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

---
id: functions
title: 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`.

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<!--Pascaligo-->

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

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## Defining a function

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<!--Pascaligo-->

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`:


```pascaligo group=a
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:

```pascaligo group=b
function add(const a: int; const b: int): int is a + b
```

<!--CameLIGO-->

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:

```cameligo group=b
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.


<!--ReasonLIGO-->

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:

```reasonligo group=b
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.

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<!--DOCUSAURUS_CODE_TABS-->
<!--Pascaligo-->
```pascaligo group=b
const increment : (int -> int) = (function (const i : int) : int is i + 1);
// a = 2
const a: int = increment(1);
```
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## 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.
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<!--Pascaligo-->
```pascaligo group=c
const increment : (int -> int) = (function (const i : int) : int is i + 1);
// a = 2
const a: int = increment(1);
```

<!--CameLIGO-->
```cameligo group=c
let increment : (int -> int) = fun (i: int) -> i + 1
```

<!--ReasonLIGO-->
```reasonligo group=c
let increment: (int => int) = (i: int) => i + 1;
```

<!--END_DOCUSAURUS_CODE_TABS-->