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From: allbery@NCoast.ORG (Brandon S. Allbery KB8JRR/AA)
Newsgroups: comp.lang.perl
Subject: Re: Perl code to test for valid reg-exp?
Message-ID: <1991May2.232320.12037@NCoast.ORG>
Date: 2 May 91 23:23:20 GMT
References: <9105021740.AA06244@peanut.crl.dec.com>
Reply-To: allbery@ncoast.ORG (Brandon S. Allbery KB8JRR/AA)
Followup-To: comp.lang.perl
Organization: North Coast Public Access Un*x (ncoast)
Lines: 23

As quoted from <9105021740.AA06244@peanut.crl.dec.com> by jmiller@crl.dec.com:
+---------------
| Has anyone got a short (preferably) piece of Perl code to test a
| string to see whether or not it is a valid regular expression for use
| in Perl?  I've written a program that allows users to type a string
| and then uses that to match against a data base; unfortunately the
| program blows up if the user types in an invalid string!
+---------------

Well, the trivial way is:

	eval '/$trial_regexp/; 1' || print "Invalid regexp: $@";

I.e. let the "eval" run it.  If the eval bombs, it will return 0, else 1
(because we told it to).  The error message that would have splattered onto
the terminal is in $@.

++Brandon
-- 
Me: Brandon S. Allbery			  Ham: KB8JRR/AA  10m,6m,2m,220,440,1.2
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