Default type parameters

[Simn]

Also pretty wippy, but let's have a PR!

[kLabz]

Good thing github has nice options!

[AlexHaxe]

please include an update for haxe.macro.Printer (needed by haxeparser tests and probably others)

[Simn]

I have disallowed usage on anything other than types and also adjusted haxe.macro.Printer. I think we're just about ready to merge this now!

[kLabz]

🎉

Is that a hard restriction or mostly to be done with the important part (types) and possibly implement the rest later?

[Simn]

Well, the main issue is still that there's no syntax to define the type parameters explicitly, and without that this feature makes no sense.

[Aurel300]

Should there be a check in the compiler that prevents type parameters without defaults to appear after type parameters with defaults? It makes sense syntactically, it is just really useless because:

class Example<T = Int, U = Int, V> { ... }

I cannot use the Example type unless I provide the third type parameter, which I can only do if I provide the first two type parameters as well.

[Aurel300]

And a separate question: why can the default not be a previous type parameter, as in:

class Example<T = Int, U = T> { ... }

[kLabz]

I specifically asked for typedef A = Example<_, _, String> back then and Simon seemed to agree but it seems like it wasn't implemented https://try.haxe.org/#DB2ECB50

I suppose the other question could be made to work too

[kLabz]

seems like that would make sense and be consistent, so we probably won't do it.

Ah yeah that may not exactly count as agreeing 😅