Witha

v0.1.1

Witha

With aspect: Monad chain, like Haskell’s do or Clojure’s cats.core/alet.

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Installation

Add witha to your list of dependencies in mix.exs:

def deps do
  [
    {:witha, "~> 0.1.1"}
  ]
end

Usage

Witha’s syntax is very similer to Elixir’s with.

import Witha

witha Witha.Error, x1 <- {:ok, 1}, do: x1 + 1
# {:ok, 2}

witha Witha.Error,
      [x1 <- {:ok, 1},
       x2 <- {:ok, x1 + 1}],
  do: x1 + x2
# {:ok, 3}

Witha takes pre-defined aspects Witha.Nilable & Witha.Error.

Witha.Nilable (Maybe) can chain term | nil.

witha Witha.Nilable,
      [x1 <- 1,
       x2 <- x1 + 1],
  do: x1 + x2
# 3

witha Witha.Nilable,
      [x1 <- nil,
       x2 <- x1 + 1],
  do: x1 + x2
# nil

Witha.Error (Either) can chain {:ok, term} | {:error, term}.

witha Witha.Error,
      [x1 <- {:ok, 1},
       x2 <- {:ok, x1 + 1}],
  do: x1 + x2
# {:ok, 3}

witha Witha.Error,
      [x1 <- {:error, "駄目"},
       x2 <- {:ok, x1 + 1}],
  do: x1 + x2
# {:error, "駄目"}

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