README

State Machines in PHP made safe and easy.

Installation

Using Composer:

$ composer require halfowl/statemachine

Example

Imagine an application that holds the state of an article. It has the following states:

• Draft
• Awaiting Copy Edit
• Published

A new article starts in "Draft", gets progressed to "Awaiting Copy Edit", and subsequently "Published". An article in "Awaiting Copy Edit" can go back to being a "Draft".

With this library, you can model the above as:

<?php

use Halfowl\StateMachine\{State, StateMachine, StateTransition};

$draft = new State("DRAFT");
$awaitingCopy = new State("AWAITING_COPY_EDIT");
$published = new State("PUBLISHED");

// StateTransitions define legal state transitions for the StateMachine.
// The second parameter of the constructor takes in an array of States
// that the first State can transition to.
$fromDraft = new StateTransition($draft, [$awaitingCopy]);  // draft->awaiting copy
$fromAwaitingCopy = new StateTransition($awaitingCopy, [$draft, $published]);  // awaiting copy->draft/published

// Put that together into a StateMachine:
$sm = new StateMachine(
    transitions: [
        $fromDraft,
        $fromAwaitingCopy,
    ],
    starting: $draft,
);

$sm->current();                  // => DRAFT
$sm->transition($awaitingCopy);  // => AWAITING_COPY_EDIT
$sm->transition($published);     // => PUBLISHED

API

(Proper auto-generated docs is WIP, tracking in #4)

State

Reference: https://github.com/half0wl/php-StateMachine/blob/main/src/StateInterface.php

• getName(): string

StateMachine

Reference: https://github.com/half0wl/php-StateMachine/blob/main/src/StateMachineInterface.php

• current(): State
• can(): bool
• is(State $s): bool
• transition(State $next): void

StateTransition

Reference: https://github.com/half0wl/php-StateMachine/blob/main/src/StateTransitionInterface.php

• src(): State
• dsts(): State[]
• inDst(): bool

License

MIT