| public static Loop ( Expression test, Expression increment, Expression body, Expression @else ) : LoopExpression | ||
| test | Expression | |
| increment | Expression | |
| body | Expression | |
| @else | Expression | |
| Результат | LoopExpression | |
internal static MSAst.Expression TransformForStatement(ScopeStatement parent, MSAst.ParameterExpression enumerator,
Expression list, Expression left, MSAst.Expression body,
Statement else_, SourceSpan span, SourceLocation header,
MSAst.LabelTarget breakLabel, MSAst.LabelTarget continueLabel)
{
// enumerator, isDisposable = Dynamic(GetEnumeratorBinder, list)
MSAst.Expression init = Ast.Assign(
enumerator,
parent.GlobalParent.Operation(
typeof(KeyValuePair <IEnumerator, IDisposable>),
PythonOperationKind.GetEnumeratorForIteration,
AstUtils.Convert(list, typeof(object))
)
);
// while enumerator.MoveNext():
// left = enumerator.Current
// body
// else:
// else
MSAst.Expression ls = AstUtils.Loop(
parent.GlobalParent.AddDebugInfo(
Ast.Call(
Ast.Property(
enumerator,
typeof(KeyValuePair <IEnumerator, IDisposable>).GetProperty("Key")
),
typeof(IEnumerator).GetMethod("MoveNext")
),
left.Span
),
null,
Ast.Block(
left.TransformSet(
SourceSpan.None,
Ast.Call(
Ast.Property(
enumerator,
typeof(KeyValuePair <IEnumerator, IDisposable>).GetProperty("Key")
),
typeof(IEnumerator).GetProperty("Current").GetGetMethod()
),
PythonOperationKind.None
),
body,
UpdateLineNumber(list.Start.Line),
AstUtils.Empty()
),
else_,
breakLabel,
continueLabel
);
return(Ast.Block(
init,
Ast.TryFinally(
ls,
Ast.Call(AstMethods.ForLoopDispose, enumerator)
)
));
}
internal protected override Expression ToExpression(OverloadResolver resolver, RestrictedArguments args, bool[] hasBeenUsed)
{
var actualArgs = resolver.GetActualArguments();
int splatIndex = actualArgs.SplatIndex;
int collapsedCount = actualArgs.CollapsedCount;
int firstSplatted = actualArgs.FirstSplattedArg;
var result = new Expression[2 + _expandedCount + (collapsedCount > 0 ? 2 : 0)];
var arrayVariable = resolver.GetTemporary(_elementType.MakeArrayType(), "a");
int e = 0;
result[e++] = Ast.Assign(arrayVariable, Ast.NewArrayBounds(_elementType, Ast.Constant(_expandedCount + collapsedCount)));
int itemIndex = 0;
int i = _start;
while (true)
{
// inject loop copying collapsed items:
if (i == splatIndex)
{
var indexVariable = resolver.GetTemporary(typeof(int), "t");
// for (int t = 0; t <= {collapsedCount}; t++) {
// a[{itemIndex} + t] = CONVERT<ElementType>(list.get_Item({splatIndex - firstSplatted} + t))
// }
result[e++] = Ast.Assign(indexVariable, AstUtils.Constant(0));
result[e++] = AstUtils.Loop(
Ast.LessThan(indexVariable, Ast.Constant(collapsedCount)),
// TODO: not implemented in the old interpreter
// Ast.PostIncrementAssign(indexVariable),
Ast.Assign(indexVariable, Ast.Add(indexVariable, AstUtils.Constant(1))),
Ast.Assign(
Ast.ArrayAccess(arrayVariable, Ast.Add(AstUtils.Constant(itemIndex), indexVariable)),
resolver.Convert(
new DynamicMetaObject(
resolver.GetSplattedItemExpression(Ast.Add(AstUtils.Constant(splatIndex - firstSplatted), indexVariable)),
BindingRestrictions.Empty
),
null,
ParameterInfo,
_elementType
)
),
null
);
itemIndex += collapsedCount;
}
if (i >= _start + _expandedCount)
{
break;
}
Debug.Assert(!hasBeenUsed[i]);
hasBeenUsed[i] = true;
result[e++] = Ast.Assign(
Ast.ArrayAccess(arrayVariable, AstUtils.Constant(itemIndex++)),
resolver.Convert(args.GetObject(i), args.GetType(i), ParameterInfo, _elementType)
);
i++;
}
result[e++] = arrayVariable;
Debug.Assert(e == result.Length);
return(Ast.Block(result));
}
