From: Gavin Sinclair <gsinclair@...>
Date: 2003-09-03T10:41:05+09:00
Subject: Re: OOP flavours - was Python vs. Ruby

> On Wed, 3 Sep 2003 09:33:02 +0900
> David Naseby <david.naseby@eonesolutions.com.au> wrote:
>
> <snip>
>> I like this style too, and Ruby allows one to do it well via Mixin
>> Oriented Programming (MOP?). The best library based example I've seen
>> is in Amrita, where you extend your model class with
>> Amrita::ExpandByMember, so amrita can render the object correctly.
>>
>> Similarly, you don't need to expand classes to predict there uses -
>> for the example of IO printing flying around, you can extend on the
>> fly:
>>  module STDOUTPrinter
>>    def print
>>      STDOUT.print self.to_str
>>    end
>>  end
>>
>>  str = "helloworld"
>>  str.extend STDOUTPrinter
>>  str.print
>>
>> Its a fairly useless example in this case, but extend this to template
>> based GUIs along the amrita lines, and mixin oriented programming
>> shows its real strength.
> <snip>
>
> Actually this isn't a very good example.  This whole argument about
> "print should be a member of an object" is demonstrably inelegant and
> wrong, for a number of reasons (some of which have been noted already):
>
> [...]

I'm surprised nobody has mentioned the built-in method Object#display.  It
is analogous to String#print, and gives the lie to the notion that you
need to also implement Fixnum#print, Range#print, etc.

--------------------------------------------------------- Object#display
     obj.display( port=$> ) -> nil
------------------------------------------------------------------------
     Prints obj on the given port (default $>). Equivalent to:
        def display(port=$>)
          port.write self
        end
     For example:
        1.display
        "cat".display
        [ 4, 5, 6 ].display
        puts
     produces:
        1cat456


Personally I never use it, for all the reasons that have been given, and
one more: I prefer #puts to #write.

Gavin