finding the match boundaries in a Perl regex

Perl FAQ
"Since Perl 5.6.1 the special variables @- and @+ can functionally replace $`, $& and $'. These arrays contain pointers to the beginning and end of each match (see perlvar for the full story), so they give you essentially the same information, but without the risk of excessive string copying."


Regex-Related Special Variables

Perl has a host of special variables that get filled after every m// or s/// regex match. $1, $2, $3, etc. hold the backreferences. $+ holds the last (highest-numbered) backreference. $& (dollar ampersand) holds the entire regex match.

@- is an array of match-start indices into the string. $-[0] holds the start of the entire regex match, $-[1] the start of the first backreference, etc. Likewise, @+ holds match-end indices (ends, not lengths).

$' (dollar followed by an apostrophe or single quote) holds the part of the string after (to the right of) the regex match. $` (dollar backtick) holds the part of the string before (to the left of) the regex match. Using these variables is not recommended in scripts when performance matters, as it causes Perl to slow down all regex matches in your entire script.

All these variables are read-only, and persist until the next regex match is attempted. They are dynamically scoped, as if they had an implicit 'local' at the start of the enclosing scope. Thus if you do a regex match, and call a sub that does a regex match, when that sub returns, your variables are still set as they were for the first match.


if ($lineCopy =~ /$joinedColumns/g) {

my $start = @+[0]; # match start index stored in position 0 in the array

print "MATCH: Found '$&'. lineCopy= " . $lineCopy . "\n";

print "MATCH: atminux = @- atplus= @+\n";
# print "MATCH: Next attempt at character " . pos($lineCopy) + 1 . "\n";
}
else {
print "NO MATCH: line = $lineCopy joinedColumns = $joinedColumns\n";
}

MATCH: Found 'attachments,grinder attachments'. lineCopy= tools,attachments,grinder attachments
MATCH: atminux = 6 atplus= 37
NO MATCH: line = tools,attachments,hammer \& hammer drill attachments joinedColumns = attachments,hammer\ \&\ hammer\ drill\ attachments
MATCH: Found 'attachments,jig saw attachments'. lineCopy= tools,attachments,jig saw attachments
MATCH: atminux = 6 atplus= 37
MATCH: Found 'attachments,metal case'. lineCopy= tools,attachments,metal case
MATCH: atminux = 6 atplus= 28
MATCH: Found 'attachments,miter saw attachments'. lineCopy= tools,attachments,miter saw attachments
MATCH: atminux = 6 atplus= 39
MATCH: Found 'attachments,nibbler attachments'. lineCopy= tools,attachments,nibbler attachments
MATCH: atminux = 6 atplus= 37

TRAC installation including trac HTML form based authentication

trac-admin /home/trac/yo_web_services initenv
chown -R apache.apache /home/svn/yo_web_services
chown -R apache.apache /home/trac/yo_web_services

vim /etc/httpd/conf.d/trac.conf
>>

SetHandler mod_python
PythonHandler trac.web.modpython_frontend
PythonOption TracEnv /home/trac/yo_web_services
PythonOption TracUriRoot /trac/yo_web_services



AuthType Basic
AuthName "trac"
AuthUserFile /home/trac/trac.htpasswd
# comment the next line if using HTML form based login using the trac plugins
# per the trac-hacks page
# Require valid-user


<< touch /home/trac/yo_web_services.htpasswd #Add users to password file htpasswd -m /home/trac/yo_web_services.htpasswd
trac-admin /home/trac/yo_web_services permission add TRAC_ADMIN

service httpd restart

Add the plugins from this page
http://trac-hacks.org/wiki/AccountManagerPlugin

Mac OSX X11 fix

make sure /usr/X11R6 is empty
cd /usr
ln -s X11R6 X11
now the dylibs will be found...