From: Ross Bamford <rossrt@...>
Date: 2006-05-08T23:37:41+09:00
Subject: Re: Raw idea about Proc

On Mon, 2006-05-08 at 23:07 +0900, Victor Shepelev wrote:
> Hi all.
> 
> There is the idea (in VERY dirty code):
> --
> class Proc
>   def bound; @bound ||= {} end
>   def bind(num, val)
>     bound[num - 1] = val
>   end
> 
>   alias :old_arity :arity
>   def arity
>     old_arity - bound.size
>   end
> 
>   alias :old_call :call
>   def call(*arg)
>     bound.to_a.reverse_each{|num, val| arg.insert(num, val)}
>     old_call(*arg)
>   end
> end

There are a few drawbacks to this approach I think, most of which I
forget right now. A probable biggie is that it won't work with yield:

l = lambda { |num,ele| p num, ele }
l.bind(0,10)

[1,2].each &l
# 1
# nil
# 2
# nil

Maybe check out http://rubymurray.rubyforge.org , which does similar
stuff but by wrapping up the proc (still has limitations, but there you
go...)

-- 
Ross Bamford - rosco@roscopeco.REMOVE.co.uk