For loop picks conversion to an Iterator over .iterator()

[Ondřej Műller]

It seemed strange because I did not know for loop uses the same mechanism as all of haxe(namely conversions). It makes sense if you try it against Iterator<T> and then Iterable<T> in order.

Instead of checking it in series, it could check in parallel - see if it's directly Iterator<T>, then Iterable<T>, then look for conversions to first, to second... whatever the priority list is.

This would make more sense. Or is this intended?

[Dan Korostelev]

Could you elaborate? What "conversions" are you talking about? Could you show some code to make it easier understand the issue?

вторник, 19 июля 2016 г., 2:26:14 UTC+3 пользователь Ondřej Műller написал:

[Ondřej Műller]

User-defined conversions for abstracts, @:from and @:to.

Example here:

package;

class AClass {
    public function new() {}
   
    public function iterator():Iterator<String> return new AIterator(this);
}
@:forward()
abstract A(AClass) from AClass to AClass {
    public function new() {
        this = new AClass();
    }
   
    @:to
    function toB() return new B();
}
class AIterator {
    public function new(a:A) {}
   
    public function hasNext() return true;
    public function next() return "AIterator";
}
class B {
    public function new() {}
   
    public function hasNext() return true;
    public function next() return "B";
}
class Main {
    public static function main() {
        var iter = new A();
        for (s in iter) {
            trace(s);
            break;
        }
        for (s in iter.iterator()) {
            trace(s);
            break;
        }
    }
}