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": "26bf68cc-2d88-47e2-b552-e5a86b997edc",
    "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": {
        "761fd7a7-9f1b-42be-ae9b-da8da2ba040a": {
            "id": "761fd7a7-9f1b-42be-ae9b-da8da2ba040a",
            "weight": 1,
            "async": false,
            "active": true,
            "schema": "http:\/\/pvm.forma-pro.com\/schemas\/Transition.json",
            "from": "calculate_total_price",
            "to": "calculate_shipping_price"
        },
        "828ab493-6570-4127-8312-c566223670d4": {
            "id": "828ab493-6570-4127-8312-c566223670d4",
            "weight": 1,
            "async": false,
            "active": true,
            "schema": "http:\/\/pvm.forma-pro.com\/schemas\/Transition.json",
            "to": "calculate_total_price"
        }
    },
    "outTransitions": {
        "calculate_total_price": [
            "761fd7a7-9f1b-42be-ae9b-da8da2ba040a"
        ]
    },
    "inTransitions": {
        "calculate_shipping_price": [
            "761fd7a7-9f1b-42be-ae9b-da8da2ba040a"
        ],
        "calculate_total_price": [
            "828ab493-6570-4127-8312-c566223670d4"
        ]
    },
    "tokens": {
        "f8fb41e1-1983-45c7-8ffe-01ed666dd30e": {
            "schema": "http:\/\/pvm.forma-pro.com\/schemas\/Token.json",
            "id": "f8fb41e1-1983-45c7-8ffe-01ed666dd30e",
            "transitions": [
                {
                    "schema": "http:\/\/pvm.forma-pro.com\/schemas\/TokenTransition.json",
                    "id": "267349fa-1dff-4042-9ac4-9fc937d8cfca",
                    "transitionId": "828ab493-6570-4127-8312-c566223670d4",
                    "weight": 1,
                    "state": "opened",
                    "time": 15508389001027
                },
                {
                    "schema": "http:\/\/pvm.forma-pro.com\/schemas\/TokenTransition.json",
                    "id": "f0c0cfb2-1052-462e-bc94-762678edcb0b",
                    "transitionId": "828ab493-6570-4127-8312-c566223670d4",
                    "weight": 1,
                    "state": "passed",
                    "time": 15508389001035
                },
                {
                    "schema": "http:\/\/pvm.forma-pro.com\/schemas\/TokenTransition.json",
                    "id": "19b86643-6495-4d6d-92b6-f8929e77a967",
                    "transitionId": "761fd7a7-9f1b-42be-ae9b-da8da2ba040a",
                    "weight": 1,
                    "state": "opened",
                    "time": 15508389001041
                },
                {
                    "schema": "http:\/\/pvm.forma-pro.com\/schemas\/TokenTransition.json",
                    "id": "2795afdd-ad53-4b49-9c9b-074dbcc52900",
                    "transitionId": "761fd7a7-9f1b-42be-ae9b-da8da2ba040a",
                    "weight": 1,
                    "state": "passed",
                    "time": 15508389001048
                }
            ],
            "items": [
                {
                    "price": 91
                },
                {
                    "price": 10
                }
            ],
            "total_price": 101,
            "shipping_price": 10.100000000000001
        }
    }
}