https://github.com/int-index/union

Extensible type-safe unions for Haskell
https://github.com/int-index/union

Last synced: 3 months ago
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Extensible type-safe unions for Haskell

• Host: GitHub
• URL: https://github.com/int-index/union
• Owner: int-index
• License: bsd-3-clause
• Created: 2016-02-02T22:37:07.000Z (almost 9 years ago)
• Default Branch: master
• Last Pushed: 2024-09-10T10:24:03.000Z (4 months ago)
• Last Synced: 2024-10-11T23:53:05.863Z (3 months ago)
• Language: Haskell
• Size: 25.4 KB
• Stars: 31
• Watchers: 5
• Forks: 2
• Open Issues: 4
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# Union

[![Build Status](https://github.com/int-index/union/workflows/CI/badge.svg)](https://github.com/int-index/union/actions)

[![Hackage](https://img.shields.io/hackage/v/union.svg)](https://hackage.haskell.org/package/union)

Extensible type-safe unions.

```

ghci> let a = openUnion # (5 :: Int) :: OpenUnion '[Bool, Int]

ghci> a ^? openUnion :: Maybe Int

Just 5

ghci> a ^? openUnion :: Maybe Bool

Nothing

ghci> a ^? openUnion :: Maybe Char

:8:6:

    No instance for (UElem Char '[] (RIndex Char '[]))

      arising from a use of ‘openUnion’

    In the second argument of ‘(^?)’, namely ‘openUnion’

    In the expression: a ^? openUnion :: Maybe Char

    In an equation for ‘it’: it = a ^? openUnion :: Maybe Char

```