From: johan556@...
Date: 2007-03-21T08:32:37+09:00
Subject: Re: does Ruby not support multiple "initialize" methods for a class???

On 3/20/07, Greg Hauptmann <greg.hauptmann.ruby@gmail.com> wrote:
> Hi,
>
> Q1 - Does Ruby not support multiple "initialize" methods for a class?
>
> Q2 - If no is there a reason for this out of curiosity?
>
> Q3 - What approach is recommended if this constraint does exist?
>

I have been using the following pattern to implement multiple
constructors for a class. It is only a variation of the already
proposed solutions, but by using "instance_eval" I could avoid having
to create separate new/initialize-like methods for each constructor.

/Johan Holmberg

#-------------------------------
class Point

    def self.create_cartesian(x,y)
        allocate.instance_eval do
            @x = x
            @y = y
            self
        end
    end

    def self.create_polar(length,angle)
        allocate.instance_eval do
            @x = length * Math.cos(angle)
            @y = length * Math.sin(angle)
            self
        end
    end

end
#-------------------------------