Having just read the section in Damian's Object Oriented Perl book about the regular use of qr, this looked like a good chance to try it out. That is, with qr, you are creating a reference to a regular expression which you can store in a scalar variable. When that scalar variable is used in a regex later on, the complilation work to prepare the referenced regex doesn't have to be repeated each time through your loop, avoiding a good amount of regex overhead.

Here's the snippet again with some tweaks to your example. Note, whenever I store a reference in a scalar, I like to suffix the identifier with _Xr, where X stands for the kind of thing that's supposed to be referenced (in this case r for "regex") and the closing r indicates that the scalar is supposed to hold a reference.

#!/usr/local/bin/perl -w
use strict;

my @names = ("John?", "Paul", "George", "Rin.go");

my $regexStr
    = "^static\\s+\\w+\\s+("
                # Thanks moritz!
    . (join "|",map quotemeta,@names)
    . ")\\W.*";
print "$regexStr\n\n";

my $regexStr_rr = qr{$regexStr}i; # or "cloister" the 'i' in $regexStr

while(<DATA>) {
    chomp;

    my ( $hit )
        = $_ =~ /$regexStr_rr/;
  
    if ($hit) {
        print "Beatle method \"$hit\" found on this line: $_\n";
    }
    else {
        print "No Beatle method found on this line: $_\n";
    }
}

__DATA__
static int lars(...);
static bool george(...);
static int thom(...);

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In reply to Re^2: RegExp to Search All Array Members? by ff
in thread RegExp to Search All Array Members? by shoness

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