From: Michael Neumann <neumann@...>
Date: 2001-11-30T01:19:44+09:00
Subject: [ruby-talk:26925] Re: short article draft for review

Tobias Reif wrote:
> Hi,
> 
> here is a draft for a very short article about Ruby. All in all I want 
> to leave it like it is, but if you find major errata/bugs/issues, please 
> post corrections/fixes. (or mail 'em offlist; it's probably not worth a 
> big thread)
> 
> Easy to extend existing classes:
> 
> class Numeric
>    def pos
>      if self < 0
>        0
>      else
>        self
>      end
>    end
> end
> puts  4.pos
> puts  0.pos
> puts -4.pos

It's a great feature but should be used with caution, because
it has a global change.

> Recursion, blocks as arguments:
> 
> def upto limit,current=1,&block
>    yield current
>    if current < limit
>      upto limit,current+=1,&block
>    end
> end

Recursion is no special feature of Ruby. 
Almost every language has it.

> ----------------------------------------
> 
> Objects:
> 
> class Digits_to_english < String
>    def to_e
>      self.scan(/\d/).map do |digit|
>        case digit
>          when '0' then 'zero'
>          when '1' then 'one'
>          when '2' then 'two'
>          when '3' then 'three'
>          when '4' then 'four'
>          when '5' then 'five'
>          when '6' then 'six'
>          when '7' then 'seven'
>          when '8' then 'eight'
>          when '9' then 'nine'
>        end
>      end
>    end
> end
> 
> d2e = Digits_to_english.new '55793'
> puts d2e
> puts d2e.to_e
> 
> # 55793
> # five
> # five
> # seven
> # nine
> # three

I don't get the point here. Why do you call it "Objects".
Wouldn't "Classes" as title be better?
Or perhaps "Everything is an object", even classes ?

For me, this is also very interesting:

  p (10 ** 1000)


Singleton methods:

  a = "test"
  def a.output
    print self.to_s
  end
  
  a.output
  b = a
  b.output     # OK

  b = "test"
  b.output     # Error
  
Mix-ins (instead of multiple inheritance):

  module B
    def test
    end
  end

  class A
    include B
  end

  A.new.test


Regards,

  Michael

-- 
Michael Neumann
merlin.zwo InfoDesign GmbH
http://www.merlin-zwo.de