https://github.com/raehik/type-level-show

Utilities for writing Show-like type families
https://github.com/raehik/type-level-show

Last synced: about 2 months ago
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Utilities for writing Show-like type families

• Host: GitHub
• URL: https://github.com/raehik/type-level-show
• Owner: raehik
• License: mit
• Created: 2024-05-04T22:58:36.000Z (8 months ago)
• Default Branch: main
• Last Pushed: 2024-06-01T15:14:30.000Z (7 months ago)
• Last Synced: 2024-06-11T18:32:41.035Z (7 months ago)
• Language: Haskell
• Size: 34.2 KB
• Stars: 0
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • Changelog: CHANGELOG.md
  • License: LICENSE

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README

        
# type-level-show

Utilities for writing `Show`-like type families i.e. instead of `showsPrec

:: Int -> a -> ShowS`, we have `ShowsPrec :: Natural -> k -> Symbol`.

Requires at least GHC 9.6 for the builtin `SChar` etc. singletons.

## Why?

[refined-hackage]: https://hackage.haskell.org/package/refined

[rerefined-hackage]: https://hackage.haskell.org/package/rerefined

[refined][refined-hackage] fills out error messages using `TypeRep`s. My rewrite

[rerefined][rerefined-hackage] allows you to use `Typeable` to fill out a

predicate name, or you can do it yourself. But `TypeRep` is a pain to use, and

it seems strange to do runtime work on type representations. Why can't we just

do it on the type level?

We _could_, but the problem is nice formatting. `Show` instances handle

precedence, and the base library provides a bunch of handy utilities such as

`showParen :: Bool -> ShowS -> ShowS`. Worse, I couldn't find a `ShowNat ::

Natural -> Symbol` type family on Hoogle, which is a very simple type family

that should certainly be lying around.

This library intends to provide such utilities, so that rerefined can avoid

`Typeable` altogether.

Unsure if I'll provide a `ShowType`. Lower priority than the plain utilities.

## License

Provided under the MIT license. See `LICENSE` for license text.