#!/usr/bin/perl

use warnings;
use strict;
use Gtk2;

## todo: change mnemonic into an accelerator (^D)
## todo: do another one for quitting (^Q)
## bug (fixed by forking): halts on infinite loops :^P

my ($window, $vbox, $ptext, $but, $label);
my $font = 'Monospace 10';
my $perl = '/usr/bin/perl';

sub do_run {
    my $pid;
    my $buf = $ptext->get_buffer;
    local $SIG{'CHLD'} = 'IGNORE';

    warn "fork: $!" and return unless defined ($pid = fork);
    if ($pid) { ## parent
        $ptext->grab_focus;
        return; 
    }

    ## child
    $pid = open my $fd, '|-', $perl, '-t' or die "fork: $!";
    print "\n$perl PID: $pid\n";  ## for easy killing
    print $fd $buf->get_text ($buf->get_bounds, 1);
    close $fd;
    exit;   
}

Gtk2->init;

$window = Gtk2::Window->new ('toplevel');
$vbox   = Gtk2::VBox->new (0, 0); 
$ptext  = Gtk2::TextView->new;
$but    = Gtk2::Button->new;
$label  = Gtk2::Label->new_with_mnemonic ('_Run!');

$but->signal_connect (clicked => \&do_run);
$but->add ($label);
$but->set_size_request (50, 30);

$ptext->set_size_request (50, 20);
$ptext->set_border_width (4);
$ptext->modify_font (Gtk2::Pango::FontDescription->from_string ($font));
$ptext->get_buffer->set_text (<<_DEF_TEXT_);
use warnings;
use strict;
use Data::Dumper;

\$ENV{'PATH'} = \$ENV{'CDPATH'} = '/usr/bin:/bin';

_DEF_TEXT_

$vbox->add ($ptext);
$vbox->pack_end ($but, 0, 0, 0);

$window->signal_connect (destroy => sub { Gtk2->main_quit; });
$window->set_default_size (700, 400);
$window->add ($vbox);
$window->show_all;
Gtk2->main;