https://github.com/jechol/reather

Either transformed Reader monad (reather = REAder + eiTHER)
https://github.com/jechol/reather

Last synced: about 1 year ago
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Either transformed Reader monad (reather = REAder + eiTHER)

• Host: GitHub
• URL: https://github.com/jechol/reather
• Owner: jechol
• License: other
• Created: 2022-01-24T09:16:37.000Z (over 4 years ago)
• Default Branch: main
• Last Pushed: 2024-05-03T08:35:36.000Z (about 2 years ago)
• Last Synced: 2025-04-10T06:09:14.705Z (about 1 year ago)
• Language: Elixir
• Homepage:
• Size: 333 KB
• Stars: 11
• Watchers: 2
• Forks: 0
• Open Issues: 10
• Metadata Files:
  • Readme: README.md
  • License: LICENSE.md

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README

          
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`reather`[ˈriːθə(r)] is `def` for Witchcraft's Reader + Either monads.

## Installation

The package can be installed by adding `reather` to your list of dependencies

in `mix.exs`:

```elixir

def deps do

  [{:reather, "~> 0.1"}]

end

```

To format `reather` like `def`, add following to your `.formatter.exs`

```elixir

locals_without_parens: [reather: 2]

```

## Usage

#### `reather`, `ask`, `let`, `run`

```elixir

defmodule Example do

  use Reather

  reather next(number) do

    n <- number

    %{step: step} <- Reather.ask()

    let sum = n + step

    sum

  end

  test "next/1" do

    assert Right.new(15) == next(10) |> Reather.run(%{step: 5})

    assert Right.new(15) == next(Right.new(10)) |> Reather.run(%{step: 5})

    assert Right.new(15) == next(Reather.of(10)) |> Reather.run(%{step: 5})

    assert Left.new(:NaN) == next(Left.new(:NaN)) |> Reather.run(%{step: 5})

    assert Left.new(:NaN) == next(Reather.of(Left.new(:NaN))) |> Reather.run(%{step: 5})

  end

end

```

## License

This project is licensed under the MIT License - see the [LICENSE](LICENSE.md) file for details