From: Mark Hahn <mchahn@...>
Date: 2001-12-29T07:59:42+09:00
Subject: [ruby-talk:29597] RE:  extending method of class A to support arguments of class B by promoting `self' to class B


> it should be promoted to Complex

Is this possible?  I've wanted to change an object's type before inside a
method of that object, but I didn't think it was possible.

Or did you mean "return" a Complex object.  That is all you really need to
do in the case you describe.

-----Original Message-----
From: Debian User [mailto:taw@pa76.chojnow.sdi.tpnet.pl]On Behalf Of
Tomasz Wegrzanowski
Sent: Friday, December 28, 2001 2:54 PM
To: ruby-talk ML
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 ?