From: Tom Link <micathom@...>
Date: 2009-02-03T15:21:48+09:00
Subject: Re: choose parameter to solve for

>     if @x.nil?
>       @x = var

This could be rewritten as

        @x ||= var

>     elsif @y.nil?

What if @x and @y are nil? You might want to use

        @y ||= var
        @z ||= var

instead -- depending on what you want of course.