#     THE CODE #############################

#!/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 )} ],
         [ "Continue", sub {}],
         [ "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]};
}

print "a\n";

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

print "b\n";

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

print "c\n";

## TEST
&menu($menu1);

print "Continue after menu call \n";







#     THE CONSOLE #############################

a
b
c
Title of First Menu:
	1. Do Something (first)
	2. Second Menu
	3. Continue
	4. Quit
> 1

In ds1

Title of First Menu:
	1. Do Something (first)
	2. Second Menu
	3. Continue
	4. Quit
> 1

In ds1

Title of First Menu:
	1. Do Something (first)
	2. Second Menu
	3. Continue
	4. Quit
> 2
Title of Second Menu:
	1. Do Something (second)
	2. First Menu
	3. Quit
> 1

In ds2

Title of Second Menu:
	1. Do Something (second)
	2. First Menu
	3. Quit
> 1

In ds2

Title of Second Menu:
	1. Do Something (second)
	2. First Menu
	3. Quit
> 2
Title of First Menu:
	1. Do Something (first)
	2. Second Menu
	3. Continue
	4. Quit
> 3
In ds2 after return to menu 
In ds2 after return to menu 
In ds1 after return to menu 
In ds1 after return to menu 
Continue after menu call