#!/usr/bin/perl -w

# a simple text-based menu system

use strict;

my ($menu1, $menu2);
# Sample menus are defined below.  Each menu is an anonymous 
# array. The first element is the title of the menu.  The following 
# elements  are anonymous arrays containing a description of the
# menu item (it will be printed) and a reference to a routine to call 
# should that item be selected.

# The following is a shortcut that can be used in other menus.
my $quit_menu_item = [ "Quit", sub{exit;} ];

$menu1 = [
	     "Title of First Menu",
	     [ "Do Something (first)", \&ds1 ],
	     [ "Second Menu", sub{ &menu( $menu2 )} ],
	     [ "Quit", sub {exit;} ], # We could have used our shortcut.
	 ];

$menu2 = [
	     "Title of Second Menu",
	     [ "Do Something (second)", \&ds2 ],
	     [ "First Menu", sub{ &menu( $menu1 )} ],
	     $quit_menu_item, # This is our shortcut.
	 ];

##### The menu routine itself. #####
sub menu {
    my $m = shift;
    my $choice;
    while (1) {
	print "$m->[0]:\n";
	print map { "\t$_. $m->[$_][0]\n" } (1..$#$m);
	print "> ";
	chomp ($choice = <>);
	last if ( ($choice > 0) && ($choice <= $#$m ));
	print "You chose '$choice'.  That is not a valid option.\n\n";
    }
    &{$m->[$choice][1]};
}

# Do something 1
sub ds1 {
    print "\nIn ds1\n\n";
    &menu($menu1);
}

# Do something 2
sub ds2 {
    print "\nIn ds2\n\n";
    &menu($menu2);
}

## TEST
&menu($menu1);