package Exporter::All;

use strict;
use warnings;

use base qw(Exporter);

our $VERSION = '0.01';

use Carp qw(carp);

# these are not package symbols, but Perl artifacts
my @GLOBAL_SYMBOLS = qw(ISA EXPORT EXPORT_OK EXPORT_TAGS BEGIN );
my %EXCLUDE_LIST;
@EXCLUDE_LIST{@GLOBAL_SYMBOLS} = (1) x @GLOBAL_SYMBOLS;

sub export_all {
    my $self = shift;
    my %args = @_;

    my $package = $args{package} || $self;

    while (my ($k, $v) = each %args) {
        if ($k eq 'export') {
            unless ( $v eq 'CODE' ) {
                carp "should be a subroutine ref";
                next;
            }

            my $export_ref = do { no strict 'refs'; \@{ "${package}::EXPORT" } };
            push @$export_ref, _select_symbols($package, $v);
        } else {
            carp "unknown parameter '$k'";
        }
    }
}

sub _select_symbols {
    my $package = shift;
    my $predicate = shift;

    # iterate the package stash
    my @keys = do { no strict 'refs'; keys %{$package . '::'} };
    return grep { 
                     !$EXCLUDE_LIST{$_} 
                  && do { no strict 'refs'; defined *{"${package}::${_}"}{CODE} } # has CODE slot
                  && $predicate->() 
                } @keys
}

1;

__END__

=head1 NAME

Exporter::All - Export a bunch of symbols easily

=head1 SYNOPSIS

In the code you have symbols to export

    package MyModule;

    use base qw(Export::All);
    MyModule->export_all( export => sub { /^my_/ } );

    # these are automatically exported
    sub my_home { }
    sub my_office { }

In user's code

    use MyModule; # imports all my_ functions

##</code><code>##

package MyConstants;

use base qw(Exporter::All); # must be found in @INC
our @EXPORT;

__PACKAGE__->export_all( export => qr/^[A-Z]+$/ );

our $VERSION = 3; # it doesn't export this!

use constant FOO => 1;
use constant BAR => 2;
use constant BOO => 3;

1;

##</code><code>##

use MyConstants;