cassiemeharry/elixir-monad

---

cassiemeharry/elixir-monad.json

{
  "createdAt": "2012-11-16T03:34:41Z",
  "defaultBranch": "master",
  "description": "A monadic system for the Elixir language",
  "fullName": "cassiemeharry/elixir-monad",
  "homepage": null,
  "language": "Elixir",
  "name": "elixir-monad",
  "pushedAt": "2013-09-08T18:02:51Z",
  "stargazersCount": 45,
  "topics": [],
  "updatedAt": "2023-01-28T19:36:38Z",
  "url": "https://github.com/cassiemeharry/elixir-monad"
}

Elixir Monads

This provides a monadic system for [Elixir][elixir], a Ruby-flavored language for the [Erlang VM][erlang].

[elixir] !: http://elixir-lang.org/ [erlang] !: http://www.erlang.org/

When dealing with Erlang libraries, several common patterns emerge:

case Library.might_fail() do
    {:ok, value} ->
        case Library.also_might_fail(value) do
            {:ok, something} ->
                some_pid <- {:ok, something}
            {:error, reason} ->
                some_pid <- {:error, reason}
        end
    {:error, reason} ->
        some_pid <- {:error, reason}
end

By stealing the marvelous idea of Monads from the more mainstream functional languages, you can abstract out that tree like this:

import Monad
import ErrorM

some_pid <- (monad ErrorM do
    value <- Library.might_fail()
    Library.also_might_fail(value)
end)

Wasn’t that easy?