[cs] Added cs.StrictMeta

[waneck]

I'm submitting this as a pull request to request for comments - in special regarding:

1. the naming of the strict macro (@M(SomeClass))
2. If we could instead have a haxe.StrictMacro macro interface with about the same features

[nadako]

ouch, build-macros in std lib :-)

[ncannasse]

Just wanted to know about the context : is this something CS specific or particularly useful for CS dev ?

[waneck]

All native attributes in C# are type checked. The current native
implementation of native attributes in Haxe (via @:meta) however doesn't
type check them. And because of that, it's pretty confusing to work with
native attributes via Haxe. For example, if you want to use
cs.system.SerializableAttribute in a class, you'd need to use its native
type representation : @:meta (System.SerializableAttribute).
This macro does this conversion and type checks it.
I'm open to suggestions on better ways to implement this. Despite this
relating in special to C# an Java, maybe we can come up with an unified
(standard) way to deal with type check metas across all targets.

On Oct 21, 2014 4:29 PM, "Nicolas Cannasse" notifications@github.com
wrote:

Just wanted to know about the context : is this something CS specific or
particularly useful for CS dev ?

—
Reply to this email directly or view it on GitHub.

[waneck]

@nadako, indeed maybe an ocaml implementation would be best ;) . But then I think it would make more sense to just consider any @M() metadata as a strict meta (not need the implements StrictMeta at all), and make this construct "reserved".

[nadako]

@M looks quite arbitrary to be honest, maybe is it better to add some new syntax, e.g. @[] or whatever.

[waneck]

If @ncannasse agrees to something like that, I will be happy to work on it.
Maybe my last messages were a little confusing, so I'll try to clear it up what's the purpose of this:

• Both Java and C# (and possibly other targets - Flash maybe?) have native metadatas; They are however typed, and it is possible to import them, and necessary to type check them. In order to implement them correctly, we need to check them on the Haxe side as well.
• I agree that a macro solution looks kinda bad. Maybe we could add a better support for it by making some special construct that will be checked on typeload. I'll be glad to work on this - but it is possible that a new syntax will be needed so they don't clash with any other metadata
• In that sense, it would be great to add cross-target support for this, and add a mechanism to support this across all targets. I think this can become very useful, and even allow more macro possibilities (e.g. having a macro that gets activated when a special class is mentioned).

[waneck]

Superseded by #3954 3954