From: Tomasz Wegrzanowski <taw@...>
Date: 2001-12-29T07:53:38+09:00
Subject: [ruby-talk:29596] extending method of class A to support arguments of class B by promoting `self' to class B

(Names of classes chosen arbitrarily, just to show issue)

Class Real has method `*' that can use argument Real.

I make class Complex. Class Complex also
has function `*' which can take either Real or Complex argument.
Object Complex can be created from Real by Complex.new(real_object).

I want to tell Ruby, that when Real object is called with Complex
argument it should be promoted to Complex and then appropriate
Complex method be called.

The only method I found is renaming all such methods to something
like `old_multiply', and redefining Real `*'. Is there any better way ?