From: Trans <transfire@...>
Date: 2006-08-31T01:20:35+09:00
Subject: Re: Matz' Wild Ideas: Annotations


Matt Todd wrote:
> class X
>   def foo arg1
>     # do stuff here
>   end
>   annotate :foo do
>     requires "arg1 >= 10" # or whatever it takes
>     overriding true
>     visibility public # though I think what we've now works well
>   end
> end
>
> I like your last try, Trans, but it just doesn't sit too well with me.
> This example above is about as verbose as I'd like it... #annotate
> being a class method that actively annotates the methods properties.
> This way _could_ be easier to implement, and less destructive of the
> current syntax. (I like that.) Plus, it's a method, so it doesn't
> matter where or when you call it.
>
> Also, I don't think we should duplicate visibilitiy... there's a
> reason we have what we already have for defining public and private
> and protected.
>
> One of my biggest concerns/thoughts, really, is how to preserve the
> test "arg1 >= 10" to be both reprintable and testable. I mean, I guess
> it could be done with some hacking to get the binding of the method
> and then #eval it with that binding, but still, you're passing a
> string as a test.
>
> I understand and agree with you, Francis: annotations open up quite a
> bit. In fact, it's a step towards good AOP (Aspect Oriented
> Programming). (Or am I thinking of another term... crap, where's my
> PragProg book!?) But, on configuration vs. convention, it would be
> perfectly sufficient to have a conventional annotation, and from
> there, anything specific just overrides it. That way we don't have to
> worry about breakage and for those that are perfectly happy with the
> way things are now (a good majority of the people) can go on their
> merry way. Is there any other way!? :)

FYI. I'm working on this for next version of Facets' Annotations
system.

Thanks,
T.