From: Its Me <itsme213@...>
Date: 2004-04-08T05:14:18+09:00
Subject: Re: Idea: Simplified GTK


"Hal Fulton" <hal9000@hypermetrics.com> wrote in message
news:407444BD.1090604@hypermetrics.com...
> You coded the same thing I did in half the time, and it's prettier. I
> find that disgusting.  ;)
>
> I was using an explicit stack in a class variable for the containers.
> This is much nicer, and I need to eyeball it and make sure I get it.

Dynamically scoped variables do precisely what your "explicit stack" was
doing:

http://pragprog.com/pragdave/Tech/Random/StackContext.rdoc

The code I posted elsewhere on this thread uses Avi Bryant's implementation.
It let's us set up defaults with systematic overriding, including default
blocks:

class A
    @@defaults = {:HBox => {:fill => ....} }
end

def foo
    with_context (:A.defaults) {
        bar
    }
end

def bar
    with_context ( {:other => "stuff"} ) {
        baz
    }
end

def baz
    ...find_in_context (:other)
    ...find_in_context (:HBox)
    ...find_in_context [:HBox, :fill]
end

(Avi Bryan't startlingly concise implementation uses continuations.
Continuations make my head hurt but they sure seem to be powerful things).