Hi. I have a simple text-base menu system (from the web). I am surprised that all the subroutines involved keep adding the calls to the stack with continual usage. The code is (along with a console output for an execution) ; 

#     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

[download]

With the console output (above), by using the 3 option I continue the program but calling a dummy subroutine (instead of an exit type routine). With this type of usage, you can then appreciate the sequence calls made in accordance to how I have used the menu selections. My concern here is, am I using up the resources of the machine when all I want is a single stack frame stored for just the last subroutine call ?? and a knowledge of where the program counter should continue from when an option 3 (continue) type of operation is performed.

Regards JC....

In reply to Menu system uses the "calling stack" by jmClifford

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.