sequence.php

<?php
use Formapro\Pvm\DefaultBehaviorRegistry;
use Formapro\Pvm\ProcessEngine;
use Formapro\Pvm\Token;
use Formapro\Pvm\ProcessBuilder;

require_once __DIR__.'/vendor/autoload.php';

$process = (new ProcessBuilder())
    ->createNode('calculate_total_price', 'calculate_total_price')->end()
    ->createNode('calculate_shipping_price', 'calculate_shipping_price')->end()

    ->createTransition('calculate_total_price', 'calculate_shipping_price')->end()
    ->createStartTransition('calculate_total_price')->end()

    ->getProcess()
;

$engine = new ProcessEngine(new DefaultBehaviorRegistry([
    'calculate_total_price' => function(Token $token) {
        $totalPrice = 0;
        foreach ($token->getValue('items') as $item) {
            echo 'item price: '.$item['price'].PHP_EOL;

            $totalPrice += $item['price'];
        }

        $token->setValue('total_price', $totalPrice);

        echo 'total price: '.$totalPrice.PHP_EOL;
    },
    'calculate_shipping_price' => function(Token $token) {
        $totalPrice = $token->getValue('total_price');
        $token->setValue('shipping_price', $totalPrice * 0.1);

        echo 'shipping price: '.$token->getValue('shipping_price').PHP_EOL;
    },
]));

$token = $engine->createTokenFor($process->getStartTransition());
$token->setValue('items.0.price', rand(10, 100));
$token->setValue('items.1.price', rand(10, 100));

$engine->proceed($token);

{
    "schema": "http:\/\/pvm.forma-pro.com\/schemas\/Process.json",
    "id": "e975e320-5d96-44b9-a9f7-8b348f63d316",
    "nodes": {
        "calculate_total_price": {
            "schema": "http:\/\/pvm.forma-pro.com\/schemas\/Node.json",
            "id": "calculate_total_price",
            "behavior": "calculate_total_price"
        },
        "calculate_shipping_price": {
            "schema": "http:\/\/pvm.forma-pro.com\/schemas\/Node.json",
            "id": "calculate_shipping_price",
            "behavior": "calculate_shipping_price"
        }
    },
    "transitions": {
        "48d4f40b-59b8-4d6d-a9bc-6357921245c2": {
            "id": "48d4f40b-59b8-4d6d-a9bc-6357921245c2",
            "weight": 1,
            "async": false,
            "active": true,
            "schema": "http:\/\/pvm.forma-pro.com\/schemas\/Transition.json",
            "from": "calculate_total_price",
            "to": "calculate_shipping_price"
        },
        "ccecf9df-b5c0-45dc-89aa-525fa9264bdb": {
            "id": "ccecf9df-b5c0-45dc-89aa-525fa9264bdb",
            "weight": 1,
            "async": false,
            "active": true,
            "schema": "http:\/\/pvm.forma-pro.com\/schemas\/Transition.json",
            "to": "calculate_total_price"
        }
    },
    "outTransitions": {
        "calculate_total_price": [
            "48d4f40b-59b8-4d6d-a9bc-6357921245c2"
        ]
    },
    "inTransitions": {
        "calculate_shipping_price": [
            "48d4f40b-59b8-4d6d-a9bc-6357921245c2"
        ],
        "calculate_total_price": [
            "ccecf9df-b5c0-45dc-89aa-525fa9264bdb"
        ]
    },
    "tokens": {
        "78fdbb2f-f4ca-4315-a271-105123387c26": {
            "schema": "http:\/\/pvm.forma-pro.com\/schemas\/Token.json",
            "id": "78fdbb2f-f4ca-4315-a271-105123387c26",
            "transitions": [
                {
                    "schema": "http:\/\/pvm.forma-pro.com\/schemas\/TokenTransition.json",
                    "id": "1f5f0b77-ffa0-419a-96ce-42082cead23d",
                    "transitionId": "ccecf9df-b5c0-45dc-89aa-525fa9264bdb",
                    "weight": 1,
                    "state": "opened",
                    "time": 15757103283502
                },
                {
                    "schema": "http:\/\/pvm.forma-pro.com\/schemas\/TokenTransition.json",
                    "id": "9b031a3e-f395-44a2-adcf-109851e754ee",
                    "transitionId": "ccecf9df-b5c0-45dc-89aa-525fa9264bdb",
                    "weight": 1,
                    "state": "passed",
                    "time": 15757103283507
                },
                {
                    "schema": "http:\/\/pvm.forma-pro.com\/schemas\/TokenTransition.json",
                    "id": "3aefb925-79f6-47f0-b03b-13fb16cb9038",
                    "transitionId": "48d4f40b-59b8-4d6d-a9bc-6357921245c2",
                    "weight": 1,
                    "state": "opened",
                    "time": 15757103283510
                },
                {
                    "schema": "http:\/\/pvm.forma-pro.com\/schemas\/TokenTransition.json",
                    "id": "1fd1ab16-917a-4c53-b1da-3c2eb8ea2cff",
                    "transitionId": "48d4f40b-59b8-4d6d-a9bc-6357921245c2",
                    "weight": 1,
                    "state": "passed",
                    "time": 15757103283514
                }
            ],
            "items": [
                {
                    "price": 75
                },
                {
                    "price": 74
                }
            ],
            "total_price": 149,
            "shipping_price": 14.9
        }
    }
}