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Re: General pattern for interactive text-mode script?

by pc88mxer (Vicar)
on Jul 03, 2008 at 18:50 UTC ( #695438=note: print w/ replies, xml ) Need Help??


in reply to General pattern for interactive text-mode script?

Here's a simple FSM implementation. Each subroutine returns the next 'state' (just a subroutine name) to pass control to. To exit, return undef.

my $state = "start"; while (my $next = $state->()) { $state = $next; } sub start { ...get input... if (/1/) { return "menu_1" } elsif (/2/) { return "menu_2" } ... } sub menu_1 { ... } sub menu_2 { ... }


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Re^2: General pattern for interactive text-mode script?
by wazoox (Prior) on Jul 04, 2008 at 10:38 UTC
    Hu, this breaks strictures, better use code references :
    use strict; use warnings; my $state = \&start; while (my $next = $state->()) { $state = $next; } sub start { ...get input... if (/1/) { return \&menu_1 } elsif (/2/) { return \&menu_2 } ... } sub menu_1 { ... } sub menu_2 { ... }
    By the way instead of chaining multiple if () {} blocks, using a dispatch table is more efficient and looks nicer:
    use strict; use warnings; my $state = \&start; while (my $next = $state->()) { $state = $next; } sub start { my %next_action = ( 1 => \&menu_1, 2 => \&menu_2, 3 => \&menu_3, ); return $next_action{$_} if exists $next_action{$_} }

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