From: Kyle Heon <kheon@...>
Date: 2005-12-06T10:21:50+09:00
Subject: Overloaded constructors in Ruby

I have a class that I want to have a number of overloaded constructors for.

I tried doing something like this:

class GravPoint
    def initialize()
        this(0, 0, 0, 0, 0)
    end

    def initialize(x, y, strength)
        this(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

When I then run GravPoint.new() I get the following error:

GravPoint.rb:23:in `initialize': wrong number of arguments (0 for 5)
(ArgumentError)

I think I understand the error, it's expecting 5 arguments (based on the
last constructor) but I don't the "Ruby" way to set this up. What am I
missing?

I was able to get this to work, but was hoping that I could do it in a
format closer to the above to make it a little more flexible to use.

class GravPoint
    def initialize(x = 0, y = 0, strength = 0, ctime = 0, life = 0 )
        @x, @y, @strength, @ctime, @life = x, y, strength, ctime, life
    end
end

Kyle Heon
kheon@comcast.net