#!/usr/bin/perl -w

# In my day job, we use PHP and I wanted to find all 
# the variables in a source tree that were used only
# once, so I whipped this out.

use strict;
use File::Find;

find( \&handler, "." );

my %byfile;
my %all;

my @listers = keys %byfile;

# Comment this if you want all vars, not just those used once
@listers = grep { $all{$_} <= 1 } @listers;

for my $var ( sort @listers ) {
    print "$var\n";
    my $files = $byfile{$var};
    for my $file ( sort keys %$files ) {
        printf( "  %5d %s\n", $files->{$file}, $file );
    } # for file
} # for var

sub handler {
    if ( -d ) {
        $File::Find::prune = 1 if /^(CVS|pl)$/;
        return;
    }

    return unless /\.(html?|php|inc)$/;

    open( IN, $_ ) or die "Can't open $_: $!";
    while (<IN>) {
        s[//.+][]; # ignore comments (kinda)
        while ( /(\$[a-z_][a-z0-9_]*)/g ) {
            my $var = $1;
            ++$byfile{$var}{$File::Find::name};
            ++$all{$var};
        } # while grep
    } # while <IN>
    close IN;
}