Typed Array casting

[David Mouton]

Hi,
 I want to test the type of an anonymous object, supposed to be an Array<Order>

I try this :

if(Std.is(data, Array<Order>) ){
                Log.trace("return ok");
            } else {
                Log.trace("type error : " + message.data);
            }

But the compiler is not happy and says :
characters 31-32 : Unexpected )

Any idea ?

[Simon Krajewski]

Type parameters are not allowed in expressions. The parser will read this as a < binop between Array and Order, and then a > binop between that and ), which makes no sense grammar-wise.

In general, type parameter information is not available at runtime across platforms. You can work around this in several ways, e.g. by testing the type of data[0] against Order after confirming that data is an Array of non-zero length.

Simon

[Juraj Kirchheim]

Type parameters are lost at runtime, with the exception of classes implementing `haxe.rtti.Generic` (and types marked as @:generic under Haxe 3).

Please note that it is also syntactically impossible. The easiest way to do it is to have a typedef for the given type, e.g.:

     typedef IntFastList = haxe.FastList<Int>;

     trace(Std.is(someValue, IntFastList));

The same is valid Haxe code for arrays as well, but checking an array of strings against IntArray would still yield true, because Array is not Generic.

Regards,

Juraj