escape_perl_regular_expression.txt

#!/usr/bin/perl
# script to replace regular expression content with "case insensitive regexp"
# Copyright (C) Neptune Web, Inc.

# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.

# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.

# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

$s = '';
while (<STDIN>) {
$s .= $_;
} 

print removeWhiteSpaceAndEscapeRegexp($s);


sub removeWhiteSpaceAndEscapeRegexp() {
    my ($ins) = @_;
# remove all regexp meaningful characters.
    $ins =~ s/([\$\|\*\?\]\[\^\/\+\.\"\(\)])/\\$1/isg;
    # add whitespace independence, but only after weird (regular expression) chars have been removed.
    $ins =~ s/\s+/\\s*/isg;
    return $ins;
}