineUpdated(true),
raiseExpression
);
}
}
else
{
raiseExpression = Ast.Call(
AstMethods.MakeException,
Parent.LocalContext,
TransformOrConstantNull(_type, typeof(object)),
TransformOrConstantNull(_value, typeof(object)),
TransformOrConstantNull(_traceback, typeof(object))
);
}
return(GlobalParent.AddDebugInfo(
Ast.Throw(raiseExpression),
Span
));
}
public override MSAst.Expression Reduce()
{
MSAst.MethodCallExpression call;
if (_locals == null && _globals == null)
{
// exec code
call = Ast.Call(
AstMethods.UnqualifiedExec,
Parent.LocalContext,
AstUtils.Convert(_code, typeof(object))
);
}
else
{
// exec code in globals [ , locals ]
// We must have globals now (locals is last and may be absent)
Debug.Assert(_globals != null);
call = Ast.Call(
AstMethods.QualifiedExec,
Parent.LocalContext,
AstUtils.Convert(_code, typeof(object)),
TransformAndDynamicConvert(_globals, typeof(PythonDictionary)),
TransformOrConstantNull(_locals, typeof(object))
);
}
return(GlobalParent.AddDebugInfo(call, Span));
}
public override MSAst.Expression Reduce()
{
if (Parent.IsGeneratorMethod)
{
if (_expression != null)
{
// Statements can't return null, so return a rethrow.
// Callers should detecet the ag.AddError and avoid trying to execute the tree,
// but if they accidentally do, use Throw instead of empty so that
// we'll get an exception.
return(Ast.Throw(
Ast.New(
typeof(InvalidOperationException).GetConstructor(Type.EmptyTypes)
)
));
}
return(GlobalParent.AddDebugInfo(AstUtils.YieldBreak(GeneratorLabel), Span));
}
return(GlobalParent.AddDebugInfo(
Ast.Return(
FunctionDefinition._returnLabel,
TransformOrConstantNull(_expression, typeof(object))
),
Span
));
}
public override MSAst.Expression Reduce()
{
ReadOnlyCollectionBuilder <MSAst.Expression> statements = new ReadOnlyCollectionBuilder <MSAst.Expression>();
for (int i = 0; i < _names.Length; i++)
{
statements.Add(
// _references[i] = PythonOps.Import(<code context>, _names[i])
GlobalParent.AddDebugInfoAndVoid(
AssignValue(
Parent.GetVariableExpression(_variables[i]),
LightExceptions.CheckAndThrow(
Expression.Call(
_asNames[i] == null ? AstMethods.ImportTop : AstMethods.ImportBottom,
Parent.LocalContext, // 1st arg - code context
AstUtils.Constant(_names[i].MakeString()), // 2nd arg - module name
AstUtils.Constant(_forceAbsolute ? 0 : -1) // 3rd arg - absolute or relative imports
)
)
),
_names[i].Span
)
);
}
statements.Add(AstUtils.Empty());
return(GlobalParent.AddDebugInfo(Ast.Block(statements.ToReadOnlyCollection()), Span));
}
internal override MSAst.Expression TransformSet(SourceSpan span, MSAst.Expression right, PythonOperationKind op)
{
if (op == PythonOperationKind.None)
{
return(GlobalParent.AddDebugInfoAndVoid(
GlobalParent.Set(
_name,
_target,
right
),
span
));
}
else
{
MSAst.ParameterExpression temp = Ast.Variable(typeof(object), "inplace");
return(GlobalParent.AddDebugInfo(
Ast.Block(
new[] { temp },
Ast.Assign(temp, _target),
SetMemberOperator(right, op, temp),
AstUtils.Empty()
),
Span.Start,
span.End
));
}
}
internal override MSAst.Expression TransformDelete()
{
MSAst.Expression[] statements = new MSAst.Expression[_items.Length + 1];
for (int i = 0; i < _items.Length; i++)
{
statements[i] = _items[i].TransformDelete();
}
statements[_items.Length] = AstUtils.Empty();
return(GlobalParent.AddDebugInfo(Ast.Block(statements), Span));
}
private MSAst.Expression ReduceWorker(bool optimizeDynamicConvert)
{
// Only the body is "in the loop" for the purposes of break/continue
// The "else" clause is outside
ConstantExpression constTest = _test as ConstantExpression;
if (constTest != null && constTest.Value is int)
{
// while 0: / while 1:
int val = (int)constTest.Value;
if (val == 0)
{
// completely optimize the loop away
if (_else == null)
{
return(MSAst.Expression.Empty());
}
else
{
return(_else);
}
}
MSAst.Expression test = MSAst.Expression.Constant(true);
MSAst.Expression res = AstUtils.While(
test,
_body,
_else,
_break,
_continue
);
if (GlobalParent.IndexToLocation(_test.StartIndex).Line != GlobalParent.IndexToLocation(_body.StartIndex).Line)
{
res = GlobalParent.AddDebugInfoAndVoid(res, _test.Span);
}
return(res);
}
return(AstUtils.While(
GlobalParent.AddDebugInfo(
optimizeDynamicConvert ?
TransformAndDynamicConvert(_test, typeof(bool)) :
GlobalParent.Convert(typeof(bool), Microsoft.Scripting.Actions.ConversionResultKind.ExplicitCast, _test),
Header
),
_body,
_else,
_break,
_continue
));
}
protected override Ast Body(MSAst.ParameterExpression res)
{
return(GlobalParent.AddDebugInfo(
Ast.Call(
AstMethods.SetAddForComprehension,
res,
AstUtils.Convert(_item, typeof(object))
),
_item.Span
));
}
public override MSAst.Expression Reduce()
{
// Transform to series of individual del statements.
ReadOnlyCollectionBuilder <MSAst.Expression> statements = new ReadOnlyCollectionBuilder <MSAst.Expression>(_expressions.Length + 1);
for (int i = 0; i < _expressions.Length; i++)
{
statements.Add(_expressions[i].TransformDelete());
}
statements.Add(AstUtils.Empty());
return(GlobalParent.AddDebugInfo(MSAst.Expression.Block(statements), Span));
}
protected override Ast Body(MSAst.ParameterExpression res)
{
return(GlobalParent.AddDebugInfo(
Ast.Call(
AstMethods.DictAddForComprehension,
res,
AstUtils.Convert(_key, typeof(object)),
AstUtils.Convert(_value, typeof(object))
),
new SourceSpan(_key.Span.Start, _value.Span.End)
));
}
public override MSAst.Expression Reduce()
{
if (Parent.IsGeneratorMethod)
{
// Reduce to a yield return with a marker of -2, this will be interpreted as a yield break with a return value
return(GlobalParent.AddDebugInfo(AstUtils.YieldReturn(GeneratorLabel, TransformOrConstantNull(Expression, typeof(object)), -2), Span));
}
return(GlobalParent.AddDebugInfo(
Ast.Return(
FunctionDefinition._returnLabel,
TransformOrConstantNull(Expression, typeof(object))
),
Span
));
}
public override MSAst.Expression Reduce()
{
MSAst.Expression raiseExpression;
if (Exception is null)
{
Debug.Assert(Cause is null);
raiseExpression = Ast.Call(
AstMethods.MakeRethrownException,
Parent.LocalContext
);
if (!InFinally)
{
raiseExpression = Ast.Block(
UpdateLineUpdated(true),
raiseExpression
);
}
}
else if (Cause is null)
{
raiseExpression = Ast.Call(
AstMethods.MakeException,
Parent.LocalContext,
TransformOrConstantNull(Exception, typeof(object))
);
}
else
{
raiseExpression = Ast.Call(
AstMethods.MakeExceptionWithCause,
Parent.LocalContext,
TransformOrConstantNull(Exception, typeof(object)),
TransformOrConstantNull(Cause, typeof(object))
);
}
return(GlobalParent.AddDebugInfo(
Ast.Throw(raiseExpression),
Span
));
}
public override MSAst.Expression Reduce()
{
MSAst.ParameterExpression list = Ast.Parameter(typeof(List), "list_comprehension_list");
// 1. Initialization code - create list and store it in the temp variable
MSAst.Expression initialize =
Ast.Assign(
list,
Ast.Call(AstMethods.MakeList)
);
// 2. Create body from _item: list.Append(_item)
MSAst.Expression body = GlobalParent.AddDebugInfo(
Ast.Call(
AstMethods.ListAddForComprehension,
list,
AstUtils.Convert(_item, typeof(object))
),
_item.Span
);
// 3. Transform all iterators in reverse order, building the true body:
int current = _iterators.Length;
while (current-- > 0)
{
ListComprehensionIterator iterator = _iterators[current];
body = iterator.Transform(body);
}
return(Ast.Block(
new[] { list },
initialize,
body,
list // result
));
}
/// <summary>
/// WithStatement is translated to the DLR AST equivalent to
/// the following Python code snippet (from with statement spec):
///
/// mgr = (EXPR)
/// exit = mgr.__exit__ # Not calling it yet
/// value = mgr.__enter__()
/// exc = True
/// try:
/// VAR = value # Only if "as VAR" is present
/// BLOCK
/// except:
/// # The exceptional case is handled here
/// exc = False
/// if not exit(*sys.exc_info()):
/// raise
/// # The exception is swallowed if exit() returns true
/// finally:
/// # The normal and non-local-goto cases are handled here
/// if exc:
/// exit(None, None, None)
///
/// </summary>
public override MSAst.Expression Reduce()
{
// Five statements in the result...
ReadOnlyCollectionBuilder <MSAst.Expression> statements = new ReadOnlyCollectionBuilder <MSAst.Expression>(6);
ReadOnlyCollectionBuilder <MSAst.ParameterExpression> variables = new ReadOnlyCollectionBuilder <MSAst.ParameterExpression>(6);
MSAst.ParameterExpression lineUpdated = Ast.Variable(typeof(bool), "$lineUpdated_with");
variables.Add(lineUpdated);
//******************************************************************
// 1. mgr = (EXPR)
//******************************************************************
MSAst.ParameterExpression manager = Ast.Variable(typeof(object), "with_manager");
variables.Add(manager);
statements.Add(
GlobalParent.AddDebugInfo(
Ast.Assign(
manager,
_contextManager
),
new SourceSpan(Start, _header)
)
);
//******************************************************************
// 2. exit = mgr.__exit__ # Not calling it yet
//******************************************************************
MSAst.ParameterExpression exit = Ast.Variable(typeof(object), "with_exit");
variables.Add(exit);
statements.Add(
MakeAssignment(
exit,
GlobalParent.Get(
"__exit__",
manager
)
)
);
//******************************************************************
// 3. value = mgr.__enter__()
//******************************************************************
MSAst.ParameterExpression value = Ast.Variable(typeof(object), "with_value");
variables.Add(value);
statements.Add(
GlobalParent.AddDebugInfoAndVoid(
MakeAssignment(
value,
Parent.Invoke(
new CallSignature(0),
Parent.LocalContext,
GlobalParent.Get(
"__enter__",
manager
)
)
),
new SourceSpan(Start, _header)
)
);
//******************************************************************
// 4. exc = True
//******************************************************************
MSAst.ParameterExpression exc = Ast.Variable(typeof(bool), "with_exc");
variables.Add(exc);
statements.Add(
MakeAssignment(
exc,
AstUtils.Constant(true)
)
);
//******************************************************************
// 5. The final try statement:
//
// try:
// VAR = value # Only if "as VAR" is present
// BLOCK
// except:
// # The exceptional case is handled here
// exc = False
// if not exit(*sys.exc_info()):
// raise
// # The exception is swallowed if exit() returns true
// finally:
// # The normal and non-local-goto cases are handled here
// if exc:
// exit(None, None, None)
//******************************************************************
MSAst.ParameterExpression exception;
MSAst.ParameterExpression nestedFrames = Ast.Variable(typeof(List <DynamicStackFrame>), "$nestedFrames");
variables.Add(nestedFrames);
statements.Add(
// try:
AstUtils.Try(
AstUtils.Try(// try statement body
PushLineUpdated(false, lineUpdated),
_var != null ?
(MSAst.Expression)Ast.Block(
// VAR = value
_var.TransformSet(SourceSpan.None, value, PythonOperationKind.None),
// BLOCK
_body,
AstUtils.Empty()
) :
// BLOCK
(MSAst.Expression)_body // except:, // try statement location
).Catch(exception = Ast.Variable(typeof(Exception), "exception"),
// Python specific exception handling code
TryStatement.GetTracebackHeader(
this,
exception,
GlobalParent.AddDebugInfoAndVoid(
Ast.Block(
// exc = False
MakeAssignment(
exc,
AstUtils.Constant(false)
),
Ast.Assign(
nestedFrames,
Ast.Call(AstMethods.GetAndClearDynamicStackFrames)
),
// if not exit(*sys.exc_info()):
// raise
AstUtils.IfThen(
GlobalParent.Convert(
typeof(bool),
ConversionResultKind.ExplicitCast,
GlobalParent.Operation(
typeof(bool),
PythonOperationKind.IsFalse,
MakeExitCall(exit, exception)
)
),
UpdateLineUpdated(true),
Ast.Call(
AstMethods.SetDynamicStackFrames,
nestedFrames
),
Ast.Throw(
Ast.Call(
AstMethods.MakeRethrowExceptionWorker,
exception
)
)
)
),
_body.Span
)
),
Ast.Call(
AstMethods.SetDynamicStackFrames,
nestedFrames
),
PopLineUpdated(lineUpdated),
Ast.Empty()
)
// finally:
).Finally(
// if exc:
// exit(None, None, None)
AstUtils.IfThen(
exc,
GlobalParent.AddDebugInfoAndVoid(
Ast.Block(
Ast.Dynamic(
GlobalParent.PyContext.Invoke(
new CallSignature(3) // signature doesn't include function
),
typeof(object),
new MSAst.Expression[] {
Parent.LocalContext,
exit,
AstUtils.Constant(null),
AstUtils.Constant(null),
AstUtils.Constant(null)
}
),
Ast.Empty()
),
_contextManager.Span
)
)
)
);
statements.Add(AstUtils.Empty());
return(Ast.Block(variables.ToReadOnlyCollection(), statements.ToReadOnlyCollection()));
}
/// <summary>
/// Creates the LambdaExpression which implements the body of the function.
///
/// The functions signature is either "object Function(PythonFunction, ...)"
/// where there is one object parameter for each user defined parameter or
/// object Function(PythonFunction, object[]) for functions which take more
/// than PythonCallTargets.MaxArgs arguments.
/// </summary>
private LightLambdaExpression CreateFunctionLambda()
{
bool needsWrapperMethod = _parameters.Length > PythonCallTargets.MaxArgs;
Type delegateType = GetDelegateType(_parameters, needsWrapperMethod, out _);
MSAst.ParameterExpression localContext = null;
ReadOnlyCollectionBuilder <MSAst.ParameterExpression> locals = new ReadOnlyCollectionBuilder <MSAst.ParameterExpression>();
if (NeedsLocalContext)
{
localContext = LocalCodeContextVariable;
locals.Add(localContext);
}
MSAst.ParameterExpression[] parameters = CreateParameters(needsWrapperMethod, locals);
List <MSAst.Expression> init = new List <MSAst.Expression>();
foreach (var param in _parameters)
{
if (GetVariableExpression(param.PythonVariable) is IPythonVariableExpression pyVar)
{
var varInit = pyVar.Create();
if (varInit != null)
{
init.Add(varInit);
}
}
}
// Transform the parameters.
init.Add(Ast.ClearDebugInfo(GlobalParent.Document));
locals.Add(PythonAst._globalContext);
init.Add(Ast.Assign(PythonAst._globalContext, new GetGlobalContextExpression(_parentContext)));
GlobalParent.PrepareScope(locals, init);
// Create variables and references. Since references refer to
// parameters, do this after parameters have been created.
CreateFunctionVariables(locals, init);
// Initialize parameters - unpack tuples.
// Since tuples unpack into locals, this must be done after locals have been created.
InitializeParameters(init, needsWrapperMethod, parameters);
List <MSAst.Expression> statements = new List <MSAst.Expression>();
// add beginning sequence point
var start = GlobalParent.IndexToLocation(StartIndex);
statements.Add(GlobalParent.AddDebugInfo(
AstUtils.Empty(),
new SourceSpan(new SourceLocation(0, start.Line, start.Column), new SourceLocation(0, start.Line, int.MaxValue))));
// For generators, we need to do a check before the first statement for Generator.Throw() / Generator.Close().
// The exception traceback needs to come from the generator's method body, and so we must do the check and throw
// from inside the generator.
if (IsGenerator)
{
MSAst.Expression s1 = YieldExpression.CreateCheckThrowExpression(SourceSpan.None);
statements.Add(s1);
}
if (Body.CanThrow && !(Body is SuiteStatement) && Body.StartIndex != -1)
{
statements.Add(UpdateLineNumber(GlobalParent.IndexToLocation(Body.StartIndex).Line));
}
statements.Add(Body);
MSAst.Expression body = Ast.Block(statements);
if (Body.CanThrow && GlobalParent.PyContext.PythonOptions.Frames)
{
body = AddFrame(LocalContext, Ast.Property(_functionParam, typeof(PythonFunction).GetProperty(nameof(PythonFunction.__code__))), body);
locals.Add(FunctionStackVariable);
}
body = AddProfiling(body);
body = WrapScopeStatements(body, Body.CanThrow);
body = Ast.Block(body, AstUtils.Empty());
body = AddReturnTarget(body);
MSAst.Expression bodyStmt = body;
if (localContext != null)
{
var createLocal = CreateLocalContext(_parentContext);
init.Add(
Ast.Assign(
localContext,
createLocal
)
);
}
init.Add(bodyStmt);
bodyStmt = Ast.Block(init);
// wrap a scope if needed
bodyStmt = Ast.Block(locals.ToReadOnlyCollection(), bodyStmt);
return(AstUtils.LightLambda(
typeof(object),
delegateType,
AddDefaultReturn(bodyStmt, typeof(object)),
Name + "$" + Interlocked.Increment(ref _lambdaId),
parameters
));
}
public override MSAst.Expression Reduce()
{
// allocated all variables here so they won't be shared w/ other
// locals allocated during the body or except blocks.
MSAst.ParameterExpression lineUpdated = null;
MSAst.ParameterExpression runElse = null;
if (_else != null || (_handlers != null && _handlers.Length > 0))
{
lineUpdated = Ast.Variable(typeof(bool), "$lineUpdated_try");
if (_else != null)
{
runElse = Ast.Variable(typeof(bool), "run_else");
}
}
// don't allocate locals below here...
MSAst.Expression body = _body;
MSAst.Expression @else = _else;
MSAst.Expression @catch, result;
MSAst.ParameterExpression exception;
if (_handlers != null && _handlers.Length > 0)
{
exception = Ast.Variable(typeof(Exception), "$exception");
@catch = TransformHandlers(exception);
}
else
{
exception = null;
@catch = null;
}
// We have else clause, must generate guard around it
if (@else != null)
{
Debug.Assert(@catch != null);
// run_else = true;
// try {
// try_body
// } catch ( ... ) {
// run_else = false;
// catch_body
// }
// if (run_else) {
// else_body
// }
result =
Ast.Block(
Ast.Assign(runElse, AstUtils.Constant(true)),
// save existing line updated, we could choose to do this only for nested exception handlers.
PushLineUpdated(false, lineUpdated),
AstUtils.Try(
Parent.AddDebugInfo(AstUtils.Empty(), new SourceSpan(Span.Start, _header)),
body
).Catch(exception,
Ast.Assign(runElse, AstUtils.Constant(false)),
@catch,
// restore existing line updated after exception handler completes
PopLineUpdated(lineUpdated),
Ast.Assign(exception, Ast.Constant(null, typeof(Exception))),
AstUtils.Default(body.Type)
),
AstUtils.IfThen(runElse,
@else
),
AstUtils.Empty()
);
}
else if (@catch != null) // no "else" clause
// try {
// <try body>
// } catch (Exception e) {
// ... catch handling ...
// }
//
{
result =
AstUtils.Try(
GlobalParent.AddDebugInfo(AstUtils.Empty(), new SourceSpan(Span.Start, _header)),
// save existing line updated
PushLineUpdated(false, lineUpdated),
body
).Catch(exception,
@catch,
// restore existing line updated after exception handler completes
PopLineUpdated(lineUpdated),
Ast.Call(AstMethods.ExceptionHandled, Parent.LocalContext),
Ast.Assign(exception, Ast.Constant(null, typeof(Exception))),
AstUtils.Default(body.Type)
);
}
else
{
result = body;
}
return(Ast.Block(
GetVariables(lineUpdated, runElse),
AddFinally(result)
));
}
/// <summary>
/// Transform multiple python except handlers for a try block into a single catch body.
/// </summary>
/// <param name="exception">The variable for the exception in the catch block.</param>
/// <returns>Null if there are no except handlers. Else the statement to go inside the catch handler</returns>
private MSAst.Expression TransformHandlers(MSAst.ParameterExpression exception)
{
Assert.NotEmpty(_handlers);
MSAst.ParameterExpression extracted = Ast.Variable(typeof(object), "$extracted");
var tests = new List <Microsoft.Scripting.Ast.IfStatementTest>(_handlers.Length);
MSAst.ParameterExpression converted = null;
MSAst.Expression catchAll = null;
for (int index = 0; index < _handlers.Length; index++)
{
TryStatementHandler tsh = _handlers[index];
if (tsh.Test != null)
{
Microsoft.Scripting.Ast.IfStatementTest ist;
// translating:
// except Test ...
//
// generate following AST for the Test (common part):
// CheckException(exception, Test)
MSAst.Expression test =
Ast.Call(
AstMethods.CheckException,
Parent.LocalContext,
extracted,
AstUtils.Convert(tsh.Test, typeof(object))
);
if (tsh.Target != null)
{
// translating:
// except Test, Target:
// <body>
// into:
// if ((converted = CheckException(exception, Test)) != null) {
// Target = converted;
// traceback-header
// <body>
// }
if (converted == null)
{
converted = Ast.Variable(typeof(object), "$converted");
}
ist = AstUtils.IfCondition(
Ast.NotEqual(
Ast.Assign(converted, test),
AstUtils.Constant(null)
),
Ast.Block(
tsh.Target.TransformSet(SourceSpan.None, converted, PythonOperationKind.None),
GlobalParent.AddDebugInfo(
GetTracebackHeader(
this,
exception,
tsh.Body
),
new SourceSpan(tsh.Start, tsh.Header)
),
AstUtils.Empty()
)
);
}
else
{
// translating:
// except Test:
// <body>
// into:
// if (CheckException(exception, Test) != null) {
// traceback-header
// <body>
// }
ist = AstUtils.IfCondition(
Ast.NotEqual(
test,
AstUtils.Constant(null)
),
GlobalParent.AddDebugInfo(
GetTracebackHeader(
this,
exception,
tsh.Body
),
new SourceSpan(tsh.Start, tsh.Header)
)
);
}
// Add the test to the if statement test cascade
tests.Add(ist);
}
else
{
Debug.Assert(index == _handlers.Length - 1);
Debug.Assert(catchAll == null);
// translating:
// except:
// <body>
// into:
// {
// traceback-header
// <body>
// }
catchAll = GlobalParent.AddDebugInfo(
GetTracebackHeader(this, exception, tsh.Body),
new SourceSpan(tsh.Start, tsh.Header)
);
}
}
MSAst.Expression body = null;
if (tests.Count > 0)
{
// rethrow the exception if we have no catch-all block
if (catchAll == null)
{
catchAll = Ast.Block(
Parent.GetSaveLineNumberExpression(exception, true),
Ast.Throw(
Ast.Call(
typeof(ExceptionHelpers).GetMethod("UpdateForRethrow"),
exception
)
)
);
}
body = AstUtils.If(
tests.ToArray(),
catchAll
);
}
else
{
Debug.Assert(catchAll != null);
body = catchAll;
}
IList <MSAst.ParameterExpression> args;
if (converted != null)
{
args = new ReadOnlyCollectionBuilder <MSAst.ParameterExpression> {
converted, extracted
};
}
else
{
args = new ReadOnlyCollectionBuilder <MSAst.ParameterExpression> {
extracted
};
}
// Codegen becomes:
// extracted = PythonOps.SetCurrentException(exception)
// < dynamic exception analysis >
return(Ast.Block(
args,
Ast.Assign(
extracted,
Ast.Call(
AstMethods.SetCurrentException,
Parent.LocalContext,
exception
)
),
body,
Ast.Assign(extracted, Ast.Constant(null)),
AstUtils.Empty()
));
}
internal override MSAst.Expression TransformSet(SourceSpan span, MSAst.Expression right, PythonOperationKind op)
{
// if we just have a simple named multi-assignment (e.g. a, b = 1,2)
// then go ahead and step over the entire statement at once. If we have a
// more complex statement (e.g. a.b, c.d = 1, 2) then we'll step over the
// sets individually as they could be property sets the user wants to step
// into. TODO: Enable stepping of the right hand side?
bool emitIndividualSets = false;
foreach (Expression e in _items)
{
if (IsComplexAssignment(e))
{
emitIndividualSets = true;
break;
}
}
SourceSpan rightSpan = SourceSpan.None;
SourceSpan leftSpan =
(Span.Start.IsValid && span.IsValid) ?
new SourceSpan(Span.Start, span.End) :
SourceSpan.None;
SourceSpan totalSpan = SourceSpan.None;
if (emitIndividualSets)
{
rightSpan = span;
leftSpan = SourceSpan.None;
totalSpan = (Span.Start.IsValid && span.IsValid) ?
new SourceSpan(Span.Start, span.End) :
SourceSpan.None;
}
// 1. Evaluate the expression and assign the value to the temp.
MSAst.ParameterExpression right_temp = Ast.Variable(typeof(object), "unpacking");
// 2. Add the assignment "right_temp = right" into the suite/block
MSAst.Expression assignStmt1 = MakeAssignment(right_temp, right);
// 3. Call GetEnumeratorValues on the right side (stored in temp)
MSAst.Expression enumeratorValues = Expression.Convert(LightExceptions.CheckAndThrow(
Expression.Call(
emitIndividualSets ?
AstMethods.GetEnumeratorValues :
AstMethods.GetEnumeratorValuesNoComplexSets, // method
// arguments
Parent.LocalContext,
right_temp,
AstUtils.Constant(_items.Length)
)
), typeof(object[]));
// 4. Create temporary variable for the array
MSAst.ParameterExpression array_temp = Ast.Variable(typeof(object[]), "array");
// 5. Assign the value of the method call (mce) into the array temp
// And add the assignment "array_temp = Ops.GetEnumeratorValues(...)" into the block
MSAst.Expression assignStmt2 = MakeAssignment(
array_temp,
enumeratorValues,
rightSpan
);
ReadOnlyCollectionBuilder <MSAst.Expression> sets = new ReadOnlyCollectionBuilder <MSAst.Expression>(_items.Length + 1);
for (int i = 0; i < _items.Length; i++)
{
// target = array_temp[i]
Expression target = _items[i];
if (target == null)
{
continue;
}
// 6. array_temp[i]
MSAst.Expression element = Ast.ArrayAccess(
array_temp, // array expression
AstUtils.Constant(i) // index
);
// 7. target = array_temp[i], and add the transformed assignment into the list of sets
MSAst.Expression set = target.TransformSet(
emitIndividualSets ? // span
target.Span :
SourceSpan.None,
element,
PythonOperationKind.None
);
sets.Add(set);
}
// 9. add the sets as their own block so they can be marked as a single span, if necessary.
sets.Add(AstUtils.Empty());
MSAst.Expression itemSet = GlobalParent.AddDebugInfo(Ast.Block(sets.ToReadOnlyCollection()), leftSpan);
// 10. Return the suite statement (block)
return(GlobalParent.AddDebugInfo(Ast.Block(new[] { array_temp, right_temp }, assignStmt1, assignStmt2, itemSet, AstUtils.Empty()), totalSpan));
}
public override MSAst.Expression Reduce()
{
MSAst.Expression destination = _dest;
if (_expressions.Length == 0)
{
MSAst.Expression result;
if (destination != null)
{
result = Ast.Call(
AstMethods.PrintNewlineWithDest,
Parent.LocalContext,
destination
);
}
else
{
result = Ast.Call(
AstMethods.PrintNewline,
Parent.LocalContext
);
}
return(GlobalParent.AddDebugInfo(result, Span));
}
else
{
// Create list for the individual statements
ReadOnlyCollectionBuilder <MSAst.Expression> statements = new ReadOnlyCollectionBuilder <MSAst.Expression>();
// Store destination in a temp, if we have one
MSAst.ParameterExpression temp = null;
if (destination != null)
{
temp = Ast.Variable(typeof(object), "destination");
statements.Add(MakeAssignment(temp, destination));
destination = temp;
}
for (int i = 0; i < _expressions.Length; i++)
{
bool withComma = (i < _expressions.Length - 1 || _trailingComma);// ? "PrintComma" : "Print";
Expression current = _expressions[i];
MSAst.MethodCallExpression mce;
if (destination != null)
{
mce = Ast.Call(
withComma ? AstMethods.PrintCommaWithDest : AstMethods.PrintWithDest,
Parent.LocalContext,
destination,
AstUtils.Convert(current, typeof(object))
);
}
else
{
mce = Ast.Call(
withComma ? AstMethods.PrintComma : AstMethods.Print,
Parent.LocalContext,
AstUtils.Convert(current, typeof(object))
);
}
statements.Add(mce);
}
statements.Add(AstUtils.Empty());
MSAst.Expression res;
if (temp != null)
{
res = Ast.Block(new[] { temp }, statements.ToReadOnlyCollection());
}
else
{
res = Ast.Block(statements.ToReadOnlyCollection());
}
return(GlobalParent.AddDebugInfo(res, Span));
}
}
/// <summary>
/// Creates the LambdaExpression which implements the body of the function.
///
/// The functions signature is either "object Function(PythonFunction, ...)"
/// where there is one object parameter for each user defined parameter or
/// object Function(PythonFunction, object[]) for functions which take more
/// than PythonCallTargets.MaxArgs arguments.
/// </summary>
private LightLambdaExpression CreateFunctionLambda()
{
bool needsWrapperMethod = _parameters.Length > PythonCallTargets.MaxArgs;
Delegate originalDelegate;
Type delegateType = GetDelegateType(_parameters, needsWrapperMethod, out originalDelegate);
MSAst.ParameterExpression localContext = null;
ReadOnlyCollectionBuilder <MSAst.ParameterExpression> locals = new ReadOnlyCollectionBuilder <MSAst.ParameterExpression>();
if (NeedsLocalContext)
{
localContext = LocalCodeContextVariable;
locals.Add(localContext);
}
MSAst.ParameterExpression[] parameters = CreateParameters(needsWrapperMethod, locals);
List <MSAst.Expression> init = new List <MSAst.Expression>();
foreach (var param in _parameters)
{
IPythonVariableExpression pyVar = GetVariableExpression(param.PythonVariable) as IPythonVariableExpression;
if (pyVar != null)
{
var varInit = pyVar.Create();
if (varInit != null)
{
init.Add(varInit);
}
}
}
// Transform the parameters.
init.Add(Ast.ClearDebugInfo(GlobalParent.Document));
locals.Add(PythonAst._globalContext);
init.Add(Ast.Assign(PythonAst._globalContext, new GetGlobalContextExpression(_parentContext)));
GlobalParent.PrepareScope(locals, init);
// Create variables and references. Since references refer to
// parameters, do this after parameters have been created.
CreateFunctionVariables(locals, init);
// If the __class__ variable is used the a class method then we need to initialize it.
// This must be done before parameter initialization (in case one of the parameters is called __class__).
ClassDefinition parent = FindParentOfType <ClassDefinition>();
PythonVariable pVar;
if (parent != null && TryGetVariable("__class__", out pVar))
{
init.Add(
AssignValue(
GetVariableExpression(pVar),
Ast.Call(AstMethods.LookupName, parent.Parent.LocalContext, Ast.Constant(parent.Name))
)
);
}
// Initialize parameters - unpack tuples.
// Since tuples unpack into locals, this must be done after locals have been created.
InitializeParameters(init, needsWrapperMethod, parameters);
List <MSAst.Expression> statements = new List <MSAst.Expression>();
// add beginning sequence point
var start = GlobalParent.IndexToLocation(StartIndex);
statements.Add(GlobalParent.AddDebugInfo(
AstUtils.Empty(),
new SourceSpan(new SourceLocation(0, start.Line, start.Column), new SourceLocation(0, start.Line, Int32.MaxValue))));
// For generators, we need to do a check before the first statement for Generator.Throw() / Generator.Close().
// The exception traceback needs to come from the generator's method body, and so we must do the check and throw
// from inside the generator.
if (IsGenerator)
{
MSAst.Expression s1 = YieldExpression.CreateCheckThrowExpression(SourceSpan.None);
statements.Add(s1);
}
MSAst.ParameterExpression extracted = null;
if (!IsGenerator && _canSetSysExcInfo)
{
// need to allocate the exception here so we don't share w/ exceptions made & freed
// during the body.
extracted = Ast.Parameter(typeof(Exception), "$ex");
locals.Add(extracted);
}
if (_body.CanThrow && !(_body is SuiteStatement) && _body.StartIndex != -1)
{
statements.Add(UpdateLineNumber(GlobalParent.IndexToLocation(_body.StartIndex).Line));
}
statements.Add(Body);
MSAst.Expression body = Ast.Block(statements);
// If this function can modify sys.exc_info() (_canSetSysExcInfo), then it must restore the result on finish.
//
// Wrap in
// $temp = PythonOps.SaveCurrentException()
// <body>
// PythonOps.RestoreCurrentException($temp)
// Skip this if we're a generator. For generators, the try finally is handled by the PythonGenerator class
// before it's invoked. This is because the restoration must occur at every place the function returns from
// a yield point. That's different than the finally semantics in a generator.
if (extracted != null)
{
MSAst.Expression s = AstUtils.Try(
Ast.Assign(
extracted,
Ast.Call(AstMethods.SaveCurrentException)
),
body
).Finally(
Ast.Call(
AstMethods.RestoreCurrentException, extracted
)
);
body = s;
}
if (_body.CanThrow && GlobalParent.PyContext.PythonOptions.Frames)
{
body = AddFrame(LocalContext, Ast.Property(_functionParam, typeof(PythonFunction).GetProperty("__code__")), body);
locals.Add(FunctionStackVariable);
}
body = AddProfiling(body);
body = WrapScopeStatements(body, _body.CanThrow);
body = Ast.Block(body, AstUtils.Empty());
body = AddReturnTarget(body);
MSAst.Expression bodyStmt = body;
if (localContext != null)
{
var createLocal = CreateLocalContext(_parentContext);
init.Add(
Ast.Assign(
localContext,
createLocal
)
);
}
init.Add(bodyStmt);
bodyStmt = Ast.Block(init);
// wrap a scope if needed
bodyStmt = Ast.Block(locals.ToReadOnlyCollection(), bodyStmt);
return(AstUtils.LightLambda(
typeof(object),
delegateType,
AddDefaultReturn(bodyStmt, typeof(object)),
Name + "$" + Interlocked.Increment(ref _lambdaId),
parameters
));
}
public override MSAst.Expression Reduce()
{
return(GlobalParent.AddDebugInfo(MSAst.Expression.Continue(_loop.ContinueLabel), Span));
}
public override MSAst.Expression Reduce()
{
if (_names == _star)
{
// from a[.b] import *
return(GlobalParent.AddDebugInfo(
Ast.Call(
AstMethods.ImportStar,
Parent.LocalContext,
AstUtils.Constant(_root.MakeString()),
AstUtils.Constant(GetLevel())
),
Span
));
}
else
{
// from a[.b] import x [as xx], [ y [ as yy] ] [ , ... ]
ReadOnlyCollectionBuilder <MSAst.Expression> statements = new ReadOnlyCollectionBuilder <MSAst.Expression>();
MSAst.ParameterExpression module = Ast.Variable(typeof(object), "module");
// Create initializer of the array of names being passed to ImportWithNames
MSAst.Expression[] names = new MSAst.Expression[_names.Length];
for (int i = 0; i < names.Length; i++)
{
names[i] = AstUtils.Constant(_names[i]);
}
// module = PythonOps.ImportWithNames(<context>, _root, make_array(_names))
statements.Add(
GlobalParent.AddDebugInfoAndVoid(
AssignValue(
module,
LightExceptions.CheckAndThrow(
Expression.Call(
AstMethods.ImportWithNames,
Parent.LocalContext,
AstUtils.Constant(_root.MakeString()),
Ast.NewArrayInit(typeof(string), names),
AstUtils.Constant(GetLevel())
)
)
),
_root.Span
)
);
// now load all the names being imported and assign the variables
for (int i = 0; i < names.Length; i++)
{
statements.Add(
GlobalParent.AddDebugInfoAndVoid(
AssignValue(
Parent.GetVariableExpression(_variables[i]),
Ast.Call(
AstMethods.ImportFrom,
Parent.LocalContext,
module,
names[i]
)
),
Span
)
);
}
statements.Add(AstUtils.Empty());
return(GlobalParent.AddDebugInfo(Ast.Block(new[] { module }, statements.ToArray()), Span));
}
}
public override MSAst.Expression Reduce()
{
return(GlobalParent.AddDebugInfo(MSAst.Expression.Break(_loop.BreakLabel), Span));
}
public override MSAst.Expression Reduce()
{
// allocated all variables here so they won't be shared w/ other
// locals allocated during the body or except blocks.
MSAst.ParameterExpression?lineUpdated = null;
MSAst.ParameterExpression?runElse = null;
MSAst.ParameterExpression?previousExceptionContext = null;
Debug.Assert(Else is null || _handlers.Length > 0);
if (_handlers.Length > 0)
{
lineUpdated = Ast.Variable(typeof(bool), "$lineUpdated_try");
if (Else != null)
{
runElse = Ast.Variable(typeof(bool), "run_else");
}
}
// don't allocate locals below here...
MSAst.Expression body = Body;
MSAst.Expression? @else = Else;
MSAst.Expression? @catch;
MSAst.Expression result;
MSAst.ParameterExpression?exception;
if (_handlers.Length > 0)
{
previousExceptionContext = Ast.Variable(typeof(Exception), "$previousException");
exception = Ast.Variable(typeof(Exception), "$exception");
@catch = TransformHandlers(exception, previousExceptionContext);
}
else if (Finally != null)
{
exception = Ast.Variable(typeof(Exception), "$exception");
@catch = null;
}
else
{
exception = null;
@catch = null;
}
// We have else clause, must generate guard around it
if (@else != null)
{
Debug.Assert(runElse != null);
Debug.Assert(previousExceptionContext != null && exception != null && @catch != null);
// run_else = true;
// try {
// try_body
// } catch ( ... ) {
// run_else = false;
// catch_body
// }
// if (run_else) {
// else_body
// }
result =
Ast.Block(
Ast.Assign(runElse, AstUtils.Constant(true)),
// save existing line updated, we could choose to do this only for nested exception handlers.
PushLineUpdated(false, lineUpdated),
LightExceptions.RewriteExternal(
AstUtils.Try(
Parent.AddDebugInfo(AstUtils.Empty(), new SourceSpan(Span.Start, GlobalParent.IndexToLocation(HeaderIndex))),
Ast.Assign(previousExceptionContext, Ast.Call(AstMethods.SaveCurrentException)),
body,
AstUtils.Constant(null)
).Catch(exception,
Ast.Assign(runElse, AstUtils.Constant(false)),
@catch,
// restore existing line updated after exception handler completes
PopLineUpdated(lineUpdated),
Ast.Assign(exception, Ast.Constant(null, typeof(Exception))),
AstUtils.Constant(null)
)
),
AstUtils.IfThen(runElse,
@else
),
AstUtils.Empty()
);
}
else if (@catch != null) // no "else" clause
// try {
// <try body>
// } catch (Exception e) {
// ... catch handling ...
// }
//
{
Debug.Assert(previousExceptionContext != null && exception != null);
result =
LightExceptions.RewriteExternal(
AstUtils.Try(
GlobalParent.AddDebugInfo(AstUtils.Empty(), new SourceSpan(Span.Start, GlobalParent.IndexToLocation(HeaderIndex))),
// save existing line updated
PushLineUpdated(false, lineUpdated),
Ast.Assign(previousExceptionContext, Ast.Call(AstMethods.SaveCurrentException)),
body,
AstUtils.Constant(null)
).Catch(exception,
@catch,
// restore existing line updated after exception handler completes
PopLineUpdated(lineUpdated),
Ast.Assign(exception, Ast.Constant(null, typeof(Exception))),
AstUtils.Constant(null)
)
);
}
else
{
result = body;
}
return(Ast.Block(
GetVariables(lineUpdated, runElse, previousExceptionContext),
AddFinally(result),
AstUtils.Default(typeof(void))
));
}