From: Robert Klemme <shortcutter@...>
Date: 2006-12-06T21:45:06+09:00
Subject: Re: join_with

On 06.12.2006 11:40, Martin DeMello wrote:
> While golfing with the hex_ip thread, I realised that map takes no
> argument, and join takes no block, leaving a vacuum for a combined
> method:
> 
> module Enumerable
>  def join_with(sep, &blk)
>     map(&blk).join(sep)
>  end
> end
> 
> hex_ip.scan(/../).join_with('.') {|i| i.hex}
> 
> join_with is still a little clunky - any better name?

Hm.  I am not convinced this is a good idea at all.  Usually the 
recommendation is that methods should do one thing - and one thing only. 
  Combining map with join seems like a clear violation of that principle 
as map and join do extremely different things.

Having said that I'd prefer a more efficient implementation:

module Enumerable
   def jw( sep )
     first = true

     inject("") do |s, x|
       if first
         first = false
       else
         s << sep
       end

       s << yield( x )
     end
   end
end

Kind regards

	robert