From: Just Another Victim of the Ambient Morality <ihatespam@...>
Date: 2006-08-01T22:20:06+09:00
Subject: Re: I thought this was the one that worked?


"Chad Perrin" <perrin@apotheon.com> wrote in message 
news:20060801103834.GB28710@apotheon.com...
> On Tue, Aug 01, 2006 at 06:50:09PM +0900, Just Another Victim of the 
> Ambient Morality wrote:
>>
>>     This seriously sounds like an "if a tree falls in the forest, does it
>> make a sound?" kind of situation.  In other words, it's a semantic
>> argument...
>
> Okay, let's translate that question into the terms we're actually
> discussing.
>
>  1. If a tree falls in the forest, and there's no one around to hear
>  it, does it still make a sound?
>
>  2. If a lambda has the ability to access its context, but there isn't
>  any context to access, is it still a closure?

    How about this:

3. If a lambda has the ability to access its context and nothing's around to 
use it, does it still make a closure?

    I think 3 is a better characterization than 2.  Here's some code to 
demonstrate:


variable = 2  # this is the context

[1, 2, 3].each do |i|
    # it sounds as if you think this is the "context"
    puts i + variable

    # either way, we're using the context so
    # we agree that this is a closure
end

[4, 5, 6].each do |i|
    # a context exists here since we
    # have access to "variable"
    puts i

    # but we don't use it.
    # are we still a closure?
end


> I'm beginning to think the question of whether it's actually a closure
> really IS a question for a programming koan, after all.  If so, I'm glad
> we've at least narrowed the discussion down to this point at last.

    I agree that we have finally narrowed down the discussion.  This might 
have happened sooner if I had actually followed the thread...


> It'd be pretty neat to be responsible for the creation of a new
> programming koan, anyway.  I'm going to go add this to my sig rotation
> right now.

    Ah, it's over-rated...
    Is a loop a loop if it only loops once?
    Does a parameter exist if we don't actually access it?

    Not to be insulting but there's a part of me that thinks that you came 
up with this distinction to hide the (embarrassing?) fact that you didn't 
know that all blocks were closures...