From: Ruby Freak <twscannell@...>
Date: 2008-06-28T03:17:39+09:00
Subject: Explanation of overriding method with lambda

Hi,

I am reading the tutorial at:
http://en.wikibooks.org/wiki/Programming:Ruby_Method_Calls

and I understand everything except this last method override code.

We had this,(line below) which is simple and we are overriding to make
it "better"
upcase_words = words.map {|x| x.upcase}


 class Symbol
     # A generalized conversion of a method name
     # to a proc that runs this method.
     #
     def to_proc
         lambda {|x, *args| x.send(self, *args)}
     end
 end

 # Voila !
 words = %w(Jane, aara, multiko)
 upcase_words = words.map(&:upcase)

So we are overriding the to_proc method with
lambda {|x, *args| x.send(self, *args)}

so in the lambda, the x in |x, args| is the same as the |x| in the
block (Jane, aara, multiko)(yes?, no?)

and the args in |x, args| is the symbol :ucase, (yes?, no?)

I don't understand x.send(self, *args)
self is the symbol :ucase ?
but so is args ???

In my brain, at some point I get "jane.send(self, *args)"

I'm lost.

I do understand the concept of opening a class and overriding a
method, just not the details here.

Thank in advance