From: Trans <transfire@...>
Date: 2005-12-06T11:33:02+09:00
Subject: Re: Overloaded constructors in Ruby

Timothy makes good points, but just so you understand how to write
alernate constructors for Ruby there are two weys.

First one can define alternate constructors:

  class GravPoint

    # however you wish to name them...

    def self.new_zero()
        new(0, 0, 0, 0, 0)
    end

    def self.new_lite(x, y, strength)
        new(x, y, strength, 0, 0)
    end

    def initialize(x, y, strength, ctime, life)
        @x, @y, @strength, @ctime, @life = x, y, strength, ctime, life
    end

  end

The other way is the use variable parameters. Something like:

     def initialize(*args)
        x, y, strength, ctime, life = 0,0,0,0,0
        case args.length
        when 0
          # good just the way it is, skip
        when 3
          x, y, strength = *args
        when 5
          x, y, strength, ctime, life = *args
        else
          raise ArgumentError
        end
        @x, @y, @strength, @ctime, @life = x, y, strength, ctime, life
     end

  T.