#!/usr/bin/perl

use strict;
use warnings;
use Term::ANSIColor qw/:constants/;

my $input = shift;
die "Usage: $0 <regexp> [files...]\n" if not defined $input;

my $regexp = eval { qr/$input/o };
die "Pattern error: $@\n" if $@;

while (my $line = <>) {
	chomp $line;
	if ($line =~ m/$regexp/) {
		for my $i (0 .. $#+) {
			my ($start, $stop) = ($-[$i], $+[$i]);
			print q/$/
			      , $i ? $i : q/&/
			      , q/: /
			      , substr($line, 0, $start)
			      , BOLD,
			      , ($stop - $start > 0) ?
					(RED, substr($line, $start
						     , $stop - $start))
					: (BLUE, q/|/)
			      , RESET
			      , substr($line, $stop)
			      , qq/\n/;
		}
	}
}