From: Sean O'Halpin <sean.ohalpin@...>
Date: 2006-07-02T09:52:08+09:00
Subject: Re: Arrray#to_proc

On 7/1/06, Alex Young <alex@blackkettle.org> wrote:
> Matthew Harris wrote:
> > I don't know if this was posted previously, but I had the idea of a
> > Array#to_proc, an example would be:
> >
> > [9, 19, 29].map(&[:succ, :to_s, :reverse])
> > => ["01", "02", "03"]
> >
> > I've seen people ask questions such as arr.map(&'meth1.meth2.meth3')
> > but I think using the Array#to_proc solution is cleaner.
> >
> > Would this actually prove useful? It would seem that using the normal
> > block form would be just as much typing, though.
> >
> I'd rather do this:
>
> class Proc
>    def +(other)
>      proc {|*args|
>        args = [self.call(*args)]
>        other.call(*args)
>      }
>    end
> end
>
> [9, 19, 29].map( &:succ + &:to_s + &:reverse )
> #=> ["01", "02", "03"]
>
> but I'm just weird like that :-)
>
> Is this useful for anything?  It looks like it should be, but I can't
> think of what...
>
> --
> Alex
Hi,

I get a "parse error, unexpected tAMPER" with ruby 1.8.4 (2005-12-24)
[i386-mswin32].
What version are you using?

How about something like this:

module Enumerable
  def cascade(*methods)
    methods.inject(self) { |ary, method| ary.map{ |x| x.send(method)}}
  end
end

res = [9, 19, 29].cascade :succ, :to_s, :reverse
p res
#=> ["01", "02", "03"]

Unless you prefer the line noise of course ;)

Regards,
Sean