Actor model in Elm

Concepts

Some concepts / vocabulary.

Component

• Like an Elm program with out-messages.
• Can NOT know anything about other components.
• Is self contained and can be run as a standalone app. This makes development/testing easy.
• When a component is started (instantiated) it is called a process.
• Each process is identified by a unique PID (process id).
• Knowing a PID, you can send messages to that process.

There are three types of components:

• UI Component
• Service Component
• Layout Component

See Webbhuset.Component for more info.

Actor

• An actor is a component that has been "wrapped" to be part of a system.
• The actor defines how a component's out-messages should be handled.
• Maps received messages to the component's in-message type.
• An actor implements the connections between components.
• The actor uses the ActorSystem module to perform actions, such as sending messages, spawning processes.

System

• Defines which components are avaiable and bootstraps them.

• The "runtime", routes messages, spawns actors etc.