Path: utzoo!dciem!nrcaer!scs!spl1!laidbak!att!ihnp4!ucbvax!renoir.Berkeley.EDU!cox
From: cox@renoir.Berkeley.EDU (Charles A. Cox)
Newsgroups: comp.lang.lisp
Subject: Re: What's the value of lexical scoping?
Message-ID: <24531@ucbvax.BERKELEY.EDU>
Date: 5 Jun 88 00:54:55 GMT
Article-I.D.: ucbvax.24531
References: <24508@ucbvax.BERKELEY.EDU>
Sender: usenet@ucbvax.BERKELEY.EDU
Reply-To: cox@renoir.Berkeley.EDU.UUCP (Charles A. Cox)
Organization: University of California, Berkeley
Lines: 22

In article <24508@ucbvax.BERKELEY.EDU> mkent@dewey.soe.berkeley.edu (Marty Kent) writes:
>  [...] In fact, with Allegro Common Lisp the situation
>is even worse, because the compiler doesn't save the names of locals in
>the stack frames, which makes it pretty much impossible to scan at runtime
>to resolve a name-based reference. 

I am more familiar with Allegro Common Lisp that runs on Unix
machines, but I am told that with the MAC-OS Allegro, beginning with
version 1.2, setting the *SAVE-DEFINITIONS* compiler flag will cause
the parameter names and values to be printed in a backtrace.  This
will aid in debugging.

In the UNIX version of Allegro Common Lisp, there is a variable called
COMP:SAVE-LOCAL-NAMES-SWITCH which is bound to a function.  When this
user redefinable function returns T, the compiler will save the
names of all the local variables.  These variable are then accessible
by name using the `:LOCAL' top level command.

Hope this helps.

	Charley Cox
	cox@renoir.Berkeley.EDU