From: Steve Messamore <stevemessamore@...>
Date: 2008-10-07T03:58:14+09:00
Subject: Re: Unary operator

stephan.zimmer wrote:
> Hi all,
> 
> here is a novice's question: I am wondering how to equip a class with
> a unary operator. Defining a method "-" like this
> 
> class Something
>   # ...
> 
>   def -
>     # some code
>   end
> 
>   # ...
> end
> 
> I have to call "-" by writing
>   somethingelse = something.-
> 
> Is there a possibility to write this in prefix notation?
>   somethingelse = -something
> 
> Thanks in advance, best,
> 
> Stephan

Hi Stephan,
This shows binary and unary operator definitions.
Hope it helps.



class Sam
   attr_accessor :me

   def initialize(me='This is a default: ')
     @me = me
   end

   "Binary Operator"
   def + (arg)
     self.me + arg.to_s
   end

   "Unary operator"
   def -@
     self.me.reverse
   end
end

x = Sam.new('Test ')
p x + 'Test'
p -x

Cheers,
Steve