#!/usr/bin/env ruby
# This code comes from http://ruby-it.org/pages/Oggetti+Proc+e+Method
# Check the page for copyright notice and explanations



 # primo metodo                  
 prc=Proc.new do |arg|
      ...codice..
     end

 # secondo metodo
 prc=proc do |arg|
      ...codice..
     end

 # terzo metodo
 prc=lambda do |arg|
      ...codice..
     end

 >> p=Proc.new {|a,b| puts a,b }
 => #<Proc:0x401f9570@(irb):1>
 >> f=lambda {|a,b| puts a,b }
 => #<Proc:0x401f61b8@(irb):2>
 >> p.call 1,2
 1
 2
 => nil
 >> f.call 1,2
 1
 2
 => nil
 >> p.call 1
 1
 nil
 => nil
 >> f.call 1
 ArgumentError: wrong number of arguments (1 for 2)
         from (irb):2
         from (irb):2:in `call'
         from (irb):6

 p= lambda {|z| print z }
 p(10) # sintassi come in python o scheme

 p= lambda {|z| print z }
 p.call(10) # simile a funcall in Common LISP

 p= lambda {|z| print z }
 p[10] # equivalente a p.call(10)

 met=method(:nomemetodo)

 met=oggetto.method(:nomemetodo)

 def fun(a)
  a**2
 end
 nil
 oggetto=method :fun # #<Method: Object#fun>
 oggetto.call(10) # 100
 oggetto[10] # uguale a call()