From: Sebastian Hungerecker <sepp2k@...>
Date: 2007-11-21T02:24:55+09:00
Subject: Re: Quick way to get attributes (without using collect)

Max Williams wrote:
> This was inspired by Rails, but i think it's common Ruby question. 
> [...]
> What i want to do is something like this -
>
>   employee_names = employees.names
>
> But what i have to keep on doing is something like this -
>
>   employee_names = employees.collect{ |emp| emp.name}

In rails you can do "employee_names = employees.collect(&:name)" which is
somewhat more concise (though it incurs a performance penalty, I am told).

> Is there a way to set it up so that
> .foos
> is automatically treated as
> .collect { |x| x.foo }

module Enumerable
  def method_missing(meth, *args, &blk)
    map {|x| x.send(meth,*args, &blk)}
  end
end

This might easily lead to bugs though if you want to invoke  method on the 
elements of the enum, not considering or not knowing that the enum itself 
implements that method as well. For example:
[2,4,6] / 2 #=> [1, 2, 3]
But:
[2,4,6] * 2 #=> [2,4,6,2,4,6]

Or:
["1","2","3"].to_i #=> [1, 2, 3]
But:
[1,2,3].to_s #=> "123"


HTH,
Sebastian
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