From: "Pieter V." <pvande@...>
Date: 2007-05-20T06:01:50+09:00
Subject: Re: Block Trouble (Binding Issue?)

Arg.  Thanks.  I would have sworn I tried that at some point.  Works
like a charm.

On 5/19/07, Joel VanderWerf <vjoel@path.berkeley.edu> wrote:
> Pieter V. wrote:
> > I'm presently trying to work on a little metaprogramming project, but
> > am finding my efforts a little frustrated by ... well, I'm not rightly
> > sure what by.  It seems to be a scoping issue, from what I can tell.
>
> Yup, it sure is. define_method(name, &block) changes the scope of block
> to the instance, but the yield still references a block in class Foo scope.
>
> A fix might be to replace yield with instance_eval(&b), as below, but
> that will preclude passing arguments to the block, in case you ever need
> to do that. Google for instance_exec for a discussion, hacks for the
> present, and hope for the future (1.9 has it)...
>
> >  def self.special_meth(name, &b)
> >    meth(name) do
> >      # do something special
> >      yield # <= This is the problematic call
>         instance_eval(&b)
> >    end
> >  end
> > end
>
> --
>        vjoel : Joel VanderWerf : path berkeley edu : 510 665 3407
>
>