https://github.com/linkdd/rustic_maybe

Maybe monad for Elixir inspired by Rust Option type
https://github.com/linkdd/rustic_maybe

elixir functional maybe-monad monad option-type

Last synced: 23 days ago
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Maybe monad for Elixir inspired by Rust Option type

• Host: GitHub
• URL: https://github.com/linkdd/rustic_maybe
• Owner: linkdd
• License: mit
• Created: 2021-11-06T00:09:10.000Z (about 3 years ago)
• Default Branch: main
• Last Pushed: 2021-11-06T00:13:35.000Z (about 3 years ago)
• Last Synced: 2024-11-23T20:41:47.660Z (about 1 month ago)
• Topics: elixir, functional, maybe-monad, monad, option-type
• Language: Elixir
• Homepage:
• Size: 7.81 KB
• Stars: 1
• Watchers: 2
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE.txt

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README

        
# Rustic Maybe

[![CICD](https://github.com/linkdd/rustic_maybe/actions/workflows/test-suite.yml/badge.svg)](https://github.com/linkdd/rustic_maybe)

[![Hex.pm](http://img.shields.io/hexpm/v/rustic_maybe.svg?style=flat)](https://hex.pm/packages/rustic_maybe)

[![License](https://img.shields.io/hexpm/l/rustic_maybe)](https://github.com/linkdd/rustic_maybe/blob/main/LICENSE.txt)

[![Hex Docs](https://img.shields.io/badge/hex-docs-lightgreen.svg)](https://hexdocs.pm/rustic_maybe/)

Maybe monad for Elixir inspired by Rust

[Option](https://doc.rust-lang.org/std/option/) type.

## Installation

This package can be installed by adding `rustic_maybe` to your list of

dependencies in `mix.exs`:

```elixir

def deps do

  [

    {:rustic_maybe, "~> 0.1.0"}

  ]

end

```

## Usage

```elixir

import Rustic.Maybe

some(1) == {:some, 1}

# true

nothing() == :nothing

# true

some(1) |> unwrap!()

# 1

nothing() |> unwrap!()

# ** (ArgumentError) trying to unwrap an empty Maybe monad

some(1) |> map(fn n -> n + 1 end)

# some(2)

nothing() |> map(fn n -> n + 1 end)

# nothing()

some(1) |> and_then(fn n -> some(n + 1) end)

# some(2)

nothing() |> and_then(fn n -> some(n + 1) end)

# nothing()

some(1) |> or_else(fn -> some(2) end)

# some(1)

nothing() |> or_else(fn -> some(2) end)

# some(2)

some(1) |> filter(fn n -> n > 0 end)

# some(1)

some(-1) |> filter(fn n -> n > 0 end)

# nothing()

nothing() |> filter(fn n -> n > 0 end)

# nothing()

```

For more examples, please consult the

[API reference](https://hexdocs.pm/rustic_maybe/Rustic.Maybe.html#content).

With function guards:

```elixir

import Rustic.Maybe

def handle_option(val) when is_nothing(val) do

  # ...

end

def handle_option(val) when is_some(val) do

  # ...

end

def handle_result(val) do

  raise ArgumentError, message: "#{inspect(val)} is not a Maybe monad"

end

```

## Usage with Rustic.Result

[Rustic.Result](https://github.com/rustic_result) is an implementation of the

Result monad, inspired by Rust's Result type.

**Result.Maybe** does not depend on **Rustic.Result** but can still work with

its data type:

```elixir

alias Rustic.Result  # if you installed it

alias Rustic.Maybe

Maybe.some(1) |> Maybe.ok_or(:no_value) == Result.ok(1)

# true

Maybe.nothing() |> Maybe.ok_or(:no_value) == Result.err(:no_value)

# true

Maybe.some(Result.ok(1)) |> Maybe.transpose() == Result.ok(Maybe.some(1))

# true

Maybe.some(Result.err(:no_value)) |> Maybe.transpose() == Result.err(:no_value)

# true

Maybe.nothing() |> Maybe.transpose() == Result.ok(Maybe.nothing())

# true

```

For more examples, please consult the

[API reference](https://hexdocs.pm/rustic_maybe/Rustic.Maybe.html#content).