From: Adam Shelly <adam.shelly@...>
Date: 2008-04-01T03:27:19+09:00
Subject: Re: Modifying FIX::* method

On 3/31/08, Alex DeCaria <alex.decaria@millersville.edu> wrote:
> I want to be able to multiply a NUMERIC object by my Foo object and have
> it return a new Foo object with all the instance variables multiplied by
> the Numeric object.
[...]
> I'm thinking I have to modify the "*" method for all the subclasses of
> the NUMERIC class.  Is this correct?  Or am I missing something.
>

You don't need to modify Numeric, you just need to tell it how to
coerce your object into a number.

irb(main):057:0* class Foo
irb(main):058:1> def initialize(x)
irb(main):059:2> @x=x
irb(main):060:2> end
irb(main):061:1> def coerce(n)
irb(main):062:2> [n,@x]
irb(main):063:2> end
irb(main):064:1> end
=> nil
irb(main):065:0> 2 + Foo.new(3)
=> 5
irb(main):066:0> f=Foo.new(4)
=> #<Foo:0x283b13c @x=4>
irb(main):067:0> 8/f
=> 2

-Adam