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From: edelson@pooh.ils.nwu.edu (Daniel Choy Edelson)
Newsgroups: comp.lang.lisp
Subject: Re: Matching Parens (was Virtues of LISP Syntax?)
Message-ID: <1950@anaxagoras.ils.nwu.edu>
Date: 29 Sep 90 15:08:46 GMT
References: <12558@accuvax.nwu.edu>
Sender: news@anaxagoras.ils.nwu.edu
Reply-To: edelson@ils.nwu.edu (Daniel Choy Edelson)
Organization: Inst. for the Learning Sciences, Northwestern Univ, Evanston IL
Lines: 42

In article <12558@accuvax.nwu.edu> lynch@aristotle.ils.nwu.edu (Richard Lynch) writes:

>That's why I always follow these rules:
>
>A closing parenthesis can only appear:
>  A.  In the same line as the open parenthesis.
>  B.  In the same column as the open parenthesis.
>

>The expense of a lot of lines with just right parens is worth the benifit of
>minimal debugging time to me.

>"TANSTAAFL" Rich lynch@aristotle.ils.nwu.edu

I've thought about this for a while, and I can't see any benefit to
it.  

It doesn't help you debug, because if there's a parenthesis problem
then you can't count any of the parens being in the correct column
anymore, and you have to go to the same trouble as normal to find
which right paren is missing.

As others have pointed out, I can't see how it helps at coding time,
because the formatters and electric-paren features of emacs-like code
show you which paren you're matching without you needing to space over
to the appropriate column.

Most important, I think that an experienced lisp programmer spends
very little time debugging parenthesis errors, no matter where he or
she puts the right parens and that the time and space spent in
following these rules is time lost not gained.

I think that a novice lisp programmer would be better served in
learning to use formatters and paren balancers than in taking time to
learn rules like these. 


--
---------
Danny Edelson   	Institute for the Learning Sciences
edelson@ils.nwu.edu 	     Northwestern University
(708) 491-3500                 Evanston, IL 60201