From: Gavin Sinclair <gsinclair@...>
Date: 2003-11-28T12:59:02+09:00
Subject: Re: Controlled block variables

From T. Onama:
>> In short, the message-passing paradigm is paramount in Ruby.  You may
>> say that 'foo.aproc is a Proc object', but the reality is that
>> 'foo.aproc' is the result of sending the message 'aproc' to 'foo'.
>> Nothing more, nothing less.  And there are good reasons why that won't
>> change.  Making parens optional is just a superficial reason.
>
> Thanks Gavin. I read it over. And I certainly understand the
> distinction. To  sum up: foo.aproc is sending a message called 'aproc'
> to the object 'foo'.  But it's still returning an Proc object. Yes?

Maybe.  It could return a String, nil, a FroBoz, anything really.

> There's probably something  obvious that I'm just overlooking here, but
> I don't see the reason why Ruby  can't infer the #call message when a
> Proc object (or Method object for that  matter) is returned given with
> parens.
>
>   aproc()   # -> aproc.call()
>
> in a fashion similiar to how it can infer self as a reciever.

aproc() calls the method 'aproc' (sends the message :aproc) with no
arguments.  It can't add a magic :call message in there.

Maybe - I'm not sure - you're under the misunderstanding that, or maybe
you're proposing that the following should occur:

  class Example
    def ameth(x)
      x + 1
    end
  end

  e = Example.new

  e.ameth    # returns Proc
             # return value equiv. to proc { |x| x + 1 }

  # Instead of
  # e.ameth       -> ArgumentError: 0 for 1

This is the "methods as first class objects" wish that Python implements. 
Is that what you're proposing?  If so, I missed it or misunderstood it in
previous messages.

I sympathise with the wish that methods be first class, and that you can
pass them around, but when I red Jim Weirich's article
(http://onestepback.org/index.cgi/Tech/Ruby/PythonAndRuby.rdoc) that door
forever closed in my mind.

If you can clear up the misunderstandings I have about where you're coming
from, I'd like to hear your proposals.

Cheers,
Gavin