Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sdd.hp.com!mips!decwrl!ucbvax!iwarp.intel.com!news
From: merlyn@iwarp.intel.com (Randal Schwartz)
Newsgroups: comp.lang.perl
Subject: Re: Is this a Bug?
Summary: No. :-)
Keywords: perl bug
Message-ID: <1990Oct5.183751.9602@iwarp.intel.com>
Date: 5 Oct 90 18:37:51 GMT
References: <9134@cg-atla.UUCP>
Sender: news@iwarp.intel.com
Reply-To: merlyn@iwarp.intel.com (Randal Schwartz)
Distribution: na
Organization: Stonehenge; netaccess via Intel, Beaverton, Oregon, USA
Lines: 38
In-Reply-To: white@cg-atla.UUCP (Frank )

In article <9134@cg-atla.UUCP>, white@cg-atla (Frank ) writes:
| 
| 	I am using 'perl' PL18. Running the following script
| causes "WORD WITH PARENS" to be printed. What's the difference?
| ----------------- cut here -------------------------------------------
| #!/usr/local/bin/perl
| 
| $_ = "This line contains a\nword beginning a line";
| if ( /^word/ ) {
| 	print "WORD NO PARENS\n";
| } elsif ( /^(word)/ ) {
| 	print "WORD WITH PARENS\n";	# I get this message !!
| }

Quoting from perl(1):

     By default, the ^ character is only guaranteed to  match  at
     the beginning of the string, the $ character only at the end
     (or before the newline at the end)  and  perl  does  certain
     optimizations  with  the assumption that the string contains
     only one line.  The behavior of ^ and $ on embedded newlines
                     ============================================
     will  be  inconsistent.   You  may, however, wish to treat a
     =======================
     string as a multi-line buffer, such that the  ^  will  match
     after any newline within the string, and $ will match before
     any newline.  At the cost of a little more overhead, you can
     do this by setting the variable $* to 1.  Setting it back to
     0 makes perl revert to its old behavior.

The "Fine" Manual says all.

++$*; $_ = "\nJust another Perl hacker,"; /^J.*/; print $&
-- 
/=Randal L. Schwartz, Stonehenge Consulting Services (503)777-0095 ==========\
| on contract to Intel's iWarp project, Beaverton, Oregon, USA, Sol III      |
| merlyn@iwarp.intel.com ...!any-MX-mailer-like-uunet!iwarp.intel.com!merlyn |
\=Cute Quote: "Welcome to Portland, Oregon, home of the California Raisins!"=/