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": "33959d05-54f5-4b4b-b17d-b3cd0ed0090a",
    "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": {
        "f991b0f6-43fb-4bfb-a43f-3455d77e2047": {
            "id": "f991b0f6-43fb-4bfb-a43f-3455d77e2047",
            "weight": 1,
            "async": false,
            "active": true,
            "schema": "http:\/\/pvm.forma-pro.com\/schemas\/Transition.json",
            "from": "calculate_total_price",
            "to": "calculate_shipping_price"
        },
        "b61631bd-3489-431a-9437-8994f26445ce": {
            "id": "b61631bd-3489-431a-9437-8994f26445ce",
            "weight": 1,
            "async": false,
            "active": true,
            "schema": "http:\/\/pvm.forma-pro.com\/schemas\/Transition.json",
            "to": "calculate_total_price"
        }
    },
    "outTransitions": {
        "calculate_total_price": [
            "f991b0f6-43fb-4bfb-a43f-3455d77e2047"
        ]
    },
    "inTransitions": {
        "calculate_shipping_price": [
            "f991b0f6-43fb-4bfb-a43f-3455d77e2047"
        ],
        "calculate_total_price": [
            "b61631bd-3489-431a-9437-8994f26445ce"
        ]
    },
    "tokens": {
        "a8cc0436-07d1-499e-b2db-aef54738015d": {
            "schema": "http:\/\/pvm.forma-pro.com\/schemas\/Token.json",
            "id": "a8cc0436-07d1-499e-b2db-aef54738015d",
            "transitions": [
                {
                    "schema": "http:\/\/pvm.forma-pro.com\/schemas\/TokenTransition.json",
                    "id": "c991408a-b248-40e1-9c8f-6b5a596083a8",
                    "transitionId": "b61631bd-3489-431a-9437-8994f26445ce",
                    "weight": 1,
                    "state": "opened",
                    "time": 16107334746285
                },
                {
                    "schema": "http:\/\/pvm.forma-pro.com\/schemas\/TokenTransition.json",
                    "id": "a9ae5b26-c12c-409f-864c-064fa28ff770",
                    "transitionId": "b61631bd-3489-431a-9437-8994f26445ce",
                    "weight": 1,
                    "state": "passed",
                    "time": 16107334746289
                },
                {
                    "schema": "http:\/\/pvm.forma-pro.com\/schemas\/TokenTransition.json",
                    "id": "00581c2f-62b2-45f7-93ed-545ec8fde005",
                    "transitionId": "f991b0f6-43fb-4bfb-a43f-3455d77e2047",
                    "weight": 1,
                    "state": "opened",
                    "time": 16107334746291
                },
                {
                    "schema": "http:\/\/pvm.forma-pro.com\/schemas\/TokenTransition.json",
                    "id": "5d7311d5-7011-49bf-8d1e-9a6a5daacb53",
                    "transitionId": "f991b0f6-43fb-4bfb-a43f-3455d77e2047",
                    "weight": 1,
                    "state": "passed",
                    "time": 16107334746296
                }
            ],
            "items": [
                {
                    "price": 85
                },
                {
                    "price": 30
                }
            ],
            "total_price": 115,
            "shipping_price": 11.5
        }
    }
}