internal override MSAst.Expression Transform(AstGenerator ag) {
if (ag.IsGenerator) {
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 ag.AddDebugInfo(AstUtils.YieldBreak(ag.GeneratorLabel), Span);
}
return ag.AddDebugInfo(
Ast.Return(
ag.ReturnLabel,
ag.TransformOrConstantNull(_expression, typeof(object))
),
Span
);
}
internal override MSAst.Expression Transform(AstGenerator ag) {
List<MSAst.Expression> statements = new List<MSAst.Expression>();
for (int i = 0; i < _names.Length; i++) {
statements.Add(
// _references[i] = PythonOps.Import(<code context>, _names[i])
ag.AddDebugInfo(
AstUtils.Assign(
_variables[i].Variable,
Ast.Call(
AstGenerator.GetHelperMethod( // helper
_asNames[i] == SymbolId.Empty ? "ImportTop" : "ImportBottom"
),
AstUtils.CodeContext(), // 1st arg - code context
Ast.Constant(_names[i].MakeString()), // 2nd arg - module name
Ast.Constant(_forceAbsolute ? 0 : -1) // 3rd arg - absolute or relative imports
)
),
_names[i].Span
)
);
}
statements.Add(Ast.Empty());
return ag.AddDebugInfo(Ast.Block(statements.ToArray()), Span);
}
internal override MSAst.Expression TransformSet(AstGenerator ag, SourceSpan span, MSAst.Expression right, Operators op) {
if (op == Operators.None) {
return ag.AddDebugInfoAndVoid(
Binders.Set(
ag.BinderState,
typeof(object),
SymbolTable.IdToString(_name),
ag.Transform(_target),
right
),
span
);
} else {
MSAst.ParameterExpression temp = ag.GetTemporary("inplace");
return ag.AddDebugInfo(
Ast.Block(
Ast.Assign(temp, ag.Transform(_target)),
SetMemberOperator(ag, right, op, temp),
Ast.Empty()
),
Span.Start,
span.End
);
}
}
internal override MSAst.Expression Transform(AstGenerator ag) {
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])
ag.AddDebugInfoAndVoid(
GlobalAllocator.Assign(
ag.Globals.GetVariable(ag, _variables[i]),
Ast.Call(
AstGenerator.GetHelperMethod( // helper
_asNames[i] == null ? "ImportTop" : "ImportBottom"
),
ag.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 ag.AddDebugInfo(Ast.Block(statements.ToReadOnlyCollection()), Span);
}
internal override MSAst.Expression Transform(AstGenerator ag) {
if (ag.InLoop) {
return ag.AddDebugInfo(MSAst.Expression.Break(ag.BreakLabel), Span);
} else {
return null;
}
}
internal override MSAst.Expression Transform(AstGenerator ag, Type type) {
MSAst.ParameterExpression list = ag.GetTemporary("list_comprehension_list", typeof(List));
// 1. Initialization code - create list and store it in the temp variable
MSAst.Expression initialize =
Ast.Assign(
list,
Ast.Call(
AstGenerator.GetHelperMethod("MakeList", Type.EmptyTypes) // method
)
);
// 2. Create body from _item: list.Append(_item)
MSAst.Expression body = ag.AddDebugInfo(
Ast.Call(
AstGenerator.GetHelperMethod("ListAddForComprehension"),
list,
ag.TransformAsObject(_item)
),
_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(ag, body);
}
return Ast.Block(
initialize,
body,
list // result
);
}
internal override MSAst.Expression Transform(AstGenerator ag) {
MSAst.Expression raiseExpression;
if (_type == null && _value == null && _traceback == null) {
raiseExpression = Ast.Call(
AstGenerator.GetHelperMethod("MakeRethrownException"),
ag.LocalContext
);
if (!ag._isEmittingFinally) {
raiseExpression = Ast.Block(
ag.UpdateLineUpdated(true),
raiseExpression
);
}
} else {
raiseExpression = Ast.Call(
AstGenerator.GetHelperMethod("MakeException"),
ag.LocalContext,
ag.TransformOrConstantNull(_type, typeof(object)),
ag.TransformOrConstantNull(_value, typeof(object)),
ag.TransformOrConstantNull(_traceback, typeof(object))
);
}
return ag.AddDebugInfo(
Ast.Throw(raiseExpression),
Span
);
}
internal override MSAst.Expression Transform(AstGenerator ag) {
MSAst.MethodCallExpression call;
if (_locals == null && _globals == null) {
// exec code
call = Ast.Call(
AstGenerator.GetHelperMethod("UnqualifiedExec"),
AstUtils.CodeContext(),
ag.TransformAsObject(_code)
);
} 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(
AstGenerator.GetHelperMethod("QualifiedExec"),
AstUtils.CodeContext(),
ag.TransformAsObject(_code),
ag.TransformAndDynamicConvert(_globals, typeof(IAttributesCollection)),
ag.TransformOrConstantNull(_locals, typeof(object))
);
}
return ag.AddDebugInfo(call, Span);
}
internal override MSAst.Expression Transform(AstGenerator ag) {
MSAst.Expression result;
if (_else != null) {
result = ag.Transform(_else);
} else {
result = Ast.Empty();
}
// Now build from the inside out
int i = _tests.Length;
while (i-- > 0) {
IfStatementTest ist = _tests[i];
result = ag.AddDebugInfo(
Ast.Condition(
ag.TransformAndDynamicConvert(ist.Test, typeof(bool)),
ag.Transform(ist.Body),
result
),
new SourceSpan(ist.Start, ist.Header)
);
}
return result;
}
internal override MSAst.Expression Transform(AstGenerator ag) {
MSAst.Expression destination = ag.TransformAsObject(_dest);
if (_expressions.Length == 0) {
MSAst.Expression result;
if (destination != null) {
result = Ast.Call(
AstGenerator.GetHelperMethod("PrintNewlineWithDest"),
ag.LocalContext,
destination
);
} else {
result = Ast.Call(
AstGenerator.GetHelperMethod("PrintNewline"),
ag.LocalContext
);
}
return ag.AddDebugInfo(result, Span);
} else {
// Create list for the individual statements
List<MSAst.Expression> statements = new List<MSAst.Expression>();
// Store destination in a temp, if we have one
if (destination != null) {
MSAst.ParameterExpression temp = ag.GetTemporary("destination");
statements.Add(
ag.MakeAssignment(temp, destination)
);
destination = temp;
}
for (int i = 0; i < _expressions.Length; i++) {
string method = (i < _expressions.Length - 1 || _trailingComma) ? "PrintComma" : "Print";
Expression current = _expressions[i];
MSAst.MethodCallExpression mce;
if (destination != null) {
mce = Ast.Call(
AstGenerator.GetHelperMethod(method + "WithDest"),
ag.LocalContext,
destination,
ag.TransformAsObject(current)
);
} else {
mce = Ast.Call(
AstGenerator.GetHelperMethod(method),
ag.LocalContext,
ag.TransformAsObject(current)
);
}
statements.Add(mce);
}
statements.Add(AstUtils.Empty());
return ag.AddDebugInfo(Ast.Block(statements.ToArray()), Span);
}
}
internal override MSAst.Expression Transform(AstGenerator ag) {
// 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(ag));
}
statements.Add(AstUtils.Empty());
return ag.AddDebugInfo(MSAst.Expression.Block(statements), Span);
}
internal override MSAst.Expression Transform(AstGenerator ag) {
if (ag.InFinally) {
return null;
} else if (ag.InLoop) {
return ag.AddDebugInfo(MSAst.Expression.Continue(ag.ContinueLabel), Span);
} else {
return null;
}
}
internal override MSAst.Expression Transform(AstGenerator ag) {
// Transform to series of individual del statements.
MSAst.Expression[] statements = new MSAst.Expression[_expressions.Length + 1];
for (int i = 0; i < _expressions.Length; i++) {
statements[i] = _expressions[i].TransformDelete(ag);
}
statements[_expressions.Length] = AstUtils.Empty();
return ag.AddDebugInfo(MSAst.Expression.Block(statements), Span);
}
internal override MSAst.Expression Transform(AstGenerator ag) {
if (ag.InFinally) {
ag.AddError("'continue' not supported inside 'finally' clause", Span);
return null;
} else if (ag.InLoop) {
return ag.AddDebugInfo(MSAst.Expression.Continue(ag.ContinueLabel), Span);
} else {
ag.AddError("'continue' not properly in loop", Span);
return null;
}
}
internal override MSAst.Expression Transform(AstGenerator ag) {
// Transform to series of individual del statements.
MSAst.Expression[] statements = new MSAst.Expression[_expressions.Length + 1];
for (int i = 0; i < _expressions.Length; i++) {
statements[i] = _expressions[i].TransformDelete(ag);
if (statements[i] == null) {
throw PythonOps.SyntaxError(string.Format("can't delete {0}", _expressions[i].NodeName), ag.Context.SourceUnit, _expressions[i].Span, 1);
}
}
statements[_expressions.Length] = MSAst.Expression.Empty();
return ag.AddDebugInfo(MSAst.Expression.Block(statements), Span);
}
internal override MSAst.Expression Transform(AstGenerator ag) {
// If debugging is off, return empty statement
if (ag.Optimize) {
return ag.AddDebugInfo(AstUtils.Empty(), Span);
}
// Transform into:
// if (_test) {
// } else {
// RaiseAssertionError(_message);
// }
return ag.AddDebugInfo(
AstUtils.Unless( // if
ag.TransformAndDynamicConvert(_test, typeof(bool)), // _test
Ast.Call( // else branch
AstGenerator.GetHelperMethod("RaiseAssertionError"),
ag.TransformOrConstantNull(_message, typeof(object))
)
),
Span
);
}
internal override MSAst.Expression Transform(AstGenerator ag) {
// Only the body is "in the loop" for the purposes of break/continue
// The "else" clause is outside
MSAst.LabelTarget breakLabel, continueLabel;
MSAst.Expression body = ag.TransformLoopBody(_body, out breakLabel, out continueLabel);
return AstUtils.While(
ag.AddDebugInfo(
ag.TransformAndDynamicConvert(_test, typeof(bool)),
Header
),
body,
ag.Transform(_else),
breakLabel,
continueLabel
);
}
internal override MSAst.Expression Transform(AstGenerator ag) {
// Only the body is "in the loop" for the purposes of break/continue
// The "else" clause is outside
MSAst.LabelTarget breakLabel, continueLabel;
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 ag.Transform(_else);
}
}
MSAst.Expression test = MSAst.Expression.Constant(true);
MSAst.Expression res = AstUtils.While(
test,
ag.TransformLoopBody(_body, SourceLocation.Invalid, out breakLabel, out continueLabel),
ag.Transform(_else),
breakLabel,
continueLabel
);
if (_test.Start.Line != _body.Start.Line) {
res = ag.AddDebugInfo(res, _test.Span);
}
return res;
}
return AstUtils.While(
ag.AddDebugInfo(
ag.TransformAndDynamicConvert(_test, typeof(bool)),
Header
),
ag.TransformLoopBody(_body, _test.Start, out breakLabel, out continueLabel),
ag.Transform(_else),
breakLabel,
continueLabel
);
}
internal override MSAst.Expression Transform(AstGenerator ag, Type type) {
// (yield z) becomes:
// .comma (1) {
// .void ( .yield_statement (_expression) ),
// $gen.CheckThrowable() // <-- has return result from send
// }
return Ast.Block(
ag.AddDebugInfo(
AstUtils.YieldReturn(
ag.GeneratorLabel,
AstUtils.Convert(ag.Transform(_expression), typeof(object))
),
Span
),
CreateCheckThrowExpression(ag, Span) // emits ($gen.CheckThrowable())
);
}
internal override MSAst.Expression Transform(AstGenerator ag) {
MSAst.MethodCallExpression raiseExpression;
if (_type == null && _value == null && _traceback == null) {
raiseExpression = Ast.Call(
AstGenerator.GetHelperMethod("MakeRethrownException"),
AstUtils.CodeContext()
);
} else {
raiseExpression = Ast.Call(
AstGenerator.GetHelperMethod("MakeException"),
AstUtils.CodeContext(),
ag.TransformOrConstantNull(_type, typeof(object)),
ag.TransformOrConstantNull(_value, typeof(object)),
ag.TransformOrConstantNull(_traceback, typeof(object))
);
}
return ag.AddDebugInfo(
Ast.Throw(raiseExpression),
Span
);
}
internal override MSAst.Expression TransformSet(AstGenerator ag, SourceSpan span, MSAst.Expression right, PythonOperationKind op) {
if (op == PythonOperationKind.None) {
return ag.AddDebugInfoAndVoid(
ag.Set(
typeof(object),
_name,
ag.Transform(_target),
right
),
span
);
} else {
MSAst.ParameterExpression temp = ag.GetTemporary("inplace");
return ag.AddDebugInfo(
Ast.Block(
Ast.Assign(temp, ag.Transform(_target)),
SetMemberOperator(ag, right, op, temp),
AstUtils.Empty()
),
Span.Start,
span.End
);
}
}
/// <summary>
/// Surrounds the body of an except block w/ the appropriate code for maintaining the traceback.
/// </summary>
private static MSAst.Expression GetTracebackHeader(SourceSpan span, AstGenerator ag, MSAst.ParameterExpression exception, MSAst.Expression body) {
// we are about to enter a except block. We need to emit the line number update so we track
// the line that the exception was thrown from. We then need to build exc_info() so that
// it's available. Finally we clear the list of dynamic stack frames because they've all
// been associated with this exception.
return ag.AddDebugInfo(
Ast.Block(
// pass false so if we take another exception we'll add it to the frame list
ag.TrackLines ? ag.GetLineNumberUpdateExpression(false) : MSAst.Expression.Empty(),
Ast.Call(
AstGenerator.GetHelperMethod("BuildExceptionInfo"),
AstUtils.CodeContext(),
exception
),
body,
Ast.Empty()
),
span
);
}
internal override MSAst.Expression Transform(AstGenerator ag) {
Debug.Assert(_variable != null, "Shouldn't be called by lamda expression");
ag.DisableInterpreter = true;
MSAst.Expression function = TransformToFunctionExpression(ag);
return ag.AddDebugInfo(AstUtils.Assign(_variable.Variable, function), new SourceSpan(Start, Header));
}
internal static MSAst.Expression TransformForStatement(AstGenerator ag, MSAst.ParameterExpression enumerator,
Expression list, Expression left, MSAst.Expression body,
Statement else_, SourceSpan span, SourceLocation header,
MSAst.LabelTarget breakLabel, MSAst.LabelTarget continueLabel) {
// enumerator = PythonOps.GetEnumeratorForIteration(list)
MSAst.Expression init = Ast.Assign(
enumerator,
ag.Operation(
typeof(IEnumerator),
PythonOperationKind.GetEnumeratorForIteration,
ag.TransformAsObject(list)
)
);
// while enumerator.MoveNext():
// left = enumerator.Current
// body
// else:
// else
MSAst.Expression ls = AstUtils.Loop(
ag.AddDebugInfo(Ast.Call(
enumerator,
typeof(IEnumerator).GetMethod("MoveNext")
), left.Span),
null,
Ast.Block(
left.TransformSet(
ag,
SourceSpan.None,
Ast.Call(
enumerator,
typeof(IEnumerator).GetProperty("Current").GetGetMethod()
),
PythonOperationKind.None
),
body,
ag.UpdateLineNumber(list.Start.Line),
AstUtils.Empty()
),
ag.Transform(else_),
breakLabel,
continueLabel
);
return Ast.Block(
init,
ls,
AstUtils.Empty()
);
}
internal override MSAst.Expression Transform(AstGenerator ag) {
// allocated all variables here so they won't be shared w/ other
// locals allocated during the body or except blocks.
MSAst.ParameterExpression noNestedException = null;
if (_finally != null) {
noNestedException = ag.GetTemporary("$noException", typeof(bool));
}
MSAst.ParameterExpression lineUpdated = null;
MSAst.ParameterExpression runElse = null;
if (_else != null || (_handlers != null && _handlers.Length > 0)) {
lineUpdated = ag.GetTemporary("$lineUpdated", typeof(bool));
if (_else != null) {
runElse = ag.GetTemporary("run_else", typeof(bool));
}
}
// don't allocate locals below here...
MSAst.Expression body = ag.Transform(_body);
MSAst.Expression @else = ag.Transform(_else);
if (body == null) {
return null;
}
MSAst.ParameterExpression exception;
MSAst.Expression @catch = TransformHandlers(ag, out exception);
MSAst.Expression result;
// 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, Ast.Constant(true)),
// save existing line updated, we could choose to do this only for nested exception handlers.
ag.PushLineUpdated(false, lineUpdated),
AstUtils.Try(
ag.AddDebugInfo(Ast.Empty(), new SourceSpan(Span.Start, _header)),
body
).Catch(exception,
Ast.Assign(runElse, Ast.Constant(false)),
@catch,
// restore existing line updated after exception handler completes
ag.PopLineUpdated(lineUpdated),
Ast.Default(body.Type)
),
AstUtils.IfThen(runElse,
@else
),
Ast.Empty()
);
} else if (@catch != null) { // no "else" clause
// try {
// <try body>
// } catch (Exception e) {
// ... catch handling ...
// }
//
result = AstUtils.Try(
ag.AddDebugInfo(Ast.Empty(), new SourceSpan(Span.Start, _header)),
// save existing line updated
ag.PushLineUpdated(false, lineUpdated),
body
).Catch(exception,
@catch,
// restore existing line updated after exception handler completes
ag.PopLineUpdated(lineUpdated),
Ast.Default(body.Type)
);
} else {
result = body;
}
try {
return AddFinally(ag, result, noNestedException);
} finally {
// free all locals here after the children nodes have been generated
if (lineUpdated != null) {
ag.FreeTemp(lineUpdated);
}
if (runElse != null) {
ag.FreeTemp(@runElse);
}
}
}
internal MSAst.Expression TransformToFunctionExpression(AstGenerator ag) {
string name;
if (IsLambda) {
name = "<lambda$" + Interlocked.Increment(ref _lambdaId) + ">";
} else {
name = SymbolTable.IdToString(_name);
}
// Create AST generator to generate the body with
AstGenerator bodyGen = new AstGenerator(ag, name, IsGenerator, false);
bodyGen.DisableInterpreter = true;
// Transform the parameters.
// Populate the list of the parameter names and defaults.
List<MSAst.Expression> defaults = new List<MSAst.Expression>(0);
List<MSAst.Expression> names = new List<MSAst.Expression>();
TransformParameters(ag, bodyGen, defaults, names);
List<MSAst.Expression> statements = new List<MSAst.Expression>();
// Create variables and references. Since references refer to
// parameters, do this after parameters have been created.
CreateVariables(bodyGen, statements);
// Initialize parameters - unpack tuples.
// Since tuples unpack into locals, this must be done after locals have been created.
InitializeParameters(bodyGen, statements);
// For generators, we need to do a check before the first statement for Generator.Throw() / Generator.Close().
// The exception traceback needs to come from the generator's method body, and so we must do the check and throw
// from inside the generator.
if (IsGenerator) {
MSAst.Expression s1 = YieldExpression.CreateCheckThrowExpression(bodyGen, SourceSpan.None);
statements.Add(s1);
}
MSAst.ParameterExpression extracted = null;
if (!IsGenerator && _canSetSysExcInfo) {
// need to allocate the exception here so we don't share w/ exceptions made & freed
// during the body.
extracted = bodyGen.GetTemporary("$ex", typeof(Exception));
}
// Transform the body and add the resulting statements into the list
TransformBody(bodyGen, statements);
if (ag.DebugMode) {
// add beginning and ending break points for the function.
if (GetExpressionEnd(statements[statements.Count - 1]) != Body.End) {
statements.Add(ag.AddDebugInfo(Ast.Empty(), new SourceSpan(Body.End, Body.End)));
}
}
MSAst.Expression body = Ast.Block(new ReadOnlyCollection<MSAst.Expression>(statements.ToArray()));
// 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(
AstGenerator.GetHelperMethod("SaveCurrentException")
)
),
body
).Finally(
Ast.Call(
AstGenerator.GetHelperMethod("RestoreCurrentException"), extracted
)
);
body = s;
}
body = bodyGen.WrapScopeStatements(body);
bodyGen.Block.Body = bodyGen.AddReturnTarget(body);
FunctionAttributes flags = ComputeFlags(_parameters);
bool needsWrapperMethod = flags != FunctionAttributes.None;
if (_canSetSysExcInfo) {
flags |= FunctionAttributes.CanSetSysExcInfo;
}
MSAst.Expression code;
if (IsGenerator) {
code = bodyGen.Block.MakeGenerator(bodyGen.GeneratorLabel, GetGeneratorDelegateType(_parameters, needsWrapperMethod));
flags |= FunctionAttributes.Generator;
} else {
code = bodyGen.Block.MakeLambda(GetDelegateType(_parameters, needsWrapperMethod));
}
MSAst.Expression ret = Ast.Call(
null, // instance
typeof(PythonOps).GetMethod("MakeFunction"), // method
new ReadOnlyCollection<MSAst.Expression>(
new [] {
AstUtils.CodeContext(), // 1. Emit CodeContext
Ast.Constant(name), // 2. FunctionName
code, // 3. delegate
names.Count == 0 ? // 4. parameter names
Ast.Constant(null, typeof(string[])) :
(MSAst.Expression)Ast.NewArrayInit(typeof(string), names),
defaults.Count == 0 ? // 5. default values
Ast.Constant(null, typeof(object[])) :
(MSAst.Expression)Ast.NewArrayInit(typeof(object), defaults),
Ast.Constant(flags), // 6. flags
Ast.Constant(ag.GetDocumentation(_body), typeof(string)), // 7. doc string or null
Ast.Constant(this.Start.Line), // 8. line number
Ast.Constant(_sourceUnit.Path, typeof(string)) // 9. filename
}
)
);
ret = ag.AddDecorators(ret, _decorators);
return ret;
}
internal override MSAst.Expression TransformDelete(AstGenerator ag) {
MSAst.Expression[] statements = new MSAst.Expression[_items.Length + 1];
for (int i = 0; i < _items.Length; i++) {
statements[i] = _items[i].TransformDelete(ag);
}
statements[_items.Length] = AstUtils.Empty();
return ag.AddDebugInfo(Ast.Block(statements), Span);
}
internal override MSAst.Expression Transform(AstGenerator ag) {
if (_names == _star) {
// from a[.b] import *
return ag.AddDebugInfo(
Ast.Call(
AstGenerator.GetHelperMethod("ImportStar"),
AstUtils.CodeContext(),
Ast.Constant(_root.MakeString()),
Ast.Constant(GetLevel())
),
Span
);
} else {
// from a[.b] import x [as xx], [ y [ as yy] ] [ , ... ]
List<MSAst.Expression> statements = new List<MSAst.Expression>();
MSAst.ParameterExpression module = ag.GetTemporary("module");
// Create initializer of the array of names being passed to ImportWithNames
MSAst.ConstantExpression[] names = new MSAst.ConstantExpression[_names.Length];
for (int i = 0; i < names.Length; i++) {
names[i] = Ast.Constant(SymbolTable.IdToString(_names[i]));
}
// module = PythonOps.ImportWithNames(<context>, _root, make_array(_names))
statements.Add(
ag.AddDebugInfo(
AstUtils.Assign(
module,
Ast.Call(
AstGenerator.GetHelperMethod("ImportWithNames"),
AstUtils.CodeContext(),
Ast.Constant(_root.MakeString()),
Ast.NewArrayInit(typeof(string), names),
Ast.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(
ag.AddDebugInfo(
AstUtils.Assign(
_variables[i].Variable,
Ast.Call(
AstGenerator.GetHelperMethod("ImportFrom"),
AstUtils.CodeContext(),
module,
names[i]
)
),
Span
)
);
}
statements.Add(Ast.Empty());
return ag.AddDebugInfo(Ast.Block(statements.ToArray()), Span);
}
}
internal override MSAst.Expression TransformSet(AstGenerator ag, 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 = ag.GetTemporary("unpacking");
// 2. Add the assignment "right_temp = right" into the suite/block
MSAst.Expression assignStmt1 = AstGenerator.MakeAssignment(right_temp, right);
// 3. Call GetEnumeratorValues on the right side (stored in temp)
MSAst.Expression enumeratorValues = Ast.Call(
AstGenerator.GetHelperMethod("GetEnumeratorValues"), // method
// arguments
ag.LocalContext,
right_temp,
AstUtils.Constant(_items.Length)
);
// 4. Create temporary variable for the array
MSAst.ParameterExpression array_temp = ag.GetTemporary("array", typeof(object[]));
// 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 = ag.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(
ag,
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 = ag.AddDebugInfo(Ast.Block(sets.ToReadOnlyCollection()), leftSpan);
// 10. Free the temps
ag.FreeTemp(array_temp);
ag.FreeTemp(right_temp);
// 11. Return the suite statement (block)
return ag.AddDebugInfo(Ast.Block(assignStmt1, assignStmt2, itemSet, AstUtils.Empty()), totalSpan);
}
internal override MSAst.Expression Transform(AstGenerator ag) {
string className = SymbolTable.IdToString(_name);
AstGenerator builder = new AstGenerator(ag, className, false, "class " + className);
// we always need to create a nested context for class defs
builder.CreateNestedContext();
List<MSAst.Expression> init = new List<MSAst.Expression>();
CreateVariables(builder, init);
// Create the body
MSAst.Expression bodyStmt = builder.Transform(_body);
MSAst.Expression modStmt = ag.Globals.Assign(ag.Globals.GetVariable(_modVariable), ag.Globals.GetVariable(_modNameVariable));
string doc = ag.GetDocumentation(_body);
if (doc != null) {
init.Add(
ag.Globals.Assign(
ag.Globals.GetVariable(_docVariable),
AstUtils.Constant(doc)
)
);
}
bodyStmt = builder.WrapScopeStatements(
Ast.Block(
init.Count == 0 ?
AstGenerator.EmptyBlock :
Ast.Block(new ReadOnlyCollection<MSAst.Expression>(init)),
modStmt,
bodyStmt,
builder.LocalContext // return value
)
);
MSAst.LambdaExpression lambda = Ast.Lambda(
typeof(Func<CodeContext>),
builder.MakeBody(bodyStmt, true, false),
builder.Name + "$" + _classId++,
builder.Parameters
);
MSAst.Expression classDef = Ast.Call(
AstGenerator.GetHelperMethod("MakeClass"),
lambda,
ag.LocalContext,
AstUtils.Constant(SymbolTable.IdToString(_name)),
Ast.NewArrayInit(
typeof(object),
ag.TransformAndConvert(_bases, typeof(object))
),
AstUtils.Constant(FindSelfNames())
);
classDef = ag.AddDecorators(classDef, _decorators);
return ag.AddDebugInfo(ag.Globals.Assign(ag.Globals.GetVariable(_variable), classDef), new SourceSpan(Start, Header));
}