Pear FSM composer example

.gitignore

/vendor

README.md

Finite State Machine (FSM)

PHP Finite state machine example.

Research

• https://github.com/pear/FSM
• https://github.com/willdurand/StateMachineBehavior
• https://github.com/yohang/Finite
• http://stackoverflow.com/questions/4274031/php-state-machine-framework

Demo output

Ubuntu (12.04)

sudo apt-get install libgv-php5 graphviz

composer.json

{
    "repositories": [
        {
            "type": "pear",
            "url": "http://pear.php.net"
        }
    ],
    "require": {
        "pear-pear/FSM": "*",
        "pear-pear/Image_GraphViz": "*",
        "pear-pear/PEAR": "*"
    }
}

rpn.php

<?php

// https://github.com/pear/FSM/blob/master/examples/rpn.php
require_once __DIR__ . '/vendor/autoload.php';

function BeginBuildNumber($symbol, $payload)
{
    array_push($payload, $symbol);
}

function BuildNumber($symbol, $payload)
{
    $n = array_pop($payload);
    $n = $n . $symbol;
    array_push($payload, $n);
}

function EndBuildNumber($symbol, $payload)
{
    $n = array_pop($payload);
    array_push($payload, (int)$n);
}

function DoOperator($symbol, $payload)
{
    $ar = array_pop($payload);
    $al = array_pop($payload);

    if ($symbol == '+') {
        array_push($payload, $al + $ar);
    } elseif ($symbol == '-') {
        array_push($payload, $al - $ar);
    } elseif ($symbol == '*') {
        array_push($payload, $al * $ar);
    } elseif ($symbol == '/') {
        array_push($payload, $al / $ar);
    }
}

function DoEqual($symbol, $payload)
{
    echo array_pop($payload) . "\n";
}

function Error($symbol, $payload)
{
    echo "This does not compute: $symbol\n";
}

$stack = array();

$fsm = new FSM('INIT', $stack);
$fsm->setDefaultTransition('INIT', 'Error');

$fsm->addTransitionAny('INIT', 'INIT');
$fsm->addTransition('=', 'INIT', 'INIT', 'DoEqual');
$fsm->addTransitions(range(0,9), 'INIT', 'BUILDING_NUMBER', 'BeginBuildNumber');
$fsm->addTransitions(range(0,9), 'BUILDING_NUMBER', 'BUILDING_NUMBER', 'BuildNumber');
$fsm->addTransition(' ', 'BUILDING_NUMBER', 'INIT', 'EndBuildNumber');
$fsm->addTransitions(array('+','-','*','/'), 'INIT', 'INIT', 'DoOperator');

rpn.sh

#!/bin/sh

echo "2 3 + =" | php rpn_cli.php

# Output:
# Expression:
# 5

rpn_cli.php

<?php

include __DIR__ . '/rpn.php';

echo "Expression:\n";
$stdin = fopen('php://stdin', 'r');
$expression = rtrim(fgets($stdin));
$symbols = preg_split('//', $expression, -1, PREG_SPLIT_NO_EMPTY);
 
$fsm->processList($symbols);

rpn_graph.php

<?php

include __DIR__ . '/rpn.php';

$converter = new FSM_GraphViz($fsm);
$graph = $converter->export();

// $graph->image('png'); // svg, plain, etc...
// $graph->saveParsedGraph('output.dot');
echo "https://chart.googleapis.com/chart?cht=gv&chl=" . urlencode($graph->parse());