Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!clyde.concordia.ca!uunet!cs.utexas.edu!farquhar
From: farquhar@cs.utexas.edu (Adam Farquhar)
Newsgroups: comp.lang.lisp
Subject: Re: READ and upper/lower case symbol print names
Summary: *print-case* may do it, but has a suprising characteristic
Message-ID: <7390@cs.utexas.edu>
Date: 19 Dec 89 16:32:06 GMT
References: <23295@brunix.UUCP>
Organization: U. Texas CS Dept., Austin, Texas
Lines: 24

In article <23295@brunix.UUCP> mj@cs.brown.edu (Mark Johnson) writes:
>Is there an easy way to modify the lisp READ function so that
>it does not always convert lower case letters to upper case
>in symbol names?

The variable *print-case* may provide the functionality that you need.
If *print-case* is set to :downcase, rather than it's default value of
:upcase, all symbols will be printed out in lowercase.  This only
affects the printing, however, and does not alter the name of any
symbols.  As a colleague of mine, David Throop, recently pointed out
to me, this may result in some suprising behavior when converting from
strings to symbols.  I.e. 
	(setq *print-case* :downcase) => :downcase
	(setq x 'foo) => foo
	(string x) => "FOO"
	(format nil "~a" x) => "foo"
	(intern "foo") => |foo|
thus	(eq (intern "foo") x) => nil
and     (eq (intern "FOO") x) => t
and     (eq (intern (prin1-to-string 'foo)) 'foo) => nil

This can give rise to some difficult to find bugs.  I would tend to
lowercase output with either string-downcase or (format t "~(~a~)").

Adam Farquhar.