From: transfire@...
Date: 2006-07-15T21:25:29+09:00
Subject: Re: Preferred monkeypatching technique


Daniel Martin wrote:
> Eric Hodel <drbrain@segment7.net> writes:
>
> > You don't need a mutex.
> >
> > class Symbol
> >   @gensym_count = 0
> >   def self.gensym
> >     ("__gensym__%X" % @gensym_count += 1).intern
> >   end
> > end
>
> Okay, but now if two different files include this exact code, you're
> re-generating the same symbols.  This is why I used ||=, making your
> code:
>
> class Symbol
>   @gensym_count ||= 0
>   def Symbol.gensym
>     ("__gensym__%X" % @gensym_count += 1).intern
>   end
> end

What if the symbol is already used?

  define_method( :__gensym__0 ) do
    ...
  end

  Symbol.gensym  => :__gensym__0

I know, unlikley, but gensym's return is not neccessarily unique.

T.