From: Andrew McGuinness <a.mcguinness@...>
Date: 2006-01-04T05:57:57+09:00
Subject: Re: Implicit block parameter?

gabriele renzi wrote:
 >
 > True, but considering how often people write
 >  each {|x| stuff(x)}
 > I don't think it would be a great less in readability.
 > Not really advocating "it", but neither against it. No pun intended.

Another way of dealing with it would be if it were easier to get from a
method to a Proc object, so instead of, say

heads = queues.map { |x| x.first }

You could have something more like:

heads = queues.map( &:first )

As with the "it" thing, you can do it for a specific method -

module Enumerable
    def map_method( method, *args )
      map { |x| x.send( method, *args ) }
    end
end

heads = queues.map_method( :first )

For  things.each { |x| stuff(x) }  it's possible in principle:

things.each( &method(:stuff).to_proc )

But that's not exactly a simplification - I'm hoping for something more
like lisp, where:

(setq heads (mapcar (lambda (x) (first x)) queues))

can be replaced exactly by:

(setq heads (mapcar #'first queues))


I don't know if there's a good way of doing what I want - Ruby is
fundamentally unlike lisp in that objects are more fundamental than
functions.  I think it would be possible to allow Symbol and Method as
alternatives to Proc in a "block" parameter, but I'm not sure it would
be a good idea.

heads = queues.map( &:first )

things.each( &method(:stuff) )

--
Andrew McGuinness
http://anomalyuk.blogspot.com/