https://github.com/artemeff/fn

More functional Erlang
https://github.com/artemeff/fn

Last synced: about 2 months ago
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More functional Erlang

• Host: GitHub
• URL: https://github.com/artemeff/fn
• Owner: artemeff
• License: mit
• Created: 2015-04-13T18:26:48.000Z (over 9 years ago)
• Default Branch: master
• Last Pushed: 2016-01-07T06:39:18.000Z (almost 9 years ago)
• Last Synced: 2024-10-29T08:42:40.251Z (2 months ago)
• Language: Erlang
• Homepage:
• Size: 4.88 KB
• Stars: 10
• Watchers: 2
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
### fn [![Build Status](https://img.shields.io/travis/artemeff/fn.svg)](https://travis-ci.org/artemeff/fn) [![Hex.pm](https://img.shields.io/hexpm/v/fn.svg)](fn)

---

###### Function composition `(f ∘ g)(x) = f(g(x))`

```erlang

Fn = fn:compose(fun(X) -> X + X end, fun(X) -> X * 4 end)

Fn(10) % => 80

Fn(12) % => 96

```

---

###### Multiple function composition `(f ∘ g ∘ h)(x) = f(g(h(x)))`

```erlang

Fn = fn:compose(

    [ fun(X) -> X + 3 end

    , fun(X) -> X * 4 end

    , fun(X) -> X - 2 end

    ])

Fn(10) % => 50

Fn(13) % => 62

```

---

###### Naive application `f $ g $ h $ x = f(g(h(x)))`

```erlang

Val = fn:naive(

    [ fun(X) -> X + 3 end

    , fun(X) -> X * 4 end

    , fun(X) -> X - 2 end

    ], 10),

Val % => 50

```

---

###### Error monad application

```erlang

Val1 = fn:error_monad(

    [ fun(X) -> {ok, X + 3} end

    , fun(X) -> {ok, X * 4} end

    , fun(X) -> {ok, X - 2} end

    ], 10),

Val1 % => {ok, 50}

Val2 = fn:error_monad(

    [ fun(X) -> {ok, X + 3} end

    , fun(X) -> {ok, X * 4} end

    , fun(_) -> {error, something_went_wrong} end

    ], 10),

Val2 % => {error, something_went_wrong}

```

---

###### Partial application

```erlang

Fn1 = fn:partial(fun lists:map/2, [fun erlang:list_to_atom/1])

Fn1(["test", "partial"]) % => [test, partial]

Fn2 = fn:partial(fun lists:foldl/3, [fun(X, Acc) -> X * Acc end, 1])

Fn2([2, 5, 10]) % => 100

```

---

### Contributing

1. Fork it

2. Create your feature branch (`git checkout -b my-new-feature`)

3. Commit your changes (`git commit -am 'add some feature'`)

4. Push to the branch (`git push origin my-new-feature`)

5. Create new Pull Request