constrained-some-0.1.2: README.md

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# constrained-some

This library provides utilities for working with existential types and type-level constraints.
It allows you to enforce multiple constraints on polymorphic types and containers complementing `some`.

## Core

- **Existential types**: `Somes` and `Somes1` provide existential wrappers for types with multiple constraints.
- **Convenient aliases**: Simplified types `Some` and `Some1` for scenarios where just one constraint is needed.
- **More convenient aliases**: Simplified types `SomeF` and `SomesF` for scenarios where the container of a `Somes1` is known.
- **Natural transformations with constraints**
    - `mapSome :: (forall a. AllC csa a => f a -> g a) -> SomesF f csa -> SomesF g csa`
    - `traverseSome :: Functor m => (forall a. AllC csa a => f a -> m (g a)) -> SomesF f csa -> m (SomesF g csa)`
## Usage

```haskell
import Data.Some.Constraint

someShowableOrd :: Somes '[Show, Ord]
someShowableOrd = Some [1, 2, 3 :: Int]

someNumFunctor :: Some1 Functor Num
someNumFunctor = Some1 [1, 2, 3 :: Int]

someListShowable :: SomeF [] Show
someListShowable = Some1 [1, 2, 3 :: Int]
```

## Contact information
Contributions, critics and bug reports are welcome!

Please feel free to contact me through GitHub.