ligo/gitlab-pages/docs/reference/toplevel.md

id	title	description	hide_table_of_contents
toplevel	Toplevel	Available functions at the top level	true

import Syntax from '@theme/Syntax'; import SyntaxTitle from '@theme/SyntaxTitle';

These functions are available without any needed prefix.

function is_nat: int -> option(nat) val is_nat: int -> nat option let is_nat: int => option(nat)

Convert an int to a nat if possible.

function abs: int -> nat val abs: int -> nat let abs: int => nat

Cast an int to nat.

function int: nat -> int val int: nat -> int let int: nat => int

Cast an nat to int.

const unit: unit val unit: unit let (): unit

A helper to create a unit.

function failwith : string -> unit val failwith : string -> unit let failwith : string => unit

Cause the contract to fail with an error message.

⚠ Using this currently requires in general a type annotation on the failwith call.

function assert : bool -> unit val assert : bool -> unit let assert : bool => unit

Check if a certain condition has been met. If not the contract will fail.