From: matz@... (Yukihiro Matsumoto)
Date: 2002-05-10T17:37:11+09:00
Subject: Re: Reversing receiver and argument for commutative math operations


In message "Reversing receiver and argument for commutative math operations"
    on 02/05/10, "Gray, Jeff" <jeff.gray@intel.com> writes:

|Let's say I have a class that overrides certain arithmetic operators like +
|and *, so that
|
|  obj = MyClass.new(5, "some other attribute")
|  this_obj = obj * 2    # this_obj == MyClass.new(10)
|  that_obj = 2 * obj    # that_obj == this_obj is desired

|Is there a way to do what I'd like?

How about

   class MyClass
     def initialize(v)
       @value = v
     end
     def value
       @value
     end
     def *(x)
       if x.type <= self.type
         x = x.value
       end
       self.type.new(self.value * x)
     end
     def coerce(x)
       [self.type.new(x), self]
     end
   end

   p MyClass.new(1) * 2
   p 2 * MyClass.new(2)

							matz.