# View Source Quark.Compose (Quark v2.3.3-doma)

Function composition is taking two functions, and joining them together to create a new function. For example:

##
examples

Examples

```
iex> sum_plus_one = compose([&(&1 + 1), &Enum.sum/1])
...> sum_plus_one.([1,2,3])
7
```

In this case, we have joined `Enum.sum`

with a function that adds one,
to create a new function that takes a list, sums it, and adds one.

Note that composition normally applies *from right to left*, though `Quark`

provides the opposite in the form of `*_forward`

functions.

# Link to this section Summary

## Functions

Infix "forward" compositon operator

Function composition, from the tail of the list to the head

Function composition

Compose functions, from the head of the list of functions.

Function composition, from the head to tail (left-to-right)

# Link to this section Functions

Infix "forward" compositon operator

##
examples

Examples

```
iex> sum_plus_one = (&Enum.sum/1) <~> fn x -> x + 1 end
...> sum_plus_one.([1, 2, 3])
7
iex> x200 = (&(&1 * 2)) <~> (&(&1 * 10)) <~> (&(&1 * 10))
...> x200.(5)
1000
iex> add_one = &(&1 + 1)
...> piped = [1, 2, 3] |> Enum.sum() |> add_one.()
...> composed = [1, 2, 3] |> ((&Enum.sum/1) <~> add_one).()
...> piped == composed
true
```

Function composition, from the tail of the list to the head

##
examples

Examples

```
iex> sum_plus_one = compose([&(&1 + 1), &Enum.sum/1])
...> [1,2,3] |> sum_plus_one.()
7
```

Function composition

##
examples

Examples

```
iex> sum_plus_one = compose(&(&1 + 1), &Enum.sum/1)
...> [1, 2, 3] |> sum_plus_one.()
7
```

Compose functions, from the head of the list of functions.

##
examples

Examples

```
iex> sum_plus_one = compose_forward([&Enum.sum/1, &(&1 + 1)])
...> sum_plus_one.([1, 2, 3])
7
```

Function composition, from the head to tail (left-to-right)

##
examples

Examples

```
iex> sum_plus_one = compose_forward(&Enum.sum/1, &(&1 + 1))
...> [1, 2, 3] |> sum_plus_one.()
7
```