use.pl

#!/usr/bin/env perl
use strict;
use warnings;
use utf8;
use 5.12.0;

use Path::Class;

use Getopt::Long;
use Pod::Usage;

my $base_dir = dir('./');
my %modules;

my $process = sub {
    my $entry = shift;
    return unless -f $entry;
    return unless $entry =~ /\.(?:t|p(?:m|l))$/;

    my @lines = $entry->slurp(iomode => '<:utf8');

    for my $line (@lines) {
        my ($module) = $line =~ /^\s*use\s+((?:[A-Z][a-zA-Z0-9]*)(?:::[a-zA-Z][a-zA-Z0-9]*)*)/;
        $modules{$module} = 1 if $module;
    }
};

my $walker;
$walker = sub {
    my ($dir, $sub) = @_;
    for my $entry ($dir->children){
        $walker->($entry, $process) if -d $entry;

        $sub->($entry);
    }
};
$walker->($base_dir, $process);

say for sort keys %modules;

1;