From: Robert Dober <robert.dober@...>
Date: 2006-08-18T05:09:31+09:00
Subject: Re: How to - Change operator behaviour

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On 8/17/06, Henry Savr <hsavr@yahoo.com> wrote:
>
> Dear Ruby gurus:
>
> I want to write anywhere in my code t1 > t2 and get:
>   - true if at least one parameter is nil and the other parameter is
> Time
>   - standard comparision result in other case
>
>
> How to do that?
>
> Thank you
> Henry
>
> --
> Posted via http://www.ruby-forum.com/.
>
>
Well if you really want to do that here you go
#!/usr/local/bin/ruby -w

class NilClass
    def > other
        return true if Time =3D=3D=3D other
        raise NoMethodError, "undefined method `>' for nil:NilClass"
    end
end

class Time
    alias_method :old_greater, :>
    def > other
        return true if other.nil?
        old_greater other
    end
end

def show bool, text1, text2
    puts bool ? text1 : text2
end

t1 =3D Time.new
t2 =3D Time.new

show t1 > t2, "error", "t1 is not > t2"
show t2 > t1,  "t2 > t1", "error"
show t1 > nil, "t1 > nil", "error"
show nil > t2, "nil > t2", "error"
nil > 2


Strange though??

Cheers
Robert

--=20
Deux choses sont infinies : l'univers et la b=EAtise humaine ; en ce qui
concerne l'univers, je n'en ai pas acquis la certitude absolue.

- Albert Einstein

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