From: Trans <transfire@...>
Date: 2007-07-19T01:17:26+09:00
Subject: Re: Are we cool? method_missing in enumerator



On Jul 18, 8:01 am, Sammy Larbi <s...@powersource.com> wrote:
> I might test that it can still throw missing method exception if the
> called method isn't supposed to be doing what you're making it do (ie,
> perhaps it was a typo)
>
> Sam
>
> Trans wrote, On 7/17/2007 9:01 AM:
>
> > Can anyone demonstrate problems with the following?
>
> >   # Adds immediate elementwise ability to Enumerator.
> >   # Any non-enumeration method is passed on to each.
> >   #
> >   #   [1,2,3].to_enum(:map) + 3
> >   #   => [4,5,6]
> >   #
> >   # Note there may be a few essential methods this can not
> >   # be used on, such as #object_id.
>
> >   class Enumerable::Enumerator
> >     def method_missing(sym,*args,&blk)
> >       each{ |x| x.send(sym,*args,&blk) }
> >     end
> >   end
>
> > I like the simplicity of this and would rather use it than add an
> > another class layer, but I need to be sure I'm not overlooking any
> > potential dangers with doing so.

Yea, that's the "danger" part, because it's going to try to apply that
typo to the enumerable's elements. I many cases that will no doubt
fail --in which case maybe it wouldn't hurt to but it in a begin
rescue clause in order to give a more comprehensible error message.
OTOH, some typos might get through, in which case testing is key.

I think I've come up with a good alternative that is safer, but still
reads well (as of 1.9):

  arr.map.x + 3

What do you think?

T.