From: Matthew Desmarais <desmarm@...>
Date: 2005-12-10T06:27:30+09:00
Subject: Re: different methods for initializing one object?

<snip>

>One way would be to take keyword arguments and figure out which you were 
>given.
>
>class Point2D
>  def initialize( params )
>    if params.has_key? :r and params.has_key? :theta
>      ## initialize from polar
>    elsif params.has_key? :x and params.has_key? :y
>      ## initialize from cartesian
>    else
>      raise ArgumentError.new( "You must provide either :r and :theta OR 
>:x and :y" )
>    end
>  end
>end
>
>cart = Point2D.new( :x => 42, :y => -4 )
>polar = Point2D.new( :r => 3.14159, :theta => (Math::PI/4) )
>  
>
Hi Mike,

What you've proposed is a fine idea, but I think that it's important to 
be clear about your terminology.  Ruby doesn't currently have keyword 
arguments.  In the example that you've provided you are passing a hash 
with symbols for keys into the initialize method and _not_ using keywords.

Regards,
Matthew J Desmarais