Message from discussion Implementation Favoritism, a question of Lisp mindsets
From: Ed L Cashin <ecas...@uga.edu>
Subject: Re: Implementation Favoritism, a question of Lisp mindsets
Date: Sat, 03 May 2003 18:23:53 -0400
User-Agent: Gnus/5.090014 (Oort Gnus v0.14) Emacs/21.2
Content-Type: text/plain; charset=us-ascii
X-Cache: nntpcache 2.4.0b5 (see http://www.nntpcache.org/)
Mark Conrad <nos...@iam.invalid> writes:
> In article <878ytnyjvh....@cs.uga.edu>, Ed L Cashin <ecas...@uga.edu>
>> Pascal Costanza <costa...@web.de> writes:
>> > See for example the entry for binding in the glossary section of the
>> > HyperSpec:
>> > binding n. an association between a name and that which the name
>> > denotes. ``A lexical binding is a lexical association between a name and
>> > its value.''
>> Thank you! I was growing worried after two people suggested that a
>> binding is a bucket where a value can be kept. Then the word itself
>> wouldn't relate to its meaning. Nothing is being bound in the concept
>> of "a location where a value may be kept".
> FWIW, those same suggestions that a binding is a location puzzled and
> confused me also, so you are not alone.
I don't think I was confused, just distressed. To equate "binding" to
"location" is confusion. So when Erann Gat says,
(let ((x 1)) ; Establish a binding (i.e. a memory location) for X.
... it's misleading. There are distinct things happenning: there's a
memory location allocated, and there's a name, "x", associated with
that memory location. The binding is the relationship between the
name and the memory location that allows you to access the memory
location by using the name.
There's no advantage to collapsing the concepts of location and
binding. Calling a memory location an "object" or just a memory
location is more accurate and more discriptive.
> I see that idea of a binding being a location in a few of my Lisp
> books also.
Yeah, I think that's an unhelpful collapse of ideas, where the useful
distinction between memory objects, names, and bindings is being lost.
In a forum like this, I expect a higher standard of precision. After
all, after newbies read confusing books, this is where they'll come.
--Ed L Cashin PGP public key: http://noserose.net/e/pgp/