#use strict;
use warnings;
use Term::ReadLine;

my $prompt = "prompt> ";
my $prog = Term::ReadLine->new('Script');
$prog->ornaments(0);

while (defined (my $cmd = $prog->readline($prompt))) {
    chomp $cmd;

    # nothing
    if ($cmd =~ /^\s*$/)        { next }
    # exit
    if ($cmd =~ /^\s*exit\s*$/) { last }

    # execute
    eval "package Sandbox; $cmd";
    warn $@ if $@;

    print "\n"
}

package Sandbox;

sub command {
    print "Special command";
}

sub names {
    my @keys = sort keys %Sandbox::;
    for my $key (@keys) {
        my $glob = \*{"Sandbox::$key"};
        print "\$$key\n" if defined ${*{$glob}{SCALAR}};
        print "\@$key\n" if defined *{$glob}{ARRAY};
        print "\%$key\n" if defined *{$glob}{HASH};
    }
}