Xref: utzoo comp.lang.lisp:3677 comp.lang.scheme:1681
Path: utzoo!utgpu!watserv1!watmath!att!cbnewsc!lgm
From: lgm@cbnewsc.att.com (lawrence.g.mayka)
Newsgroups: comp.lang.lisp,comp.lang.scheme
Subject: Re: Virtues of Lisp syntax
Summary: We "manipulate programs" every day via macros
Message-ID: <1990Sep18.012130.13065@cbnewsc.att.com>
Date: 18 Sep 90 01:21:30 GMT
References: <3368@skye.ed.ac.uk> <SODER.90Sep11141859@basm.nmpcad.se> <20301@well.sf.ca.us>
Followup-To: comp.lang.lisp
Organization: AT&T Bell Laboratories
Lines: 32

In article <20301@well.sf.ca.us>, jjacobs@well.sf.ca.us (Jeffrey Jacobs) writes:
> the "fix" would be propagated even to pending calls.  E.g. if you
> had
> (DEFUN FOO (X Y)
>   expr1
>   expr2
>   ...)
> 
> and expr1 invoked FOO recursively, you could break the execution,
> change expr2 (or TRACE it,  or BREAK it or...), all of the pending
> invocations on the stack were affected.  (You can't do this with
> compiled code).

You can if you use the Set Breakpoint command on a Symbolics
workstation.  TRACE :WHEREIN and ADVISE-WITHIN are also applicable if
'expr2' is a function call.  Or if you mean to change FOO permanently,
recompile it and then reinvoke it at its earliest occurrence on the
stack.

> However, if compilation is the primary development strategy (which it
> is with CL), then the LISP syntax is not particularly useful.  Modern

The great power of Common Lisp's unique syntax extension facilities
(a.k.a. its macro capability) depends on the language's regular
syntax.


	Lawrence G. Mayka
	AT&T Bell Laboratories
	lgm@iexist.att.com

Standard disclaimer.