From: John Lam <drjflam@...>
Date: 2006-08-31T03:25:09+09:00
Subject: Re: Obtaining a reference to an enclosing class of a nested class

Yep - they're anonymous. I'm rewriting how RubyCLR deals with shadow
class references to generic types, and I've made a design decision
that shadow classes don't really need names. The anonymous class
objects are bound to constants only when necessary (I could avoid this
too, but I haven't measured how expensive calls to const_missing vs. a
hit on a constant are - I suspect it's faster to have constants
pre-created).

I used to mangle class names so that:

List<String>

becomes

List_generic_System_String

but this becomes insanely complex when you consider all of the corner
cases involving generic types and nested generic types. I cut a ton of
complexity out of the code by simply not naming the classes anymore.
That works until this case.

Right now I'm explicitly adding a back-reference to the anonymous
class objects that I create which works just fine. I was just
wondering if there was something in the Ruby type system that would
let me do this already so that I'm not wasting memory duplicating
something that I can already do.

I'm fairly certain that I can't do this, but I thought I'd run it past
folks with more experience than me.

Cheers,
-John
http://www.iunknown.com




On 8/30/06, Rick DeNatale <rick.denatale@gmail.com> wrote:
> On 8/30/06, John Lam <drjflam@gmail.com> wrote:
> > Here is a nested class definition:
> >
> > class A
> >   class B
> >   end
> > end
> >
> > Now, if I have a reference to class B from somewhere:
> >
> > def get_reference
> >   A::B
> > end
> >
> > reference_b = get_reference
> >
> > How can I get a reference to the enclosing class A?
>
> Well in this case, since we know(?) it's a Class or Module:
>
>    reference_b.name => "A::B"
>
> So you can get A's name by string manipulation.
>
> > I can't do this by symbol lookup since class A (and B for that matter)
> > are anonymous. Am I going to have to explicitly create a
> > back-reference to the enclosing class at the time that I create class
> > B?
>
> Do you really mean that they are anonymous, or that you don't directly
> know the name?
>
> --
> Rick DeNatale
>
> My blog on Ruby
> http://talklikeaduck.denhaven2.com/
>
>