From: Matt Todd <chiology@...>
Date: 2006-08-28T03:08:36+09:00
Subject: Re: Matz' Wild Ideas: Annotations

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!? :)

Cheers,

M.T.