From: 7stud -- <bbxx789_05ss@...>
Date: 2011-05-14T02:50:13+09:00
Subject: Re: Scope problem (?) in implementing Design Patterns in Ruby

RichardOnRails wrote in post #998460:
>
> I have only one question: I put a space between the & and the method
> following it; the code broke.  Is the construct you used documented on-
> line somewhere?  I've peeked at lambda documentation so I've got the
> drift but I haven't used it in any of my code so far.
>

Your bible, "The Well-Grounded Rubyist" uses the &:meth_name construct a 
lot, and David Black says that the '&' in '&:meth_name' does two things:

1) It calls the specified object's to_proc() method.  And Symbol#to_proc 
is defined like this:

class Symbol
  def to_proc
    proc{|obj, *args| obj.send(self, *args)}
    #self=:meth_name
  end
end

That just creates a function that takes an object as an argument and 
sends() the :meth_name to the object, i.e. the function calls the 
:meth_name method on the object.

2) The '&' tells ruby to convert the Proc to a block.

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