From: Johan Nilsson <johan.nilsson@...>
Date: 2004-12-15T18:07:16+09:00
Subject: Re: Mixin questions


"Robert Klemme" <bob.news@gmx.net> wrote in message
news:328e5nF3jvaf9U1@individual.net...
>
> "Johan Nilsson" <johan.nilsson@---.esrange.ssc.se> schrieb im Newsbeitrag
> news:1103032112.3aa9129fd718fc17e4d9eb2e027a3e52@teranews...
> >
> > "Robert Klemme" <bob.news@gmx.net> wrote in message
> > news:3286taF3it29pU1@individual.net...
> > >
> >

[snip]

> >
> > I still don't see how the mixin can get to the protected methods
> though - I
> > get "NoMethodError: protected method 'my_stuff' called for ..." if I try
> > somehing like my original code.
>
> I haven't a solution for this yet.  I tried with instance_eval but to no
> avail.  Maybe send works.  Did you try that?

No, and it actually works. What's the difference? I'm just starting to use
Ruby for real.

>
> > > > In english, I want to create an instance of Foo from within the
> mixin's
> > > > supplied class method. The first question still applies though.
> > >
> > > You mean like this?
> > >
> > > module Mix
> > >   def test_it
> > >     p self::FOO
> > >   end
> > > end
> > >
> > > class Test
> > >   extend Mix
> > >   FOO = "bar"
> > > end
> >
> > Yes, but in my (unfortunately) more complex case I get "dynamic constant
> > assignment" whenever I add "self::<constant>" to the mixin (reported
> from
> > the point where the class constant is defined).
>
> But then you're assigning the constant more than once.  From your example
> I though you just wanted to access (= read) it.  Which Ruby version are
> you using?

Sorry for being unclear, but I'm not assigning more than once (at least I'm
not trying to). I'm trying to use either self::<constant> or
self.class.const_get(:<constant>) as rvalues, and the former does not work
in the Mixin. Oh, yes, and it is within a define_method scope - could that
matter, e.g.:

    def ...
        define_method(:initialize) { ||
            ...
            @x = self::<constant> # dynamic constant assignment
            ...
        }
    end

Platform is Ruby 1.8.2.rc9 on WinXP.

[...some minute later...] Oh, but wait - self refers to the object here.
Trying to use self.class::ID works! Sorry for the noise.

>
> > Using
> > ...self.class.const_get("<constant>") works fine though in the mixin.
>
> Strange.
>
> > The code is a bit too much to post though, if I can reduce it I'll try
> and
> > post the actual failing code instead.
>
> Yeah, it would be good to see the real source of the problem.  At the
> moment I feel a bit tapping in the dark. :-)

That might not be necessary any more, thanks!

// Johan