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From: merlyn@iwarp.intel.com (Randal Schwartz)
Newsgroups: comp.lang.perl
Subject: Re: Parens in a reg exp
Message-ID: <1990Sep13.013737.10897@iwarp.intel.com>
Date: 13 Sep 90 01:37:37 GMT
References: <MIKE.MCMANUS.90Sep12091652@mustang.FtCollins.NCR.com>
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Reply-To: merlyn@iwarp.intel.com (Randal Schwartz)
Distribution: comp
Organization: Stonehenge; netaccess via Intel, Beaverton, Oregon, USA
Lines: 55
In-Reply-To: Mike.McManus@FtCollins.NCR.com (Mike McManus)

In article <MIKE.MCMANUS.90Sep12091652@mustang.FtCollins.NCR.com>, Mike.McManus@FtCollins (Mike McManus) writes:
| 
| I'm reading tokens in from a file and doing compares on the token, sort of
| like:
| 
| @toklist = ("VDD", "GND", IN", "OUT", "INOUT");
| 
| while(<>) {
|     if( do IS_TERM()) {
|     ...
|     }
| }
| 
| sub IS_TERM() {
|     $token = (split)[1];
|     if( join( " ", @tklist) !~ /$token/) {return(0);}
|     foreach $i (@toklist) {
|         if( $i eq $token) {
|             .... 
|             return(1);
|         }
|     }
|     return(0);
| }

Shoot.  You're doin' it the hard way.  Give the task to Perl in the
form of a regex that matches *everything* you wanna lookfor in one
fell swoop...


################################################## snip here
@toklist = ("VDD", "GND", "IN", "OUT", "INOUT");

grep(s/\W/\\\&/g,@toklist); # de magic-ize toklist

eval 'sub is_token { $_[0] =~ /(' . join('|',@toklist) . ')/; }';
# add ^ and $ here if you want anchored matches (I think you do)

#testing one two three...
for ('aaa','bbb','VDD','ccc','ddd') {
	print
		"$_ ",
		&is_token($_) ? "IS" : "isn't",
		" a token\n";
}
################################################## snip

There.  OK?

print "Just another token Perl hacker," # :-)
-- 
/=Randal L. Schwartz, Stonehenge Consulting Services (503)777-0095 ==========\
| on contract to Intel's iWarp project, Beaverton, Oregon, USA, Sol III      |
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