From: Chad Perrin <perrin@...>
Date: 2006-08-02T06:14:44+09:00
Subject: Re: I thought this was the one that worked?

On Wed, Aug 02, 2006 at 06:00:28AM +0900, Marshall T. Vandegrift wrote:
> Chad Perrin <perrin@apotheon.com> writes:
> 
> > On Wed, Aug 02, 2006 at 12:45:46AM +0900, Marshall T. Vandegrift wrote:
> >> 
> >> I'm joining the party late, but try this example:
> >
> > Why?  Why should we keep trying unnecessarily complex examples that
> > introduce a bunch of variables (in the statistical study sense of the
> > term) that are not strictly relevant to the point under consideration?
> 
> In the hope that eventually an example might satisfy your all your
> criteria and demonstrate why Ruby blocks are closures.  And at the

The equivalent of line noise, distracting from the actual point of
discussion, doesn't help.


> 
> > That's not very useful.  The Wikipedia "description" (it's not a
> > dictionary, and as such doesn't strictly speaking aim to "define" the
> > terms contained within it) is, for purposes of this discussion,
> > nigh-uselessly broad and lacking in coherent detail.
> 
> How's this one from the Free On-line Dictionary of Computing?:
> 
>     closure
> 
>     1. <programming> In a reduction system, a closure is a data
>        structure that holds an expression and an environment of
>        variable bindings in which that expression is to be
>        evaluated. The variables may be local or global. Closures are
>        used to represent unevaluated expressions when implementing
>        functional programming languages with lazy evaluation. In a
>        real implementation, both expression and environment are
>        represented by pointers. [1]


It, like basically every other definition I've run across, doesn't
actually address the salient points.  May I please speak with David
again?  He at least was discussing something precise enough to be
on-topic for the point of contention.


> 
> > Only if you accept a description of a closure as a definition.  As I
> > implied elsewhere, however, "has four limbs" may be an accurate
> > description of a human, but the fact "dog" fits that description doesn't
> > make it a human.
> 
> Oh, I see the problem: metaphysically you're more of an essentialist
> and I'm more of a functionalist.  Alas, this can only end in tears. ;-)

I'm also more of a prescriptivist than a descriptivist in natural
linguistic terms.  I like precision in my understanding when discussing
technical topics.  "It shares some characteristics with something
someone once called a closure!" isn't enough for me.

-- 
CCD CopyWrite Chad Perrin [ http://ccd.apotheon.org ]
"The ability to quote is a serviceable
substitute for wit." - W. Somerset Maugham