ligo/gitlab-pages/docs/language-basics/functions.md

id	title
functions	Functions

Writing code is fun as long as it doesn't get out of hand. To make sure our code doesn't turn into spaghetti we can group some logic into functions.

Instruction blocks

With block(s) you can wrap instructions and expressions into an isolated scope. Each block needs to include at least one instruction, or a placeholder instruction called skip.

// shorthand syntax
block { skip }
// verbose syntax
begin
    skip
end

Defining a function

Functions in PascaLIGO are defined using the function keyword followed by their name, parameters and return type definitions.

Here's how you define a basic function that accepts two ints and returns a single int:

function add(const a: int; const b: int): int is 
    begin
        const result: int = a + b;
    end with result;

The function body consists of two parts:

• block {<code>} - logic of the function
• with <value> - the return value of the function

Blockless functions

Functions that can contain all of their logic into a single instruction/expression, can be defined without the surrounding block. Instead, you can inline the necessary logic directly, like this:

function add(const a: int; const b: int): int is a + b

Functions in CameLIGO are defined using the let keyword, like value bindings. The difference is that after the value name a list of function parameters is provided, along with a return type.

Here's how you define a basic function that accepts two ints and returns an int as well:

let add (a: int) (b: int) : int = a + b

The function body is a series of expressions, which are evaluated to give the return value.

Functions in ReasonLIGO are defined using the let keyword, like value bindings. The difference is that after the value name a list of function parameters is provided, along with a return type.

Here's how you define a basic function that accepts two ints and returns an int as well:

let add = (a: int, b: int) : int => a + b;

The function body is a series of expressions, which are evaluated to give the return value.

const increment : (int -> int) = (function (const i : int) : int is i + 1);
// a = 2
const a: int = increment(1);

Anonymous functions

Functions without a name, also known as anonymous functions are useful in cases when you want to pass the function as an argument or assign it to a key in a record/map.

Here's how to define an anonymous function assigned to a variable increment, with it's appropriate function type signature.

const increment : (int -> int) = (function (const i : int) : int is i + 1);
// a = 2
const a: int = increment(1);

let increment : (int -> int) = fun (i: int) -> i + 1

let increment: (int => int) = (i: int) => i + 1;