Copyright | (c) Galois Inc 2013-2014 |
---|---|
Maintainer | Joe Hendrix <jhendrix@galois.com> |
Safe Haskell | None |
Language | Haskell98 |
Data.Parameterized.TH.GADT
Description
This module declares template Haskell primitives so that it is easier to work with GADTs that have many constructors.
- structuralEquality :: TypeQ -> [(TypePat, ExpQ)] -> ExpQ
- structuralTypeEquality :: TypeQ -> [(TypePat, ExpQ)] -> ExpQ
- structuralTypeOrd :: TypeQ -> [(TypePat, ExpQ)] -> ExpQ
- structuralTraversal :: TypeQ -> [(TypePat, ExpQ)] -> ExpQ
- structuralShowsPrec :: TypeQ -> ExpQ
- structuralHash :: TypeQ -> ExpQ
- class PolyEq u v where
- type DataD = DatatypeInfo
- lookupDataType' :: Name -> Q DatatypeInfo
- asTypeCon :: Monad m => String -> Type -> m Name
- conPat :: ConstructorInfo -> String -> Q (Pat, [Name])
- data TypePat
- dataParamTypes :: DatatypeInfo -> [Type]
- assocTypePats :: [Type] -> [(TypePat, v)] -> Type -> Q (Maybe v)
Documentation
structuralEquality :: TypeQ -> [(TypePat, ExpQ)] -> ExpQ Source #
declareStructuralEquality
declares a structural equality predicate.
structuralTypeEquality :: TypeQ -> [(TypePat, ExpQ)] -> ExpQ Source #
structuralTypeEquality f
returns a function with the type:
forall x y . f x -> f y -> Maybe (x :~: y)
structuralTypeEquality f
returns a function with the type:
forall x y . f x -> f y -> OrderingF x y
This implementation avoids matching on both the first and second parameters in a simple case expression in order to avoid stressing GHC's coverage checker. In the case that the first and second parameters have unique constructors, a simple numeric comparison is done to compute the result.
structuralTraversal :: TypeQ -> [(TypePat, ExpQ)] -> ExpQ Source #
structuralTraversal tp
generates a function that applies
a traversal f
to the subterms with free variables in tp
.
structuralShowsPrec :: TypeQ -> ExpQ Source #
structuralShow tp
generates a function with the type
tp -> ShowS
that shows the constructor.
structuralHash :: TypeQ -> ExpQ Source #
structuralHash tp
generates a function with the type
Int -> tp -> Int
that hashes type.
class PolyEq u v where Source #
A polymorphic equality operator that generalizes TestEquality
.
Minimal complete definition
Instances
PolyEq (NatRepr m) (NatRepr n) Source # | |
TestEquality k f => PolyEq (Assignment k f x) (Assignment k f y) Source # | |
Template haskell utilities that may be useful in other contexts.
type DataD = DatatypeInfo Source #
lookupDataType' :: Name -> Q DatatypeInfo Source #
Arguments
:: ConstructorInfo | constructor information |
-> String | generated name prefix |
-> Q (Pat, [Name]) | pattern and bound names |
Given a constructor and string, this generates a pattern for matching the expression, and the names of variables bound by pattern in order they appear in constructor.
dataParamTypes :: DatatypeInfo -> [Type] Source #