##### main.pl
#! /usr/bin/env perl

use lib q<.>;

use warnings;
use strict;
use utf8;
use feature qw<say>;

use MyFuncs qw<add minus multi divide>;

say add(12, 34);
say minus(12, 34);
say multi(12, 34);
say divide(12, 34);

# say "\n";

# for my $key (sort keys %::) {
#   say "${key}=>", $::{$key};
# }

exit(0);

##### MyFuncs.pm
package MyFuncs;

use 5.006;
use strict;
use warnings;

use MyExporter qw<import>;

our @EXPORT_OK = qw<add minus multi divide>;

sub add {
    my ($a, $b) = @_;
    $a + $b;
}

sub minus {
    my ($a, $b) = @_;
    $a - $b;
}

sub multi {
    my ($a, $b) = @_;
    $a * $b;
}

sub divide {
    my ($a, $b) = @_;
    die "Can't divide by $b" if $b == 0;
    $a / $b;
}

1; # End of MyFuncs

##### MyExporter.pm
package MyExporter;

use 5.006;
use strict;
use warnings;
use feature qw<say>;
use List::Util qw<any>;

sub import {
  my ($pack, @funcs) = @_;#MyExporter @funcs
  my ($c_pack) = caller;#MyFuncs

  if (any{$_ eq 'import'} @funcs) {
    no strict qw<refs>;

    *{"${c_pack}::import"} = \&{"${pack}::myImport"};
  }
}

sub myImport {
  my ($pack, @funcs) = @_;#MyFuncs @funcs
  my ($c_pack) = caller;#main

  {
    no strict qw<refs>;

    if (@{"${pack}::EXPORT_OK"}) {
      for my $func (@funcs) {
        if (any{$_ eq $func} @{"${pack}::EXPORT_OK"}) {
          *{"${c_pack}::${func}"} = \&{"${pack}::${func}"};
        }else {
          die "Can't find \"$func\" in the export list";
        }
      }
    }
  }
}

1; # End of MyExporter