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Finite state machine: Difference between revisions
→{{header|Phix}}
(Added Wren) |
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</pre>
=={{header|Perl}}==
Added a dummy input called "IMPLICIT" that does not actually require input but automatically transitions to next state.
<lang perl>#!/usr/bin/perl
use strict; # https://rosettacode.org/wiki/Finite_state_machine
use warnings;
my ($state, $action, %fsm) = 'ready';
while( <DATA> )
{
my ($start, $action, $end, $message) = split ' ', $_, 4;
$fsm{$start}{$action} = { next => $end, message => $message || "\n" };
}
while( $state ne 'exit' )
{
print "in state $state\n";
do
{
($action) = grep $_ eq 'IMPLICIT', my @actions = sort keys %{$fsm{$state}};
if( not $action )
{
print "Enter ", join(' or ', @actions), " : ";
chomp($action = uc <STDIN>);
}
}
until $fsm{$state}{$action};
print $fsm{$state}{$action}{message};
$state = $fsm{$state}{$action}{next};
}
# state input newstate displaytext
__DATA__
ready DEPOSIT waiting deposit coins
ready QUIT exit
waiting SELECT dispense remove item
waiting REFUND refunding take the refund
dispense REMOVE ready Thank You
refunding IMPLICIT ready</lang>
{{out}}
<pre>
in state ready
Enter DEPOSIT or QUIT : deposit
deposit coins
in state waiting
Enter REFUND or SELECT : select
remove item
in state dispense
Enter REMOVE : remove
Thank You
in state ready
Enter DEPOSIT or QUIT : deposit
deposit coins
in state waiting
Enter REFUND or SELECT : refund
take the refund
in state refunding
in state ready
Enter DEPOSIT or QUIT : quit
</pre>
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