Function types

Function types are type signatures which corresponds to a function signature. Only functions which match the parameter types and return types are compatible with the signature.

Function types are useful with higher order functions.

function ( parametertypes ) [ : returntype ]

Example:

var t : (function(int):int);

By the above definition, t can only be assigned a function which matches the provided signature:

function f(a : int) { return a; }
t = f; // OK
   
function g(a : int) { }
t = g; // ERROR - g does not have the same return type