th-desugar release notes

Version 1.7

• Support for TH's support for TypeApplications, thanks to @RyanGlScott.

• Support for unboxed sums, thanks to @RyanGlScott.

• Support for COMPLETE pragmas.

• getRecordSelectors now requires a list of DCons as an argument. This makes it easier to return correct record selector bindings in the event that a record selector appears in multiple constructors. (See goldfirere/singletons#180 for an example of where the old behavior of getRecordSelectors went wrong.)

• Better type family expansion (expanding an open type family with variables works now).

Version 1.6

• Work with GHC 8, with thanks to @christiaanb for getting this change going. This means that several core datatypes have changed: partcularly, we now have DTypeFamilyHead and fixities are now reified separately from other things.

• DKind is merged with DType.

• Generic instances for everything.

Version 1.5.5

• Fix issue #34. This means that desugaring (twice) is idempotent over expressions, after the second time. That is, if you desugar an expression, sweeten it, desugar again, sweeten again, and then desugar a third time, you get the same result as when you desugared the second time. (The extra round-trip is necessary there to make the output smaller in certain common cases.)

Version 1.5.4.1

• Fix issue #32, concerning reification of classes with default methods.

Version 1.5.4

• Added expandUnsoundly

Version 1.5.3

• More DsMonad instances, thanks to David Fox.

Version 1.5.2

• Sweeten kinds more, too.

Version 1.5.1

• Thanks to David Fox (@ddssff), sweetening now tries to use more of TH's Type constructors.

• Also thanks to David Fox, depend usefully on the th-orphans package.

Version 1.5

• There is now a facility to register a list of Dec that internal reification should use when necessary. This avoids the user needing to break up their definition across different top-level splices. See withLocalDeclarations. This has a side effect of changing the Quasi typeclass constraint on many functions to be the new DsMonad constraint. Happily, there are DsMonad instances for Q and IO, the two normal inhabitants of Quasi.

• "Match flattening" is implemented! The functions scExp and scLetDec remove any nested pattern matches.

• More is now exported from Language.Haskell.TH.Desugar for ease of use.

• expand can now expand closed type families! It still requires that the type to expand contain no type variables.

• Support for standalone-deriving and default signatures in GHC 7.10. This means that there are now two new constructors for DDec.

• Support for static expressions, which are new in GHC 7.10.

Version 1.4.2

• expand functions now consider open type families, as long as the type to be expanded has no free variables.

Version 1.4.1

• Added Language.Haskell.TH.Desugar.Lift, which provides Lift instances for all of the th-desugar types, as well as several Template Haskell types.

• Added applyDExp and applyDType as convenience functions.

Version 1.4.0

• All Decs can now be desugared, to the new DDec type.

• Sweetening Decs that do not exist in GHC 7.6.3- works on a "best effort" basis: closed type families are sweetened to open ones, and role annotations are dropped.

• Infos can now be desugared. Desugaring takes into account GHC bug #8884, which meant that reifying poly-kinded type families in GHC 7.6.3- was subtly wrong.

• There is a new function flattenDValD which takes a binding like let (a,b) = foo and breaks it apart into separate assignments for a and b.

• There is a new Desugar class with methods desugar and sweeten. See the documentation in Language.Haskell.TH.Desugar.

• Variable names that are distinct in desugared code are now guaranteed to have distinct answers to nameBase.

• Added a new function getRecordSelectors that extracts types and definitions of record selectors from a datatype definition.

Version 1.3.1

• Update cabal file to include testing files in sdist.

Version 1.3.0

• Update to work with type Pred = Type in GHC 7.9. This changed the DPred type for all GHC versions, though.

Version 1.2.0

• Generalized interface to allow any member of the Qausi class, instead of just Q.

Version 1.1.1

• Made compatible with HEAD after change in role annotation syntax.

Version 1.1

• Added module Language.Haskell.TH.Desugar.Expand, which allows for expansion of type synonyms in desugared types.
• Added Show, Typeable, and Data instances to desugared types.
• Fixed bug where an as-pattern in a let statement was scoped incorrectly.
• Changed signature of dsPat to be more specific to as-patterns; this allowed for fixing the let scoping bug.
• Created new functions dsPatOverExp and dsPatsOverExp to allow for easy desugaring of patterns.
• Changed signature of dsLetDec to return a list of DLetDecs.
• Added dsLetDecs for convenience. Now, instead of using mapM dsLetDec, you should use dsLetDecs.

Version 1.0

• Initial release