types.md

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⬅ 2 🛠 Features

⬅ 2.3 📦 Modules

2.3.3 Type

A type describes the properties a value of that type should have. Each such property is a definition. A definition is then either a method or a immutable variable. Only classes can implement types.

Say I have a server, I could define the type as follows:

type Server
    def connect:            (mut Self, IPAddress) -> Boolean ! ServerErr
    def last_sent_message:  (Self) -> String
    def send_message:       (mut Self, String) -> Boolean    ! ServerErr
    def disconnect:         (mut Self) -> Boolean

This is akin to an abstract base class in Python, but more compact. Now any class that implements Server must have these definitions.

class MyServer(def ip_address: IPAddress): Server
    def connected        <- False
    def mut last_message <- None

    def last_sent_message(self): String := self.last_message

    def connect (mut self, ip_address: IPAddress) -> Boolean ! ServerErr :=
        # perform some operations here
        self.connected := true
        True

    def send_message(mut self, message: String) -> Boolean ! ServerErr :=
        # perform some operations here
        self.last_message := message
        True

    def disconnect(mut self) -> Boolean :=
        # perform some operations here
        self.connected := false
        True