Functions

Functions are first-class citizens in Freight. This means you can assign a function to a variable, pass functions into other functions, and return functions from other functions. They are also the main way of performing logic in Freight.

A function can be defined using the function keyword:

function example() {
  // your code here
}

As with all other structures in Freight, functions are only available in the scope in which they're defined unless you export it:

export function public() {
  // your public code here
}

Defining a function also defines its type. A function's type is made up of its name, arguments, and return value:

export function handler(request: Request) -> Response {
  new Response {
    // ...
  }
}

You can use this type in other functions if you'd like to pass it in:

function listen(port: Integer, handler: handler) {
  // ... call the handler when a request comes in ...
}

Functions can also be abstract, so you can define a specification for a callback function of some kind:

abstract function Handler(request: Request) -> Response