source: vendor/perl/5.8.8/lib/autouse.pm

package autouse;

#use strict;            # debugging only
use 5.003_90;           # ->can, for my $var

$autouse::VERSION = '1.05';

$autouse::DEBUG ||= 0;

sub vet_import ($);

sub croak {
    require Carp;
    Carp::croak(@_);
}

sub import {
    my $class = @_ ? shift : 'autouse';
    croak "usage: use $class MODULE [,SUBS...]" unless @_;
    my $module = shift;

    (my $pm = $module) =~ s{::}{/}g;
    $pm .= '.pm';
    if (exists $INC{$pm}) {
        vet_import $module;
        local $Exporter::ExportLevel = $Exporter::ExportLevel + 1;
        # $Exporter::Verbose = 1;
        return $module->import(map { (my $f = $_) =~ s/\(.*?\)$//; $f } @_);
    }

    # It is not loaded: need to do real work.
    my $callpkg = caller(0);
    print "autouse called from $callpkg\n" if $autouse::DEBUG;

    my $index;
    for my $f (@_) {
        my $proto;
        $proto = $1 if (my $func = $f) =~ s/\((.*)\)$//;

        my $closure_import_func = $func;        # Full name
        my $closure_func = $func;               # Name inside package
        my $index = rindex($func, '::');
        if ($index == -1) {
            $closure_import_func = "${callpkg}::$func";
        } else {
            $closure_func = substr $func, $index + 2;
            croak "autouse into different package attempted"
                unless substr($func, 0, $index) eq $module;
        }

        my $load_sub = sub {
            unless ($INC{$pm}) {
                require $pm;