From: dblack@...
Date: 2007-01-04T10:21:46+09:00
Subject: Re: Little Things

Hi --

On Thu, 4 Jan 2007, ara.t.howard@noaa.gov wrote:

> On Thu, 4 Jan 2007 dblack@wobblini.net wrote:
>
>>> hmmm.  there is no way around this kind of thing unless the operation of
>>> sending a message to an object is removed from the object's interface.  so 
>>> we
>>> could have something like
>>>
>>>  Pervasives.send obj, message, *args, &block
>>> 
>>> here Pervasives is an object that cannot be changed - even by changing
>>> Object#send.
>>> 
>>> this also allows
>>>
>>>  Pervasives.object_id obj
>>> 
>>> etc.
>>> 
>>> thoughts?
>> 
>> I'm afraid I'm lost.  What's wrong with send, other than its
>> commonness as a name (which is dealt with by __send__)?  If it's too
>> much trouble to explain, that's OK.
>
> so long as we have to rely on objects responding to certain methods certain
> constructs, such as those that meta-programming cut to, can be made difficult
> since the very methods we require to operate can be over-ridden.  this is why
> we have
>
>  __id__
>  __send__
>
> are examples.  by moving the essential methods outside of the object itself 
> an
> into a frozen introspector
>
>  Introspector.object_id obj
>
> we can elimnate this gotcha and this code
>
>  class BlankSlate
>    instance_methods.each{|m| remove_method unless m[/__/]}
>  end
>
> can be reduced (and made more robust) to
>
>  class BlankSlate
>    instance_methods.each{|m| remove_method m}
>  end
>
> make sense?

It seems a bit drastic to flip things around into that less OO style.
I'm not too worried if something like BlankSlate has to jump through a
hoop or two.  In practice, has the name conflict issue with send
actually been much of a problem?


David

-- 
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A. RUBY FOR RAILS by David A. Black (http://www.manning.com/black)
    (See what readers are saying!  http://www.rubypal.com/r4rrevs.pdf)
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