lgrep

#!/usr/bin/perl -w

use strict;
# lgrep: likeness-grep or l33t-grep
# Attempt to match things that may have been obfuscated by l33tspeak,
#	possibly by marketers trying to avoid filters
# Note that this will tend to move towards letters, not away from it, so
#	placing numbers or other nonnumerics in the search string is not
#	recommended. It also lowercases everything for broader matching.

main(@ARGV);

############################

sub main
{
my @args = @_;
if(@args < 2)
	{usage();}
my $pattern = lc shift @args;
foreach my $file (@args)
	{
	open(THISF, $file) || die "ERROR: Could not open [$file]:$!\n";
	while(my $thisl = readline(THISF) )
		{
		my $match = 0;
		$thisl =~ tr/\r\n\f//d;
		my @parsings = interpret_line($thisl);
		foreach my $parsing (@parsings)
			{ # tempting to use grep(), but we want short-circuit
			if($parsing =~ /$pattern/)
				{$match++;last;}
			}
		if($match) {print "$file: $thisl\n"}
		}
	close(THISF);
	}
}

sub interpret_line
{ # Interpret a line, return all plausible interpretations of it in a list
my ($inl) = @_;

$inl = lc($inl);
my @returner;

$inl =~ tr/150/iso/;
$inl =~ tr/3/e/;
push(@returner, $inl);

return @returner;
}


sub usage
{
die "Usage: lgrep PATTERN FILE [FILES..]\n";
}