Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!ucsd!chem.ucsd.edu!tps
From: tps@chem.ucsd.edu (Tom Stockfisch)
Newsgroups: comp.lang.c
Subject: Re: regex for C comments
Message-ID: <502@chem.ucsd.EDU>
Date: 12 Jul 89 01:07:26 GMT
References: <19365@paris.ics.uci.edu>
Reply-To: tps@chem.ucsd.edu (Tom Stockfisch)
Distribution: na
Organization: Chemistry Dept, UC San Diego
Lines: 23

In article <19365@paris.ics.uci.edu> schmidt@zola.ics.uci.edu (Doug Schmidt) writes:
>In their book ``Introduction to Compiler Construction with UNIX,''
>Schreiner and Friedman provide the following LEX regular expression
>for recognizing C comments:
>"/*""/"*([^*/]|[^*]"/"|"*"[^/])*"*"*"*/"

This expression fails on each of the following:

	/*****//hello world */

	/* hello /* /* world */

So, who has the shortest single LEX expression that correctly
matches C comments --
ignoring string and character constants,
and disallowing start conditions?

Mine is

	"/*"\/*([^/]|{[^*/]\/+})*"*/"
-- 

|| Tom Stockfisch, UCSD Chemistry	tps@chem.ucsd.edu