From: Jules <julesjacobs@...>
Date: 2006-01-21T02:01:05+09:00
Subject: Re: Newbie ahead!: Ruby-Demo

Show them: blocks, OOP, "the Ruby way".

(0..10).map{|x| x*x}.select{|x| x < 50}

Take a Java program and translate it to ruby step-by-step by stripping 
things ;-)

-----

class Person
  def initialize(newName)
    @name = newName
  end

  def getName()
    return(@name);
  end

  def setName(newName)
    @name = newName;
  end
end

=>

class Person
  def initialize(new_name)
    @name = new_name
  end

  def name
    @name
  end

  def name=(new_name)
    @name = new_name
  end
end

=>

class Person
  attr_accessor :name
end

=>

Person = Struct.new(:name)

...

people = [Person.new('David'), Person.new('Amy'), Person.new('Paul')]
people.sort_by{|p| p.name}

...

# Struct.new returns a class, so we can subclass it :)

class Person < Struct.new(:name)
  include Comparable

  def <=> other
    @name <=> other.name
  end
end

people = [Person.new('David'), Person.new('Amy'), Person.new('Paul')]

# A person has comparison methods now. > == < <= >= etc. can be used 
now.
# The people Array has includes?, max, min etc.
# Everything just by adding include Comparable and def <=>.

if people[0] < people[1] && people.includes? Person.new('David')
  people.sort!
end

-----

All untested.

Jules

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