From: Eric Mahurin <eric_mahurin@...>
Date: 2005-10-26T04:33:28+09:00
Subject: Re: Redefine minus unary method

Fixnum overrode -@ but not +@.  Redefining the superclass
method doesn't do any good if you are using the sub-classes and
they overrode the methods.  You need to redefine Fixnum#-@ and
Bignum#-@ if you want to do this.  Be warned though -
redefining core class methods can result in inconsistent
behavior because some places may bypass the normal method call
mechanism or not use the methods you expect.  I think it best
not to redefine core class methods or sub-class core classes. 
You are just asking for trouble when you do that.

--- David Tran <email55555@gmail.com> wrote:

> class Integer
>   def +@
>     super
>     puts 'redefine + unary'
>     self
>   end
> 
>   def -@
>     super
>     puts 'redefine - unary'
>     self
>   end
> end
> 
> +(2)  # print out 'redefine + unary'
> -(2)  # nothing print out, why ?
> 
> a = 4
> a = +a  # print out 'redefine + unary'
> a = -a  # nothing print out, why ?
> 
> 



		
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