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": "dada6d22-e2ce-4360-9fc9-f7ea4c781b5b",
    "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": {
        "9437e2d5-61dd-42ec-bf93-4852cf427167": {
            "id": "9437e2d5-61dd-42ec-bf93-4852cf427167",
            "weight": 1,
            "async": false,
            "active": true,
            "schema": "http:\/\/pvm.forma-pro.com\/schemas\/Transition.json",
            "from": "calculate_total_price",
            "to": "calculate_shipping_price"
        },
        "5be56d8f-2de3-4ea7-ad04-1f69bb5fbd23": {
            "id": "5be56d8f-2de3-4ea7-ad04-1f69bb5fbd23",
            "weight": 1,
            "async": false,
            "active": true,
            "schema": "http:\/\/pvm.forma-pro.com\/schemas\/Transition.json",
            "to": "calculate_total_price"
        }
    },
    "outTransitions": {
        "calculate_total_price": [
            "9437e2d5-61dd-42ec-bf93-4852cf427167"
        ]
    },
    "inTransitions": {
        "calculate_shipping_price": [
            "9437e2d5-61dd-42ec-bf93-4852cf427167"
        ],
        "calculate_total_price": [
            "5be56d8f-2de3-4ea7-ad04-1f69bb5fbd23"
        ]
    },
    "tokens": {
        "8ea0aa9b-e73d-4435-b63e-15dabe07005e": {
            "schema": "http:\/\/pvm.forma-pro.com\/schemas\/Token.json",
            "id": "8ea0aa9b-e73d-4435-b63e-15dabe07005e",
            "transitions": [
                {
                    "schema": "http:\/\/pvm.forma-pro.com\/schemas\/TokenTransition.json",
                    "id": "8c7c2e07-2aa7-4bea-bd5a-d48a55a8a2cb",
                    "transitionId": "5be56d8f-2de3-4ea7-ad04-1f69bb5fbd23",
                    "weight": 1,
                    "state": "opened",
                    "time": 15606684675250
                },
                {
                    "schema": "http:\/\/pvm.forma-pro.com\/schemas\/TokenTransition.json",
                    "id": "44cdbbf6-a46b-4df6-b893-cc59c9f035b5",
                    "transitionId": "5be56d8f-2de3-4ea7-ad04-1f69bb5fbd23",
                    "weight": 1,
                    "state": "passed",
                    "time": 15606684675254
                },
                {
                    "schema": "http:\/\/pvm.forma-pro.com\/schemas\/TokenTransition.json",
                    "id": "19510857-8a1a-4b26-a385-7175daf5ba01",
                    "transitionId": "9437e2d5-61dd-42ec-bf93-4852cf427167",
                    "weight": 1,
                    "state": "opened",
                    "time": 15606684675257
                },
                {
                    "schema": "http:\/\/pvm.forma-pro.com\/schemas\/TokenTransition.json",
                    "id": "c4fce09a-4de8-4b30-a597-b3194cd41a72",
                    "transitionId": "9437e2d5-61dd-42ec-bf93-4852cf427167",
                    "weight": 1,
                    "state": "passed",
                    "time": 15606684675261
                }
            ],
            "items": [
                {
                    "price": 17
                },
                {
                    "price": 65
                }
            ],
            "total_price": 82,
            "shipping_price": 8.200000000000001
        }
    }
}