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");
}
}
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));
}