public override IValue interpret(Context context)
{
IType sourceType = source.check(context);
if (!(sourceType is IterableType))
{
throw new InternalError("Illegal source type: " + sourceType.GetTypeName());
}
IType itemType = ((IterableType)sourceType).GetItemType();
IValue value = source.interpret(context);
if (value == null)
{
throw new NullReferenceError();
}
if (!(value is IFilterable))
{
throw new InternalError("Illegal fetch source: " + source);
}
IFilterable list = (IFilterable)value;
ArrowExpression arrow = predicate.ToArrowExpression();
Predicate <IValue> filter = arrow.GetFilter(context, itemType);
return(list.Filter(filter));
}
public override ArrowExpression ToArrowExpression()
{
ArrowExpression arrow = new ArrowExpression(new IdentifierList(itemName), null, null);
arrow.Expression = predicate;
return(arrow);
}
private IType checkPredicate(Context context)
{
IType lt = left.check(context);
if (lt is IterableType)
{
IType itemType = ((IterableType)lt).GetItemType();
ArrowExpression arrow = ((PredicateExpression)right).ToArrowExpression();
return(arrow.CheckFilter(context, itemType));
}
else
{
throw new SyntaxError("Expecting collection");
}
}
IValue interpretPredicate(Context context)
{
IValue lval = left.interpret(context);
if (lval is IContainer)
{
IType itemType = ((ContainerType)lval.GetIType()).GetItemType();
ArrowExpression arrow = ((PredicateExpression)right).ToArrowExpression();
Predicate <IValue> predicate = arrow.GetFilter(context, itemType);
return(interpretPredicate(context, (IContainer)lval, predicate));
}
else
{
throw new SyntaxError("Expecting collection");
}
}
public override IType check(Context context)
{
IType sourceType = source.check(context);
if (!(sourceType is IterableType))
{
throw new SyntaxError("Expecting an iterable type as data source!");
}
IType itemType = ((IterableType)sourceType).GetItemType();
ArrowExpression arrow = predicate.ToArrowExpression();
IType filterType = arrow.CheckFilter(context, itemType);
if (filterType != BooleanType.Instance)
{
throw new SyntaxError("Filtering expresion must return a bool!");
}
return(new ListType(itemType));
}
internal ArrowComparer2Args(Context context, bool descending, ArrowExpression arrow)
: base(context, descending, arrow)
{
}
internal ArrowComparer(Context context, bool descending, ArrowExpression arrow)
{
this.context = context;
this.descending = descending;
this.arrow = arrow;
}
