> For the complete documentation index, see [llms.txt](https://docs.cheddar.vihan.org/docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.cheddar.vihan.org/docs/functions/operations/functional-composition.md).

# Functional Composition

## Syntax

```swift
f + g
```

## Explanation

Performs functional composition on the two operands. Returns a function which passes its arguments to `g` and then too `f`.

The following are equivilent:

```swift
(f + g)(a,b) == f(g(a,b))
```

## Examples

An example to change a zero-indexed function to a one-indexed function utilizing composition is:

```swift
let fibonacci = n f -> n < 2 ? 1 : f(n - 1) + f(n - 2);
let increment = (+) & 1;

( fibonacci + increment )( 5 ) == 13
```