From: dblack@...
Date: 2003-02-21T21:22:05+09:00
Subject: Re: proc {} vs. Method#to_proc

Hi --

On Fri, 21 Feb 2003, Mauricio [iso-8859-1] Fern�ndez wrote:

> On Fri, Feb 21, 2003 at 06:03:38AM +0900, dblack@candle.superlink.net wrote:
> > Hi --
> >
> > On Fri, 21 Feb 2003, Mauricio [iso-8859-1] Fern�ndez wrote:
> >
> > > On Fri, Feb 21, 2003 at 01:19:17AM +0900, dblack@candle.superlink.net wrote:
> > > > Hi --
> > > >
> > > > Arising from a recent discussion on #ruby-lang:
> > > >
> > > > Proc objects created by Method#to_proc seem to care about their arity
> > > > in a way that other Proc objects don't.  To illustrate:
> > >
> > > Procs don't care about the arity when they are transformed into blocks
> > > with '&': unneeded arguments are discarded and if there's not enough
> > > they get filled with nil.
> >
> > But that isn't what's happening with the to_proc procs.  That's why
> > their behavior strikes me as anomalous.
>
> Read the rest of my message :)
>
> to_proc works like
>  proc { |*args| self.call(*args) }
> calling the block works (it accepts any number of args, so even .call
> would), self.call fails.
>
> You can use #my_to_proc in [ruby-talk:65372] to make these procs behave like the
> others.

I understand that (we were already playing around with
reimplementations in the original irc session on this :-) but my point
was that I think that the behavior of these procs is potentially
misleading and I wonder whether it should (or could) be changed in the
language itself.  Somehow "to_proc" doesn't convey the idea of a
wrapper of this kind to me.


David

-- 
David Alan Black
home: dblack@candle.superlink.net
work: blackdav@shu.edu
Web:  http://pirate.shu.edu/~blackdav