https://github.com/nwtgck/open-union-sugar-haskell

Syntactic sugar for open-union
https://github.com/nwtgck/open-union-sugar-haskell

haskell haskell-library open-union quasiquoter template-haskell

Last synced: 9 days ago
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Syntactic sugar for open-union

• Host: GitHub
• URL: https://github.com/nwtgck/open-union-sugar-haskell
• Owner: nwtgck
• License: bsd-3-clause
• Created: 2018-02-18T08:10:49.000Z (almost 7 years ago)
• Default Branch: develop
• Last Pushed: 2018-04-21T02:37:46.000Z (over 6 years ago)
• Last Synced: 2024-10-26T17:24:08.388Z (about 2 months ago)
• Topics: haskell, haskell-library, open-union, quasiquoter, template-haskell
• Language: Haskell
• Homepage:
• Size: 21.5 KB
• Stars: 0
• Watchers: 3
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • Changelog: CHANGELOG.md
  • License: LICENSE

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README

        
# open-union-sugar

| branch | status|

| --- | --- |

| [`master`](https://github.com/nwtgck/open-union-sugar-haskell/tree/master) | [![Build Status](https://travis-ci.org/nwtgck/open-union-sugar-haskell.svg?branch=master)](https://travis-ci.org/nwtgck/open-union-sugar-haskell) |

| [`develop`](https://github.com/nwtgck/open-union-sugar-haskell/tree/develop) | [![Build Status](https://travis-ci.org/nwtgck/open-union-sugar-haskell.svg?branch=develop)](https://travis-ci.org/nwtgck/open-union-sugar-haskell) |

Syntactic sugar for [open-union](https://hackage.haskell.org/package/open-union)

## Install

### For [Stack](https://docs.haskellstack.org/en/stable/README/) users

Add this library to `extra-deps` in your `stack.yaml` like the following.

```yaml

...

extra-deps:

- git: https://github.com/nwtgck/open-union-sugar-haskell.git

  commit: 24ad5c35054dc511308bb5186cf17784042c499a

...

```

Then, add `open-union-sugar` to your `package.yaml` like the following.

```yaml

...

library:

 dependencies:

 - open-union-sugar

...

```

## Usage

### `l` quote

```hs

{-# LANGUAGE DataKinds #-}

{-# LANGUAGE QuasiQuotes #-}

import Data.OpenUnion

import Data.OpenUnion.Sugar

main :: IO ()

main = do

    let u1 :: Union '[Int, String]

        u1 = [l|"hello"|]

    print u1

    -- => Union ("hello" :: [Char])

```

### `hlist` quote

```hs

{-# LANGUAGE DataKinds #-}

{-# LANGUAGE QuasiQuotes #-}

import Data.OpenUnion

import Data.OpenUnion.Sugar

main :: IO ()

main = do

    let hlist1 :: [Union '[Char, Bool, String]]

        hlist1 = [hlist|

                    'a'

                  , True

                  , "apple"

                  , 'z'

                  , False

                  , "orange"

                 |]

    print hlist1

    -- => [Union ('a' :: Char),Union (True :: Bool),Union ("apple" :: [Char]),Union ('z' :: Char),Union (False :: Bool),Union ("orange" :: [Char])]

```

### `ptn` quote

```hs

{-# LANGUAGE DataKinds #-}

{-# LANGUAGE QuasiQuotes #-}

{-# LANGUAGE ScopedTypeVariables #-}

import Data.OpenUnion

import Data.OpenUnion.Sugar

type UnitList = [()]

showMyUnion :: Union '[Char, Int, String, UnitList] -> String

[ptn|

showMyUnion (c :: Char)     = "char: " ++ show c

showMyUnion (i :: Int)      = "int: " ++ show i

showMyUnion (s :: String)   = "string: " ++ s

showMyUnion (l :: UnitList) = "list length: " ++ show (length l)

|]

main :: IO ()

main = do

    let u1 :: Union '[Char, Int, String, UnitList]

        u1 = [l|"hello"|]

    putStrLn (showMyUnion u1)

    -- => string: hello

    let u2 :: Union '[Char, Int, String, UnitList]

        u2 = [l|189 :: Int|]

    putStrLn (showMyUnion u2)

    -- => int: 189

```