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From: tchrist@convex.COM (Tom Christiansen)
Newsgroups: comp.lang.perl
Subject: Re: pattern match strangeness
Message-ID: <1991Apr11.074119.26116@convex.com>
Date: 11 Apr 91 07:41:19 GMT
References: <1991Apr11.011752.9372@sctc.com>
Sender: newsadm@convex.com (news access account)
Reply-To: tchrist@convex.COM (Tom Christiansen)
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Organization: CONVEX Software Development, Richardson, TX
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Nntp-Posting-Host: pixel.convex.com

From the keyboard of scott@sctc.com (Scott Hammond):
:When $s is set to "", the program below says:
:
:match, s=
:no match
:
:Both matches work for a non-null $s.
:
:Am I doing this wrong?

i think so.

:#!/usr/local/bin/perl
:
:$s = "";
:
:$pat = "/est/";
:
:if ($s =~ eval $pat)

right here is the error: /est/ evals to null or 1, depending on 
what $_ is set to.  you mean:

    if (eval "\$s =~ $pat")

or better:

    $pat = 'est';
    if ($s =~ /$pat/)

:    { print "match, s= $s\n"; }
:
:else
:
:    { print "no match\n"; }
:
:if ($s =~ /est/)
:
:    { print "match, s= $s\n"; }
:
:else
:
:    { print "no match\n"; }

--tom