#!/usr/bin/perl

# By Sean Murphy
# E-Mail Syntax Checker
#
# This is a simple script that will
# check the syntax of an email address
# and spit back whether the address is
# syntactically correct or not. This
# is my first post to the Craft node.

#mmmm...marshmallowey goodness...
$atom = '[^()<>@,;:\".\[\] \000-\037\177]+';
$quoted = '"(?:[^"\\\n]|\\.)*"';
$word = "(?:$atom|$quoted)";
$localpart = "$word(?:\.$word)*";
$subdomain = "(?:$atom|\\[(?:[^\\[\\]\\\\\\r]|\\.)*\\])";
$domain = "$subdomain(?:\.$subdomain)*";
$addrspec = "$localpart\@$domain";
$route = "(?:\@$domain)+:";
$routeaddr = "<$route?$addrspec>";
$mailbox = "(?:$addrspec|$word+$routeaddr)";
$group = "$word+:(?:$mailbox(?:,+$mailbox)*)?;";
$address = "$mailbox|$group";

sub addr {
local($_) = @_;
1 while s/\((?:[^()]|\\[()])*?[^\\]\)/ /g;
/$address/o;
}

if (@ARGV > 0) {
foreach (@ARGV) { print "$_ is ", addr($_) ? "" : "not ", "valid\n"; }
} else {
while (<>) { chop; print "$_ is ", addr($_) ? "" : "not ", "valid\n"; }
}