# Changelog for the `parameterized-utils` package

## 2.1.3.0 -- *2021 Mar 23*

  * Add support for GHC 9.
  * In the `Context` module:
    * Added `sizeToNatRepr` function for converting a `Context` `Size`.
    * Added `unzip` to unzip an `Assignment` of `Product(Pair)` into a
      separate `Assignment` for each element of the `Pair` (the
      inverse of the `zipWith Pair` operation).
    * Added `flattenAssignment` to convert an `Assignment` of
      `Assignment` into an `Assignment` of `CtxFlatten`.  Also adds
      `flattenSize` to combine the sizes of each context into the size
      of the corresponding `CtxFlatten`.
  * In the `Vector` module:
    * Added `fromAssignment` and `toAssignment` to allow conversions
      between `Assignment` and `Vector`.
    * Added `unsnoc`, `unfoldr`, `unfoldrM`, `unfoldrWithIndex`, and
      `unfoldrWithIndexM` functions.
  * Various haddock documentation updates and corrections.
  * Updated the Cabal specification to Cabal-version 2.2.


## 2.1.2 -- *2021 Jan 25*

  * Added `SomeSym` and `viewSomeSym` for existentially hidden Symbol
    values which retain the `KnownSymbol` constraint.
  * Added `leftIndex` and `rightIndex` for re-casting indexes of the
    individual parts of an Assignment into the concatenated
    Assignment.
  * Additional tests and updated documentation.

## 2.1.1 -- *2020 Jul 30*

  * Added `drop` and `appendEmbeddingLeft` functions to the `Context` module.
  * Fixes/updates to haddock documentation (fixing Issue #74).
  * Allow tasty v1.3 for testing (thanks to felixonmars)

## 2.1.0 -- *2020 May 08*

  * Added `plusAssoc` to the `NatRepr` module to produce `+` associativity evidence.
  * Changed the `HashTable` module to use the Basic instead of the Cuckoo
    implementation strategy.
  * Added explicit kind parameters to various definitions to support
    GHC 8.10's adoption of [proposal 103](https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0103-no-kind-vars.rst).
    This is a modification to the type signatures which _may impact_
    backward-compatibility and require updates, especially for any
    uses of
    [`TypeApplications`](https://gitlab.haskell.org/ghc/ghc/-/wikis/type-application).
  * No longer verifying support for GHC 8.2 or earlier.
  * Updated the minimum cabal version to 1.10 and specify the
    default-language as Haskell2010.

## 2.0.2 -- *2020 Feb 10*

  * Add the `dropPrefix` operation to `Context` which splits an `Assignment`.
  * Add `intersectWithKeyMaybe` and `mergeWithKey` to `Map`.
  * Add `mapAt`, `mapAtM`, and `replace` to `Vector`.
  * Add dependency on `base-orphans` to handle the `TestEquality`
    instance for `Compose`; needed for GHC 8.10.
  * Bump upper limit of `lens` dependency to allow 4.19.

## 2.0.1 -- *2019 Nov 06*

  * Documentation updates
  * Dependency constraint updates: constraints, lens, th-abstraction, hashable, hashtables, and vector.
  * Now supports building under GHC 8.8.1.
  * Added monadic folds and more traversals:
      * lazy folds: `foldlMF`, `foldrMF`, `foldlMFC`, `foldrMFC`
      * strict folds: `foldlMF'`, `foldrMF'`, `foldlMFC'`, `foldrMFC'`
      * `forF`, `forF_`
      * `forFC`, `forFC_`
      * `lengthF`
  * Added monadic folds, ascending or descending list conversions to `Parameterized.Map`:
      * Added monadic folds: `foldlMWithKey`, `foldrMWithKey`
      * Added ascending or descending list conversions: `toAscList` (equivalent to existing `toList`) and `toDescList`.
      * Added `findWithDefault` to lookup a key or return a default value.
      * Added `traverseMaybeWithKey`.
      * Fixes traverse to do an in-order rather than a pre-order traversal.
  * Added the `Data.Parameterized.All` module for universal quantification/parametricity over a type variable.
  * Additions to `Data.Parameterized.Context`:
      * Added `IndexView` type and `viewIndex` functions.
      * Added `addDiff` function to explicitly describe the (flipped) binary operator for the `Diff` instance of the `Category` class from `Control.Category`.
      * Added `traverseWithIndex_`
  * Added `Data.Parameterized.DataKind` providing the `PairRepr` type with associated `fst` and `snd` functions.
  * Added `TypeAp` to `Data.Parameterized.Classes`
  * Added `runSTNonceGenerator` to `Data.Parameterized.Nonce` for a *global* ST generator.
  * Added a `Hashable` instance for list `Index l x` types.
  * Changes in GADT TH code generator:
      * Added `structuralHashWithSalt` to
      * Fixed off by one bug in output
      * Fixed generation and constructor generation to use constructor type arguments, not type parameters.
  * The `Some` type is now an instance of `FunctorF`, `FoldableF`, and `TraversableF`.
  * Adjusted `structuralShowsPrec` precedence to match GHC derived `Show` instances.
  * The `Data.Parameterized.Nonce.Unsafe` module is now deprecated: clients should switch to `Data.Parameterized.Nonce`.

## 2.0 -- *2019 Apr 03*

  * Drop support for GHC versions prior to GHC 8.2
  * Various Haddock and module updates.
  * Data.Parameterized.Classes
    - Added function: `ordFCompose`
    - Added `OrdF` instance for `Compose`
  * Data.Parameterized.ClassesC
    - Marked as `Safe` haskell via pragma
    - Added `OrdC` instance for `Some`
  * Data.Parameterized.Compose
    - Update `testEqualityComposeBare` to be more kind-polymorphic.
    - Marked as `Safe` haskell via pragma
  * Data.Parameterized.Context
    - Added `diffIsAppend` function to extract the contextual
      difference between two `Context`s (as a `Diff`) as an `IsAppend`
      (new) data value if the left is a sub-context of the right.
  * Data.Parameterized.NatRepr
    - Change runtime representation from `Int` to `Natural`
    - Add function `intValue` to recover an `Int` from a `NatRepr`.
    - Add constructor function `mkNatRepr` to construct a `NatRepr`
      from a `Natural`.
    - Removed awkward backdoor for directly creating `NatRepr` values;
      the single needed internal usage is now handled internally.
  * Data.Parameterized.Peano
    - Newly added module.
    - Defines a type `Peano` and `PeanoRepr` for representing a
      type-level natural at runtime.
    - The runtime representation of `PeanoRepr` is `Word64`
    - Has both safe and unsafe implementations.
  * Data.Parameterized.WithRepr
    - Newly added module.
    - This module declares a class `IsRepr` with a single method
      `withRepr` that can be used to derive a 'KnownRepr' constraint
      from an explicit 'Repr' argument. Clients of this method need
      only create an empty instance. The default implementation
      suffices.

## 1.0.8 -- *2019 Feb 01*

  * Data.Parameterized.Map
    - Fixed `MapF` functions `filter` and `filterWithKey`
    - Added `MapF` function: `mapWithKey`
  * Data.Parameterized.NatRepr
    - Un-deprecate `withKnownNat`
  * Data.Parameterized.Context
    - Updated some haddock documentation (esp. `CtxEmbedding` data structure).
  * Data.Parameterized.Nonce
    - Fixed `newIONonceGenerator` haddock documentation (IO monad, not ST monad).
    - Added `countNoncesGenerated` for profiling Nonce usage.
  * Data.Parameterized.TraversableF
    - Added `FunctorF`, `FoldableF`, and `TraversableF` instances for
      `Compose` from Data.Functor.Compose
  * Data.Parameterized.ClassesC
    - Newly added module.
    - Declares `TestEqualityC` and `OrdC` classes for working with
      types that have kind `(k -> *) -> *` for any `k`.
  * Data.Parameterized.Compose
    - Newly added module.
    - Orphan instance and `testEqualityComposeBare` function for
      working with Data.Functor.Compose.
  * Data.Parameterized.TestEquality
    - Newly added module.
    - Utilities for working with Data.Type.TestEquality.

## 1.0.7 -- *2018 Nov 17*

  * Data.Parameterized.Map
    - Added `MapF` functions:
      - `filter`
      - `filterWithKey`

## 1.0.6 -- *2018 Nov 19*

  * Add support for GHC 8.6.
  * Data.Parameterized.Map
    - Added functions:
       - `foldlWithKey` and `foldlWithKey'` (strict)
       - `foldrWithKey` and `foldrWithKey'` (strict)
       - `mapMaybeWithKey`

## 1.0.5 -- *2018 Sep 04*

  * Data.Parameterized.Context
      - Add function: `take`, `appendEmbedding`, `appendDiff`
      - Diff is type role nominal in both parameters.

## 1.0.4 -- *2018 Aug 29*

  * Data.Parameterized.Context
    - Add `traverseAndCollect`.  Allows traversal of an Assignment in
      order from left to right, collecting the results of a visitor
      function monoidically.
  * Data.Parameterized.DecidableEq
    - Newly added module.  The `DecidableEq` class represents
      decideable equality on a type family as a superclass of
      `TestEquality`, where the latter cannot provide evidence of
      non-equality.
  * Data.Parameterized.NatRepr
    - Add `DecidableEq` instance for NatRepr.
    - Add functions:
      - `decideLeq`
      - `isZeroOrGT1`
      - `lessThanIrreflexive`
      - `lessThanAsymmetric`
      - `natRecStrong`  -- recursor with strong induction
      - `natRecBounded` -- bounded recursor
      - `natFromZero`
  * Data.Parameterized.Vector
    - Add construction functions: `singleton`, `cons`, `snoc`, `generate`, and `generateM`
    - Add functions: `splitWithA` (applicative `splitWith`).

## 1.0.3 -- *2018 Aug 24*

  * Move `lemmaMul` from Vector to NatRepr.
  * Add stricter role annotations:
    - `NatRepr` is nominal.
    - `Vector` is nominal in the first parameter and representational in the second.
  * Data.Parameterized.NatRepr
    - Provide a backdoor for directly creating `NatRepr` values.  Use carefully.
  * Data.Parameterized.Vector
    - Add Show and Eq instances
    - Add functions: `joinWithM`, `reverse`

## 1.0.2 -- *2018 Aug 23*

  * Allow function passed to `traverseF_`, `traverseFC_`, and
    `forMFC_` to return a value instead of null (`()`).
  * Data.Parameterized.Vector
    - Newly added module.  A fixed-size vector of typed elements.
  * Data.Parameterized.Utils.Endian
    - Newly added module.  Used in Vector.

## 1.0.1 -- *2018 Aug 13*

  Baseline for changelog tracking.