core/Func

Functions on functions, creating functions from simpler inputs.

(Most commonly used when programming in functional style using higher-order functions.)

Import from the core library to use this module.

import Func = "mo:core/Func";

Function compose

func compose<A, B, C>(f : B -> C, g : A -> B) : A -> C

The composition of two functions f and g is a function that applies g and then f.

Example:

import Text "mo:core/Text";
import Char "mo:core/Char";

let textFromNat32 = Func.compose(Text.fromChar, Char.fromNat32);
assert textFromNat32(65) == "A";

Function identity

func identity<A>(x : A) : A

The identity function returns its argument. Example:

assert Func.identity(10) == 10;
assert Func.identity(true) == true;

Function const

func const<A, B>(x : A) : B -> A

The const function is a curried function that accepts an argument x, and then returns a function that discards its argument and always returns the x.

Example:

assert Func.const<Nat, Text>(10)("hello") == 10;
assert Func.const(true)(20) == true;