Path: utzoo!attcan!uunet!aplcen!haven!mimsy!chris
From: chris@mimsy.umd.edu (Chris Torek)
Newsgroups: comp.lang.c
Subject: Re: Using Lex (and Yacc) on a string.
Message-ID: <26012@mimsy.umd.edu>
Date: 14 Aug 90 11:58:30 GMT
References: <1990Aug10.012927.5558@basho.uucp> <174@ittc.wec.com> <25996@mimsy.umd.edu>
Organization: U of Maryland, Dept. of Computer Science, Coll. Pk., MD 20742
Lines: 25

In article <25996@mimsy.umd.edu> I suggested:
>#define unput(c) (mystring--)

(and then eventually)

>#define unput(c) ((c) ? mystr-- : 0)

The first of these will fail because lex uses unput as

	unput(*--yylastch)

and

	unput(*yylastch--)

Thanks to Brad White for noticing this error.  The first one should
be `#define unput(c) ((c), mystring--)'.

(This is what I get for making changes to lex things based on theoretical
arguments without checking to see whether lex uses good programming
practises :-) .)
-- 
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7163)
Domain:	chris@cs.umd.edu	Path:	uunet!mimsy!chris
	(New campus phone system, active sometime soon: +1 301 405 2750)