deriving-compat-0.4.2: src/Data/Deriving/Internal.hs
{-# LANGUAGE BangPatterns #-}
{-# LANGUAGE CPP #-}
{-# LANGUAGE GADTs #-}
{-# LANGUAGE MagicHash #-}
#if !(MIN_VERSION_base(4,9,0))
# if __GLASGOW_HASKELL__ >= 800
{-# LANGUAGE TemplateHaskellQuotes #-}
# else
{-# LANGUAGE TemplateHaskell #-}
# endif
#endif
{-|
Module: Data.Deriving.Internal
Copyright: (C) 2015-2017 Ryan Scott
License: BSD-style (see the file LICENSE)
Maintainer: Ryan Scott
Portability: Template Haskell
Template Haskell-related utilities.
-}
module Data.Deriving.Internal where
import Control.Applicative (liftA2)
import Control.Monad (when, unless)
import Data.Foldable (foldr')
#if !(MIN_VERSION_base(4,9,0))
import Data.Functor.Classes (Eq1(..), Ord1(..), Read1(..), Show1(..))
# if !(MIN_VERSION_transformers(0,4,0)) || MIN_VERSION_transformers(0,5,0)
import Data.Functor.Classes (Eq2(..), Ord2(..), Read2(..), Show2(..))
# endif
#endif
import Data.List
import qualified Data.Map as Map
import Data.Map (Map)
import Data.Maybe
import qualified Data.Set as Set
import Data.Set (Set)
import Text.ParserCombinators.ReadPrec (ReadPrec)
import qualified Text.Read.Lex as L
#if MIN_VERSION_base(4,7,0)
import GHC.Read (expectP)
#else
import GHC.Read (lexP)
import Text.Read (pfail)
import Text.Read.Lex (Lexeme)
#endif
#if MIN_VERSION_ghc_prim(0,3,1)
import GHC.Prim (Int#, tagToEnum#)
#endif
#if defined(MIN_VERSION_ghc_boot_th)
import GHC.Lexeme (startsConSym, startsVarSym)
#else
import Data.Char (isSymbol, ord)
#endif
import Language.Haskell.TH.Datatype
import Language.Haskell.TH.Lib
import Language.Haskell.TH.Ppr (pprint)
import Language.Haskell.TH.Syntax
-- Ensure, beyond a shadow of a doubt, that the instances are in-scope
import Data.Functor ()
import Data.Functor.Classes ()
import Data.Foldable ()
import Data.Traversable ()
#ifndef CURRENT_PACKAGE_KEY
import Data.Version (showVersion)
import Paths_deriving_compat (version)
#endif
-------------------------------------------------------------------------------
-- Expanding type synonyms
-------------------------------------------------------------------------------
applySubstitutionKind :: Map Name Kind -> Type -> Type
#if MIN_VERSION_template_haskell(2,8,0)
applySubstitutionKind = applySubstitution
#else
applySubstitutionKind _ t = t
#endif
substNameWithKind :: Name -> Kind -> Type -> Type
substNameWithKind n k = applySubstitutionKind (Map.singleton n k)
substNamesWithKindStar :: [Name] -> Type -> Type
substNamesWithKindStar ns t = foldr' (flip substNameWithKind starK) t ns
-------------------------------------------------------------------------------
-- Via
-------------------------------------------------------------------------------
-- | A type-level modifier intended to be used in conjunction with 'deriveVia'.
-- Refer to the documentation for 'deriveVia' for more details.
data a `Via` b
infix 0 `Via`
-------------------------------------------------------------------------------
-- Type-specialized const functions
-------------------------------------------------------------------------------
fmapConst :: f b -> (a -> b) -> f a -> f b
fmapConst x _ _ = x
{-# INLINE fmapConst #-}
foldrConst :: b -> (a -> b -> b) -> b -> t a -> b
foldrConst x _ _ _ = x
{-# INLINE foldrConst #-}
foldMapConst :: m -> (a -> m) -> t a -> m
foldMapConst x _ _ = x
{-# INLINE foldMapConst #-}
traverseConst :: f (t b) -> (a -> f b) -> t a -> f (t b)
traverseConst x _ _ = x
{-# INLINE traverseConst #-}
eqConst :: Bool
-> a -> a -> Bool
eqConst x _ _ = x
{-# INLINE eqConst #-}
eq1Const :: Bool
-> f a -> f a-> Bool
eq1Const x _ _ = x
{-# INLINE eq1Const #-}
liftEqConst :: Bool
-> (a -> b -> Bool) -> f a -> f b -> Bool
liftEqConst x _ _ _ = x
{-# INLINE liftEqConst #-}
liftEq2Const :: Bool
-> (a -> b -> Bool) -> (c -> d -> Bool)
-> f a c -> f b d -> Bool
liftEq2Const x _ _ _ _ = x
{-# INLINE liftEq2Const #-}
compareConst :: Ordering -> a -> a -> Ordering
compareConst x _ _ = x
{-# INLINE compareConst #-}
ltConst :: Bool -> a -> a -> Bool
ltConst x _ _ = x
{-# INLINE ltConst #-}
compare1Const :: Ordering -> f a -> f a -> Ordering
compare1Const x _ _ = x
{-# INLINE compare1Const #-}
liftCompareConst :: Ordering
-> (a -> b -> Ordering) -> f a -> f b -> Ordering
liftCompareConst x _ _ _ = x
{-# INLINE liftCompareConst #-}
liftCompare2Const :: Ordering
-> (a -> b -> Ordering) -> (c -> d -> Ordering)
-> f a c -> f b d -> Ordering
liftCompare2Const x _ _ _ _ = x
{-# INLINE liftCompare2Const #-}
readsPrecConst :: ReadS a -> Int -> ReadS a
readsPrecConst x _ = x
{-# INLINE readsPrecConst #-}
-- This isn't really necessary, but it makes for an easier implementation
readPrecConst :: ReadPrec a -> ReadPrec a
readPrecConst x = x
{-# INLINE readPrecConst #-}
readsPrec1Const :: ReadS (f a) -> Int -> ReadS (f a)
readsPrec1Const x _ = x
{-# INLINE readsPrec1Const #-}
liftReadsPrecConst :: ReadS (f a)
-> (Int -> ReadS a) -> ReadS [a]
-> Int -> ReadS (f a)
liftReadsPrecConst x _ _ _ = x
{-# INLINE liftReadsPrecConst #-}
liftReadPrecConst :: ReadPrec (f a)
-> ReadPrec a -> ReadPrec [a]
-> ReadPrec (f a)
liftReadPrecConst x _ _ = x
{-# INLINE liftReadPrecConst #-}
liftReadsPrec2Const :: ReadS (f a b)
-> (Int -> ReadS a) -> ReadS [a]
-> (Int -> ReadS b) -> ReadS [b]
-> Int -> ReadS (f a b)
liftReadsPrec2Const x _ _ _ _ _ = x
{-# INLINE liftReadsPrec2Const #-}
liftReadPrec2Const :: ReadPrec (f a b)
-> ReadPrec a -> ReadPrec [a]
-> ReadPrec b -> ReadPrec [b]
-> ReadPrec (f a b)
liftReadPrec2Const x _ _ _ _ = x
{-# INLINE liftReadPrec2Const #-}
showsPrecConst :: ShowS
-> Int -> a -> ShowS
showsPrecConst x _ _ = x
{-# INLINE showsPrecConst #-}
showsPrec1Const :: ShowS
-> Int -> f a -> ShowS
showsPrec1Const x _ _ = x
{-# INLINE showsPrec1Const #-}
liftShowsPrecConst :: ShowS
-> (Int -> a -> ShowS) -> ([a] -> ShowS)
-> Int -> f a -> ShowS
liftShowsPrecConst x _ _ _ _ = x
{-# INLINE liftShowsPrecConst #-}
liftShowsPrec2Const :: ShowS
-> (Int -> a -> ShowS) -> ([a] -> ShowS)
-> (Int -> b -> ShowS) -> ([b] -> ShowS)
-> Int -> f a b -> ShowS
liftShowsPrec2Const x _ _ _ _ _ _ = x
{-# INLINE liftShowsPrec2Const #-}
-------------------------------------------------------------------------------
-- StarKindStatus
-------------------------------------------------------------------------------
-- | Whether a type is not of kind *, is of kind *, or is a kind variable.
data StarKindStatus = NotKindStar
| KindStar
| IsKindVar Name
deriving Eq
-- | Does a Type have kind * or k (for some kind variable k)?
canRealizeKindStar :: Type -> StarKindStatus
canRealizeKindStar t
| hasKindStar t = KindStar
| otherwise = case t of
#if MIN_VERSION_template_haskell(2,8,0)
SigT _ (VarT k) -> IsKindVar k
#endif
_ -> NotKindStar
-- | Returns 'Just' the kind variable 'Name' of a 'StarKindStatus' if it exists.
-- Otherwise, returns 'Nothing'.
starKindStatusToName :: StarKindStatus -> Maybe Name
starKindStatusToName (IsKindVar n) = Just n
starKindStatusToName _ = Nothing
-- | Concat together all of the StarKindStatuses that are IsKindVar and extract
-- the kind variables' Names out.
catKindVarNames :: [StarKindStatus] -> [Name]
catKindVarNames = mapMaybe starKindStatusToName
-------------------------------------------------------------------------------
-- ClassRep
-------------------------------------------------------------------------------
class ClassRep a where
arity :: a -> Int
allowExQuant :: a -> Bool
fullClassName :: a -> Name
classConstraint :: a -> Int -> Maybe Name
-------------------------------------------------------------------------------
-- Template Haskell reifying and AST manipulation
-------------------------------------------------------------------------------
-- For the given Types, generate an instance context and head. Coming up with
-- the instance type isn't as simple as dropping the last types, as you need to
-- be wary of kinds being instantiated with *.
-- See Note [Type inference in derived instances]
buildTypeInstance :: ClassRep a
=> a
-- ^ The typeclass for which an instance should be derived
-> Name
-- ^ The type constructor or data family name
-> Cxt
-- ^ The datatype context
-> [Type]
-- ^ The types to instantiate the instance with
-> DatatypeVariant
-- ^ Are we dealing with a data family instance or not
-> Q (Cxt, Type)
buildTypeInstance cRep tyConName dataCxt varTysOrig variant = do
-- Make sure to expand through type/kind synonyms! Otherwise, the
-- eta-reduction check might get tripped up over type variables in a
-- synonym that are actually dropped.
-- (See GHC Trac #11416 for a scenario where this actually happened.)
varTysExp <- mapM resolveTypeSynonyms varTysOrig
let remainingLength :: Int
remainingLength = length varTysOrig - arity cRep
droppedTysExp :: [Type]
droppedTysExp = drop remainingLength varTysExp
droppedStarKindStati :: [StarKindStatus]
droppedStarKindStati = map canRealizeKindStar droppedTysExp
-- Check there are enough types to drop and that all of them are either of
-- kind * or kind k (for some kind variable k). If not, throw an error.
when (remainingLength < 0 || any (== NotKindStar) droppedStarKindStati) $
derivingKindError cRep tyConName
let droppedKindVarNames :: [Name]
droppedKindVarNames = catKindVarNames droppedStarKindStati
-- Substitute kind * for any dropped kind variables
varTysExpSubst :: [Type]
varTysExpSubst = map (substNamesWithKindStar droppedKindVarNames) varTysExp
remainingTysExpSubst, droppedTysExpSubst :: [Type]
(remainingTysExpSubst, droppedTysExpSubst) =
splitAt remainingLength varTysExpSubst
-- All of the type variables mentioned in the dropped types
-- (post-synonym expansion)
droppedTyVarNames :: [Name]
droppedTyVarNames = freeVariables droppedTysExpSubst
-- If any of the dropped types were polykinded, ensure that they are of kind *
-- after substituting * for the dropped kind variables. If not, throw an error.
unless (all hasKindStar droppedTysExpSubst) $
derivingKindError cRep tyConName
let preds :: [Maybe Pred]
kvNames :: [[Name]]
kvNames' :: [Name]
-- Derive instance constraints (and any kind variables which are specialized
-- to * in those constraints)
(preds, kvNames) = unzip $ map (deriveConstraint cRep) remainingTysExpSubst
kvNames' = concat kvNames
-- Substitute the kind variables specialized in the constraints with *
remainingTysExpSubst' :: [Type]
remainingTysExpSubst' =
map (substNamesWithKindStar kvNames') remainingTysExpSubst
-- We now substitute all of the specialized-to-* kind variable names with
-- *, but in the original types, not the synonym-expanded types. The reason
-- we do this is a superficial one: we want the derived instance to resemble
-- the datatype written in source code as closely as possible. For example,
-- for the following data family instance:
--
-- data family Fam a
-- newtype instance Fam String = Fam String
--
-- We'd want to generate the instance:
--
-- instance C (Fam String)
--
-- Not:
--
-- instance C (Fam [Char])
remainingTysOrigSubst :: [Type]
remainingTysOrigSubst =
map (substNamesWithKindStar (union droppedKindVarNames kvNames'))
$ take remainingLength varTysOrig
isDataFamily :: Bool
isDataFamily = case variant of
Datatype -> False
Newtype -> False
DataInstance -> True
NewtypeInstance -> True
remainingTysOrigSubst' :: [Type]
-- See Note [Kind signatures in derived instances] for an explanation
-- of the isDataFamily check.
remainingTysOrigSubst' =
if isDataFamily
then remainingTysOrigSubst
else map unSigT remainingTysOrigSubst
instanceCxt :: Cxt
instanceCxt = catMaybes preds
instanceType :: Type
instanceType = AppT (ConT (fullClassName cRep))
$ applyTyCon tyConName remainingTysOrigSubst'
-- If the datatype context mentions any of the dropped type variables,
-- we can't derive an instance, so throw an error.
when (any (`predMentionsName` droppedTyVarNames) dataCxt) $
datatypeContextError tyConName instanceType
-- Also ensure the dropped types can be safely eta-reduced. Otherwise,
-- throw an error.
unless (canEtaReduce remainingTysExpSubst' droppedTysExpSubst) $
etaReductionError instanceType
return (instanceCxt, instanceType)
-- | Attempt to derive a constraint on a Type. If successful, return
-- Just the constraint and any kind variable names constrained to *.
-- Otherwise, return Nothing and the empty list.
--
-- See Note [Type inference in derived instances] for the heuristics used to
-- come up with constraints.
deriveConstraint :: ClassRep a => a -> Type -> (Maybe Pred, [Name])
deriveConstraint cRep t
| not (isTyVar t) = (Nothing, [])
| hasKindStar t = ((`applyClass` tName) `fmap` classConstraint cRep 0, [])
| otherwise = case hasKindVarChain 1 t of
Just ns | cRepArity >= 1
-> ((`applyClass` tName) `fmap` classConstraint cRep 1, ns)
_ -> case hasKindVarChain 2 t of
Just ns | cRepArity == 2
-> ((`applyClass` tName) `fmap` classConstraint cRep 2, ns)
_ -> (Nothing, [])
where
tName :: Name
tName = varTToName t
cRepArity :: Int
cRepArity = arity cRep
{-
Note [Kind signatures in derived instances]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
It is possible to put explicit kind signatures into the derived instances, e.g.,
instance C a => C (Data (f :: * -> *)) where ...
But it is preferable to avoid this if possible. If we come up with an incorrect
kind signature (which is entirely possible, since our type inferencer is pretty
unsophisticated - see Note [Type inference in derived instances]), then GHC will
flat-out reject the instance, which is quite unfortunate.
Plain old datatypes have the advantage that you can avoid using any kind signatures
at all in their instances. This is because a datatype declaration uses all type
variables, so the types that we use in a derived instance uniquely determine their
kinds. As long as we plug in the right types, the kind inferencer can do the rest
of the work. For this reason, we use unSigT to remove all kind signatures before
splicing in the instance context and head.
Data family instances are trickier, since a data family can have two instances that
are distinguished by kind alone, e.g.,
data family Fam (a :: k)
data instance Fam (a :: * -> *)
data instance Fam (a :: *)
If we dropped the kind signatures for C (Fam a), then GHC will have no way of
knowing which instance we are talking about. To avoid this scenario, we always
include explicit kind signatures in data family instances. There is a chance that
the inferred kind signatures will be incorrect, but if so, we can always fall back
on the make- functions.
Note [Type inference in derived instances]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Type inference is can be tricky to get right, and we want to avoid recreating the
entirety of GHC's type inferencer in Template Haskell. For this reason, we will
probably never come up with derived instance contexts that are as accurate as
GHC's. But that doesn't mean we can't do anything! There are a couple of simple
things we can do to make instance contexts that work for 80% of use cases:
1. If one of the last type parameters is polykinded, then its kind will be
specialized to * in the derived instance. We note what kind variable the type
parameter had and substitute it with * in the other types as well. For example,
imagine you had
data Data (a :: k) (b :: k)
Then you'd want to derived instance to be:
instance C (Data (a :: *))
Not:
instance C (Data (a :: k))
2. We naïvely come up with instance constraints using the following criteria, using
Show(1)(2) as the example typeclasses:
(i) If there's a type parameter n of kind *, generate a Show n constraint.
(ii) If there's a type parameter n of kind k1 -> k2 (where k1/k2 are * or kind
variables), then generate a Show1 n constraint, and if k1/k2 are kind
variables, then substitute k1/k2 with * elsewhere in the types. We must
consider the case where they are kind variables because you might have a
scenario like this:
newtype Compose (f :: k2 -> *) (g :: k1 -> k2) (a :: k1)
= Compose (f (g a))
Which would have a derived Show1 instance of:
instance (Show1 f, Show1 g) => Show1 (Compose f g) where ...
(iii) If there's a type parameter n of kind k1 -> k2 -> k3 (where k1/k2/k3 are
* or kind variables), then generate a Show2 constraint and perform
kind substitution as in the other cases.
-}
checkExistentialContext :: ClassRep a => a -> TyVarMap b -> Cxt -> Name
-> Q c -> Q c
checkExistentialContext cRep tvMap ctxt conName q =
if (any (`predMentionsName` Map.keys tvMap) ctxt
|| Map.size tvMap < arity cRep)
&& not (allowExQuant cRep)
then existentialContextError conName
else q
{-
Note [Matching functions with GADT type variables]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
When deriving category-2 classes like Show2, there is a tricky corner case to consider:
data Both a b where
BothCon :: x -> x -> Both x x
Which show functions should be applied to which arguments of BothCon? We have a
choice, since both the function of type (Int -> a -> ShowS) and of type
(Int -> b -> ShowS) can be applied to either argument. In such a scenario, the
second show function takes precedence over the first show function, so the
derived Show2 instance would be:
instance Show2 Both where
liftShowsPrec2 sp1 sp2 p (BothCon x1 x2) =
showsParen (p > appPrec) $
showString "BothCon " . sp2 appPrec1 x1 . showSpace . sp2 appPrec1 x2
This is not an arbitrary choice, as this definition ensures that
liftShowsPrec2 showsPrec = liftShowsPrec for a derived Show1 instance for
Both.
-}
-------------------------------------------------------------------------------
-- Error messages
-------------------------------------------------------------------------------
-- | The given datatype has no constructors, and we don't know what to do with it.
noConstructorsError :: Q a
noConstructorsError = fail "Must have at least one data constructor"
-- | Either the given data type doesn't have enough type variables, or one of
-- the type variables to be eta-reduced cannot realize kind *.
derivingKindError :: ClassRep a => a -> Name -> Q b
derivingKindError cRep tyConName = fail
. showString "Cannot derive well-kinded instance of form ‘"
. showString className
. showChar ' '
. showParen True
( showString (nameBase tyConName)
. showString " ..."
)
. showString "‘\n\tClass "
. showString className
. showString " expects an argument of kind "
. showString (pprint . createKindChain $ arity cRep)
$ ""
where
className :: String
className = nameBase $ fullClassName cRep
-- | The last type variable appeared in a contravariant position
-- when deriving Functor.
contravarianceError :: Name -> Q a
contravarianceError conName = fail
. showString "Constructor ‘"
. showString (nameBase conName)
. showString "‘ must not use the last type variable in a function argument"
$ ""
-- | A constructor has a function argument in a derived Foldable or Traversable
-- instance.
noFunctionsError :: Name -> Q a
noFunctionsError conName = fail
. showString "Constructor ‘"
. showString (nameBase conName)
. showString "‘ must not contain function types"
$ ""
-- | One of the last type variables cannot be eta-reduced (see the canEtaReduce
-- function for the criteria it would have to meet).
etaReductionError :: Type -> Q a
etaReductionError instanceType = fail $
"Cannot eta-reduce to an instance of form \n\tinstance (...) => "
++ pprint instanceType
-- | The data type has a DatatypeContext which mentions one of the eta-reduced
-- type variables.
datatypeContextError :: Name -> Type -> Q a
datatypeContextError dataName instanceType = fail
. showString "Can't make a derived instance of ‘"
. showString (pprint instanceType)
. showString "‘:\n\tData type ‘"
. showString (nameBase dataName)
. showString "‘ must not have a class context involving the last type argument(s)"
$ ""
-- | The data type has an existential constraint which mentions one of the
-- eta-reduced type variables.
existentialContextError :: Name -> Q a
existentialContextError conName = fail
. showString "Constructor ‘"
. showString (nameBase conName)
. showString "‘ must be truly polymorphic in the last argument(s) of the data type"
$ ""
-- | The data type mentions one of the n eta-reduced type variables in a place other
-- than the last nth positions of a data type in a constructor's field.
outOfPlaceTyVarError :: ClassRep a => a -> Name -> Q b
outOfPlaceTyVarError cRep conName = fail
. showString "Constructor ‘"
. showString (nameBase conName)
. showString "‘ must only use its last "
. shows n
. showString " type variable(s) within the last "
. shows n
. showString " argument(s) of a data type"
$ ""
where
n :: Int
n = arity cRep
enumerationError :: String -> Q a
enumerationError = fail . enumerationErrorStr
enumerationOrProductError :: String -> Q a
enumerationOrProductError nb = fail $ unlines
[ enumerationErrorStr nb
, "\tor a product type (precisely one constructor)"
]
enumerationErrorStr :: String -> String
enumerationErrorStr nb =
'\'':nb ++ "’ must be an enumeration type"
++ " (one or more nullary, non-GADT constructors)"
-------------------------------------------------------------------------------
-- Assorted utilities
-------------------------------------------------------------------------------
-- | A mapping of type variable Names to their auxiliary function Names.
type TyVarMap a = Map Name (OneOrTwoNames a)
type TyVarMap1 = TyVarMap One
type TyVarMap2 = TyVarMap Two
data OneOrTwoNames a where
OneName :: Name -> OneOrTwoNames One
TwoNames :: Name -> Name -> OneOrTwoNames Two
data One
data Two
interleave :: [a] -> [a] -> [a]
interleave (a1:a1s) (a2:a2s) = a1:a2:interleave a1s a2s
interleave _ _ = []
#if MIN_VERSION_ghc_prim(0,3,1)
isTrue# :: Int# -> Bool
isTrue# x = tagToEnum# x
#else
isTrue# :: Bool -> Bool
isTrue# x = x
#endif
{-# INLINE isTrue# #-}
-- isRight and fromEither taken from the extra package (BSD3-licensed)
-- | Test if an 'Either' value is the 'Right' constructor.
-- Provided as standard with GHC 7.8 and above.
isRight :: Either l r -> Bool
isRight Right{} = True; isRight _ = False
-- | Pull the value out of an 'Either' where both alternatives
-- have the same type.
--
-- > \x -> fromEither (Left x ) == x
-- > \x -> fromEither (Right x) == x
fromEither :: Either a a -> a
fromEither = either id id
-- filterByList, filterByLists, and partitionByList taken from GHC (BSD3-licensed)
-- | 'filterByList' takes a list of Bools and a list of some elements and
-- filters out these elements for which the corresponding value in the list of
-- Bools is False. This function does not check whether the lists have equal
-- length.
filterByList :: [Bool] -> [a] -> [a]
filterByList (True:bs) (x:xs) = x : filterByList bs xs
filterByList (False:bs) (_:xs) = filterByList bs xs
filterByList _ _ = []
-- | 'filterByLists' takes a list of Bools and two lists as input, and
-- outputs a new list consisting of elements from the last two input lists. For
-- each Bool in the list, if it is 'True', then it takes an element from the
-- former list. If it is 'False', it takes an element from the latter list.
-- The elements taken correspond to the index of the Bool in its list.
-- For example:
--
-- @
-- filterByLists [True, False, True, False] \"abcd\" \"wxyz\" = \"axcz\"
-- @
--
-- This function does not check whether the lists have equal length.
filterByLists :: [Bool] -> [a] -> [a] -> [a]
filterByLists (True:bs) (x:xs) (_:ys) = x : filterByLists bs xs ys
filterByLists (False:bs) (_:xs) (y:ys) = y : filterByLists bs xs ys
filterByLists _ _ _ = []
-- | 'partitionByList' takes a list of Bools and a list of some elements and
-- partitions the list according to the list of Bools. Elements corresponding
-- to 'True' go to the left; elements corresponding to 'False' go to the right.
-- For example, @partitionByList [True, False, True] [1,2,3] == ([1,3], [2])@
-- This function does not check whether the lists have equal
-- length.
partitionByList :: [Bool] -> [a] -> ([a], [a])
partitionByList = go [] []
where
go trues falses (True : bs) (x : xs) = go (x:trues) falses bs xs
go trues falses (False : bs) (x : xs) = go trues (x:falses) bs xs
go trues falses _ _ = (reverse trues, reverse falses)
-- | Apply an @Either Exp Exp@ expression to an 'Exp' expression,
-- preserving the 'Either'-ness.
appEitherE :: Q (Either Exp Exp) -> Q Exp -> Q (Either Exp Exp)
appEitherE e1Q e2Q = do
e2 <- e2Q
let e2' :: Exp -> Exp
e2' = (`AppE` e2)
either (Left . e2') (Right . e2') `fmap` e1Q
integerE :: Int -> Q Exp
integerE = litE . integerL . fromIntegral
-- | Returns True if a Type has kind *.
hasKindStar :: Type -> Bool
hasKindStar VarT{} = True
#if MIN_VERSION_template_haskell(2,8,0)
hasKindStar (SigT _ StarT) = True
#else
hasKindStar (SigT _ StarK) = True
#endif
hasKindStar _ = False
-- Returns True is a kind is equal to *, or if it is a kind variable.
isStarOrVar :: Kind -> Bool
#if MIN_VERSION_template_haskell(2,8,0)
isStarOrVar StarT = True
isStarOrVar VarT{} = True
#else
isStarOrVar StarK = True
#endif
isStarOrVar _ = False
-- | @hasKindVarChain n kind@ Checks if @kind@ is of the form
-- k_0 -> k_1 -> ... -> k_(n-1), where k0, k1, ..., and k_(n-1) can be * or
-- kind variables.
hasKindVarChain :: Int -> Type -> Maybe [Name]
hasKindVarChain kindArrows t =
let uk = uncurryKind (tyKind t)
in if (length uk - 1 == kindArrows) && all isStarOrVar uk
then Just (freeVariables uk)
else Nothing
-- | If a Type is a SigT, returns its kind signature. Otherwise, return *.
tyKind :: Type -> Kind
tyKind (SigT _ k) = k
tyKind _ = starK
zipWithAndUnzipM :: Monad m
=> (a -> b -> m (c, d)) -> [a] -> [b] -> m ([c], [d])
zipWithAndUnzipM f (x:xs) (y:ys) = do
(c, d) <- f x y
(cs, ds) <- zipWithAndUnzipM f xs ys
return (c:cs, d:ds)
zipWithAndUnzipM _ _ _ = return ([], [])
{-# INLINE zipWithAndUnzipM #-}
zipWith3AndUnzipM :: Monad m
=> (a -> b -> c -> m (d, e)) -> [a] -> [b] -> [c]
-> m ([d], [e])
zipWith3AndUnzipM f (x:xs) (y:ys) (z:zs) = do
(d, e) <- f x y z
(ds, es) <- zipWith3AndUnzipM f xs ys zs
return (d:ds, e:es)
zipWith3AndUnzipM _ _ _ _ = return ([], [])
{-# INLINE zipWith3AndUnzipM #-}
thd3 :: (a, b, c) -> c
thd3 (_, _, c) = c
unsnoc :: [a] -> Maybe ([a], a)
unsnoc [] = Nothing
unsnoc (x:xs) = case unsnoc xs of
Nothing -> Just ([], x)
Just (a,b) -> Just (x:a, b)
isNullaryCon :: ConstructorInfo -> Bool
isNullaryCon (ConstructorInfo { constructorFields = tys }) = null tys
-- | Returns the number of fields for the constructor.
conArity :: ConstructorInfo -> Int
conArity (ConstructorInfo { constructorFields = tys }) = length tys
-- | Returns 'True' if it's a datatype with exactly one, non-existential constructor.
isProductType :: [ConstructorInfo] -> Bool
isProductType [con] = null (constructorVars con)
isProductType _ = False
-- | Returns 'True' if it's a datatype with one or more nullary, non-GADT
-- constructors.
isEnumerationType :: [ConstructorInfo] -> Bool
isEnumerationType cons@(_:_) = all (liftA2 (&&) isNullaryCon isVanillaCon) cons
isEnumerationType _ = False
-- | Returns 'False' if we're dealing with existential quantification or GADTs.
isVanillaCon :: ConstructorInfo -> Bool
isVanillaCon (ConstructorInfo { constructorContext = ctxt, constructorVars = vars }) =
null ctxt && null vars
-- | Generate a list of fresh names with a common prefix, and numbered suffixes.
newNameList :: String -> Int -> Q [Name]
newNameList prefix n = mapM (newName . (prefix ++) . show) [1..n]
-- | Extracts the kind from a TyVarBndr.
tvbKind :: TyVarBndr -> Kind
tvbKind (PlainTV _) = starK
tvbKind (KindedTV _ k) = k
-- | Convert a TyVarBndr to a Type.
tvbToType :: TyVarBndr -> Type
tvbToType (PlainTV n) = VarT n
tvbToType (KindedTV n k) = SigT (VarT n) k
-- | Applies a typeclass constraint to a type.
applyClass :: Name -> Name -> Pred
#if MIN_VERSION_template_haskell(2,10,0)
applyClass con t = AppT (ConT con) (VarT t)
#else
applyClass con t = ClassP con [VarT t]
#endif
createKindChain :: Int -> Kind
createKindChain = go starK
where
go :: Kind -> Int -> Kind
go k !0 = k
#if MIN_VERSION_template_haskell(2,8,0)
go k !n = go (AppT (AppT ArrowT StarT) k) (n - 1)
#else
go k !n = go (ArrowK StarK k) (n - 1)
#endif
-- | Checks to see if the last types in a data family instance can be safely eta-
-- reduced (i.e., dropped), given the other types. This checks for three conditions:
--
-- (1) All of the dropped types are type variables
-- (2) All of the dropped types are distinct
-- (3) None of the remaining types mention any of the dropped types
canEtaReduce :: [Type] -> [Type] -> Bool
canEtaReduce remaining dropped =
all isTyVar dropped
&& allDistinct droppedNames -- Make sure not to pass something of type [Type], since Type
-- didn't have an Ord instance until template-haskell-2.10.0.0
&& not (any (`mentionsName` droppedNames) remaining)
where
droppedNames :: [Name]
droppedNames = map varTToName dropped
-- | Extract the Name from a type constructor. If the argument Type is not a
-- type variable, throw an error.
conTToName :: Type -> Name
conTToName (ConT n) = n
conTToName (SigT t _) = conTToName t
conTToName _ = error "Not a type constructor!"
-- | Extract Just the Name from a type variable. If the argument Type is not a
-- type variable, return Nothing.
varTToName_maybe :: Type -> Maybe Name
varTToName_maybe (VarT n) = Just n
varTToName_maybe (SigT t _) = varTToName_maybe t
varTToName_maybe _ = Nothing
-- | Extract the Name from a type variable. If the argument Type is not a
-- type variable, throw an error.
varTToName :: Type -> Name
varTToName = fromMaybe (error "Not a type variable!") . varTToName_maybe
-- | Peel off a kind signature from a Type (if it has one).
unSigT :: Type -> Type
unSigT (SigT t _) = t
unSigT t = t
-- | Is the given type a variable?
isTyVar :: Type -> Bool
isTyVar (VarT _) = True
isTyVar (SigT t _) = isTyVar t
isTyVar _ = False
-- | Is the given type a type family constructor (and not a data family constructor)?
isTyFamily :: Type -> Q Bool
isTyFamily (ConT n) = do
info <- reify n
return $ case info of
#if MIN_VERSION_template_haskell(2,11,0)
FamilyI OpenTypeFamilyD{} _ -> True
#elif MIN_VERSION_template_haskell(2,7,0)
FamilyI (FamilyD TypeFam _ _ _) _ -> True
#else
TyConI (FamilyD TypeFam _ _ _) -> True
#endif
#if MIN_VERSION_template_haskell(2,9,0)
FamilyI ClosedTypeFamilyD{} _ -> True
#endif
_ -> False
isTyFamily _ = return False
-- | Are all of the items in a list (which have an ordering) distinct?
--
-- This uses Set (as opposed to nub) for better asymptotic time complexity.
allDistinct :: Ord a => [a] -> Bool
allDistinct = allDistinct' Set.empty
where
allDistinct' :: Ord a => Set a -> [a] -> Bool
allDistinct' uniqs (x:xs)
| x `Set.member` uniqs = False
| otherwise = allDistinct' (Set.insert x uniqs) xs
allDistinct' _ _ = True
-- | Does the given type mention any of the Names in the list?
mentionsName :: Type -> [Name] -> Bool
mentionsName = go
where
go :: Type -> [Name] -> Bool
go (AppT t1 t2) names = go t1 names || go t2 names
go (SigT t _k) names = go t names
#if MIN_VERSION_template_haskell(2,8,0)
|| go _k names
#endif
go (VarT n) names = n `elem` names
go _ _ = False
-- | Does an instance predicate mention any of the Names in the list?
predMentionsName :: Pred -> [Name] -> Bool
#if MIN_VERSION_template_haskell(2,10,0)
predMentionsName = mentionsName
#else
predMentionsName (ClassP n tys) names = n `elem` names || any (`mentionsName` names) tys
predMentionsName (EqualP t1 t2) names = mentionsName t1 names || mentionsName t2 names
#endif
-- | Construct a type via curried application.
applyTy :: Type -> [Type] -> Type
applyTy = foldl' AppT
-- | Fully applies a type constructor to its type variables.
applyTyCon :: Name -> [Type] -> Type
applyTyCon = applyTy . ConT
-- | Split an applied type into its individual components. For example, this:
--
-- @
-- Either Int Char
-- @
--
-- would split to this:
--
-- @
-- [Either, Int, Char]
-- @
unapplyTy :: Type -> [Type]
unapplyTy = reverse . go
where
go :: Type -> [Type]
go (AppT t1 t2) = t2:go t1
go (SigT t _) = go t
go (ForallT _ _ t) = go t
go t = [t]
-- | Split a type signature by the arrows on its spine. For example, this:
--
-- @
-- forall a b. (a ~ b) => (a -> b) -> Char -> ()
-- @
--
-- would split to this:
--
-- @
-- (a ~ b, [a -> b, Char, ()])
-- @
uncurryTy :: Type -> (Cxt, [Type])
uncurryTy (AppT (AppT ArrowT t1) t2) =
let (ctxt, tys) = uncurryTy t2
in (ctxt, t1:tys)
uncurryTy (SigT t _) = uncurryTy t
uncurryTy (ForallT _ ctxt t) =
let (ctxt', tys) = uncurryTy t
in (ctxt ++ ctxt', tys)
uncurryTy t = ([], [t])
-- | Like uncurryType, except on a kind level.
uncurryKind :: Kind -> [Kind]
#if MIN_VERSION_template_haskell(2,8,0)
uncurryKind = snd . uncurryTy
#else
uncurryKind (ArrowK k1 k2) = k1:uncurryKind k2
uncurryKind k = [k]
#endif
untagExpr :: [(Name, Name)] -> Q Exp -> Q Exp
untagExpr [] e = e
untagExpr ((untagThis, putTagHere) : more) e =
caseE (varE getTagValName `appE` varE untagThis)
[match (varP putTagHere)
(normalB $ untagExpr more e)
[]]
tag2ConExpr :: Type -> Q Exp
tag2ConExpr ty = do
iHash <- newName "i#"
ty' <- freshenType ty
lam1E (conP iHashDataName [varP iHash]) $
varE tagToEnumHashValName `appE` varE iHash
`sigE` return (ForallT (requiredTyVarsOfType ty') [] ty')
-- tagToEnum# is a hack, and won't typecheck unless it's in the
-- immediate presence of a type ascription like so:
--
-- tagToEnum# x :: Foo
--
-- We have to be careful when dealing with datatypes with type
-- variables, since Template Haskell might reject the type variables
-- we use for being out-of-scope. To avoid this, we explicitly
-- collect the type variable binders with requiredTyVarsOfType
-- and shove them into a ForallT. Also make sure to freshen the
-- bound type variables to avoid shadowed variable warnings when
-- -Wall is enabled.
--
-- Note that we do NOT collect the kind variable binders, since
-- a type signature like `forall k a. Foo (a :: k)` won't typecheck
-- unless TypeInType is enabled (i.e., if GHC 8.0 or later is being
-- used). Luckily, GHC seems to just accept kind variables, even if
-- they aren't actually bound in a ForallT.
removeClassApp :: Type -> Type
removeClassApp (AppT _ t2) = t2
removeClassApp t = t
-- This is an ugly, but unfortunately necessary hack on older versions of GHC which
-- don't have a properly working newName. On those GHCs, even running newName on a
-- variable isn't enought to avoid shadowed variable warnings, so we "fix" the issue by
-- appending an uncommonly used string to the end of the name. This isn't foolproof,
-- since a user could freshen a variable named x and still have another x_' variable in
-- scope, but at least it's unlikely.
freshen :: Name -> Q Name
freshen n = newName (nameBase n ++ "_'")
freshenType :: Type -> Q Type
freshenType (AppT t1 t2) = do t1' <- freshenType t1
t2' <- freshenType t2
return $ AppT t1' t2'
freshenType (SigT t k) = do t' <- freshenType t
return $ SigT t' k
freshenType (VarT n) = fmap VarT $ freshen n
freshenType t = return t
-- | Gets all of the required type variable binders mentioned in a Type.
requiredTyVarsOfType :: Type -> [TyVarBndr]
requiredTyVarsOfType = go
where
go :: Type -> [TyVarBndr]
go (AppT t1 t2) = go t1 ++ go t2
go (SigT t _) = go t
go (VarT n) = [PlainTV n]
go _ = []
enumFromToExpr :: Q Exp -> Q Exp -> Q Exp
enumFromToExpr f t = varE enumFromToValName `appE` f `appE` t
primOpAppExpr :: Q Exp -> Name -> Q Exp -> Q Exp
primOpAppExpr e1 op e2 = varE isTrueHashValName `appE`
infixApp e1 (varE op) e2
-- | Checks if a 'Name' represents a tuple type constructor (other than '()')
isNonUnitTuple :: Name -> Bool
isNonUnitTuple = isNonUnitTupleString . nameBase
-- | Checks if a 'String' represents a tuple (other than '()')
isNonUnitTupleString :: String -> Bool
isNonUnitTupleString ('(':',':_) = True
isNonUnitTupleString _ = False
-- | Checks if a 'String' names a valid Haskell infix data constructor (i.e., does
-- it begin with a colon?).
isInfixDataCon :: String -> Bool
isInfixDataCon (':':_) = True
isInfixDataCon _ = False
isSym :: String -> Bool
isSym "" = False
isSym (c : _) = startsVarSym c || startsConSym c
#if !defined(MIN_VERSION_ghc_boot_th)
startsVarSym, startsConSym :: Char -> Bool
startsVarSym c = startsVarSymASCII c || (ord c > 0x7f && isSymbol c) -- Infix Ids
startsConSym c = c == ':' -- Infix data constructors
startsVarSymASCII :: Char -> Bool
startsVarSymASCII c = c `elem` "!#$%&*+./<=>?@\\^|~-"
#endif
ghc7'8OrLater :: Bool
#if __GLASGOW_HASKELL__ >= 708
ghc7'8OrLater = True
#else
ghc7'8OrLater = False
#endif
-------------------------------------------------------------------------------
-- Manually quoted names
-------------------------------------------------------------------------------
-- By manually generating these names we avoid needing to use the
-- TemplateHaskell language extension when compiling the deriving-compat library.
-- This allows the library to be used in stage1 cross-compilers.
derivingCompatPackageKey :: String
#ifdef CURRENT_PACKAGE_KEY
derivingCompatPackageKey = CURRENT_PACKAGE_KEY
#else
derivingCompatPackageKey = "deriving-compat-" ++ showVersion version
#endif
mkDerivingCompatName_v :: String -> Name
mkDerivingCompatName_v = mkNameG_v derivingCompatPackageKey "Data.Deriving.Internal"
mkDerivingCompatName_tc :: String -> Name
mkDerivingCompatName_tc = mkNameG_tc derivingCompatPackageKey "Data.Deriving.Internal"
isTrueHashValName :: Name
isTrueHashValName = mkDerivingCompatName_v "isTrue#"
fmapConstValName :: Name
fmapConstValName = mkDerivingCompatName_v "fmapConst"
foldrConstValName :: Name
foldrConstValName = mkDerivingCompatName_v "foldrConst"
foldMapConstValName :: Name
foldMapConstValName = mkDerivingCompatName_v "foldMapConst"
traverseConstValName :: Name
traverseConstValName = mkDerivingCompatName_v "traverseConst"
eqConstValName :: Name
eqConstValName = mkDerivingCompatName_v "eqConst"
eq1ConstValName :: Name
eq1ConstValName = mkDerivingCompatName_v "eq1Const"
liftEqConstValName :: Name
liftEqConstValName = mkDerivingCompatName_v "liftEqConst"
liftEq2ConstValName :: Name
liftEq2ConstValName = mkDerivingCompatName_v "liftEq2Const"
compareConstValName :: Name
compareConstValName = mkDerivingCompatName_v "compareConst"
ltConstValName :: Name
ltConstValName = mkDerivingCompatName_v "ltConst"
compare1ConstValName :: Name
compare1ConstValName = mkDerivingCompatName_v "compare1Const"
liftCompareConstValName :: Name
liftCompareConstValName = mkDerivingCompatName_v "liftCompareConst"
liftCompare2ConstValName :: Name
liftCompare2ConstValName = mkDerivingCompatName_v "liftCompare2Const"
readsPrecConstValName :: Name
readsPrecConstValName = mkDerivingCompatName_v "readsPrecConst"
readPrecConstValName :: Name
readPrecConstValName = mkDerivingCompatName_v "readPrecConst"
readsPrec1ConstValName :: Name
readsPrec1ConstValName = mkDerivingCompatName_v "readsPrec1Const"
liftReadsPrecConstValName :: Name
liftReadsPrecConstValName = mkDerivingCompatName_v "liftReadsPrecConst"
liftReadPrecConstValName :: Name
liftReadPrecConstValName = mkDerivingCompatName_v "liftReadPrecConst"
liftReadsPrec2ConstValName :: Name
liftReadsPrec2ConstValName = mkDerivingCompatName_v "liftReadsPrec2Const"
liftReadPrec2ConstValName :: Name
liftReadPrec2ConstValName = mkDerivingCompatName_v "liftReadPrec2Const"
showsPrecConstValName :: Name
showsPrecConstValName = mkDerivingCompatName_v "showsPrecConst"
showsPrec1ConstValName :: Name
showsPrec1ConstValName = mkDerivingCompatName_v "showsPrec1Const"
liftShowsPrecConstValName :: Name
liftShowsPrecConstValName = mkDerivingCompatName_v "liftShowsPrecConst"
liftShowsPrec2ConstValName :: Name
liftShowsPrec2ConstValName = mkDerivingCompatName_v "liftShowsPrec2Const"
viaTypeName :: Name
viaTypeName = mkDerivingCompatName_tc "Via"
cHashDataName :: Name
cHashDataName = mkNameG_d "ghc-prim" "GHC.Types" "C#"
dHashDataName :: Name
dHashDataName = mkNameG_d "ghc-prim" "GHC.Types" "D#"
fHashDataName :: Name
fHashDataName = mkNameG_d "ghc-prim" "GHC.Types" "F#"
identDataName :: Name
identDataName = mkNameG_d "base" "Text.Read.Lex" "Ident"
iHashDataName :: Name
iHashDataName = mkNameG_d "ghc-prim" "GHC.Types" "I#"
puncDataName :: Name
puncDataName = mkNameG_d "base" "Text.Read.Lex" "Punc"
symbolDataName :: Name
symbolDataName = mkNameG_d "base" "Text.Read.Lex" "Symbol"
wrapMonadDataName :: Name
wrapMonadDataName = mkNameG_d "base" "Control.Applicative" "WrapMonad"
addrHashTypeName :: Name
addrHashTypeName = mkNameG_tc "ghc-prim" "GHC.Prim" "Addr#"
boundedTypeName :: Name
boundedTypeName = mkNameG_tc "base" "GHC.Enum" "Bounded"
charHashTypeName :: Name
charHashTypeName = mkNameG_tc "ghc-prim" "GHC.Prim" "Char#"
doubleHashTypeName :: Name
doubleHashTypeName = mkNameG_tc "ghc-prim" "GHC.Prim" "Double#"
enumTypeName :: Name
enumTypeName = mkNameG_tc "base" "GHC.Enum" "Enum"
floatHashTypeName :: Name
floatHashTypeName = mkNameG_tc "ghc-prim" "GHC.Prim" "Float#"
foldableTypeName :: Name
foldableTypeName = mkNameG_tc "base" "Data.Foldable" "Foldable"
functorTypeName :: Name
functorTypeName = mkNameG_tc "base" "GHC.Base" "Functor"
intTypeName :: Name
intTypeName = mkNameG_tc "ghc-prim" "GHC.Types" "Int"
intHashTypeName :: Name
intHashTypeName = mkNameG_tc "ghc-prim" "GHC.Prim" "Int#"
ixTypeName :: Name
ixTypeName = mkNameG_tc "base" "GHC.Arr" "Ix"
readTypeName :: Name
readTypeName = mkNameG_tc "base" "GHC.Read" "Read"
showTypeName :: Name
showTypeName = mkNameG_tc "base" "GHC.Show" "Show"
traversableTypeName :: Name
traversableTypeName = mkNameG_tc "base" "Data.Traversable" "Traversable"
wordHashTypeName :: Name
wordHashTypeName = mkNameG_tc "ghc-prim" "GHC.Prim" "Word#"
altValName :: Name
altValName = mkNameG_v "base" "Text.ParserCombinators.ReadPrec" "+++"
appendValName :: Name
appendValName = mkNameG_v "base" "GHC.Base" "++"
chooseValName :: Name
chooseValName = mkNameG_v "base" "GHC.Read" "choose"
coerceValName :: Name
coerceValName = mkNameG_v "ghc-prim" "GHC.Prim" "coerce"
composeValName :: Name
composeValName = mkNameG_v "base" "GHC.Base" "."
constValName :: Name
constValName = mkNameG_v "base" "GHC.Base" "const"
enumFromValName :: Name
enumFromValName = mkNameG_v "base" "GHC.Enum" "enumFrom"
enumFromThenValName :: Name
enumFromThenValName = mkNameG_v "base" "GHC.Enum" "enumFromThen"
enumFromThenToValName :: Name
enumFromThenToValName = mkNameG_v "base" "GHC.Enum" "enumFromThenTo"
enumFromToValName :: Name
enumFromToValName = mkNameG_v "base" "GHC.Enum" "enumFromTo"
eqAddrHashValName :: Name
eqAddrHashValName = mkNameG_v "ghc-prim" "GHC.Prim" "eqAddr#"
eqCharHashValName :: Name
eqCharHashValName = mkNameG_v "ghc-prim" "GHC.Prim" "eqChar#"
eqDoubleHashValName :: Name
eqDoubleHashValName = mkNameG_v "ghc-prim" "GHC.Prim" "==##"
eqFloatHashValName :: Name
eqFloatHashValName = mkNameG_v "ghc-prim" "GHC.Prim" "eqFloat#"
eqIntHashValName :: Name
eqIntHashValName = mkNameG_v "ghc-prim" "GHC.Prim" "==#"
eqWordHashValName :: Name
eqWordHashValName = mkNameG_v "ghc-prim" "GHC.Prim" "eqWord#"
errorValName :: Name
errorValName = mkNameG_v "base" "GHC.Err" "error"
flipValName :: Name
flipValName = mkNameG_v "base" "GHC.Base" "flip"
fmapValName :: Name
fmapValName = mkNameG_v "base" "GHC.Base" "fmap"
foldrValName :: Name
foldrValName = mkNameG_v "base" "Data.Foldable" "foldr"
foldMapValName :: Name
foldMapValName = mkNameG_v "base" "Data.Foldable" "foldMap"
fromEnumValName :: Name
fromEnumValName = mkNameG_v "base" "GHC.Enum" "fromEnum"
geAddrHashValName :: Name
geAddrHashValName = mkNameG_v "ghc-prim" "GHC.Prim" "geAddr#"
geCharHashValName :: Name
geCharHashValName = mkNameG_v "ghc-prim" "GHC.Prim" "geChar#"
geDoubleHashValName :: Name
geDoubleHashValName = mkNameG_v "ghc-prim" "GHC.Prim" ">=##"
geFloatHashValName :: Name
geFloatHashValName = mkNameG_v "ghc-prim" "GHC.Prim" "geFloat#"
geIntHashValName :: Name
geIntHashValName = mkNameG_v "ghc-prim" "GHC.Prim" ">=#"
getTagValName :: Name
getTagValName = mkNameG_v "base" "GHC.Base" "getTag"
geWordHashValName :: Name
geWordHashValName = mkNameG_v "ghc-prim" "GHC.Prim" "geWord#"
gtAddrHashValName :: Name
gtAddrHashValName = mkNameG_v "ghc-prim" "GHC.Prim" "gtAddr#"
gtCharHashValName :: Name
gtCharHashValName = mkNameG_v "ghc-prim" "GHC.Prim" "gtChar#"
gtDoubleHashValName :: Name
gtDoubleHashValName = mkNameG_v "ghc-prim" "GHC.Prim" ">##"
gtFloatHashValName :: Name
gtFloatHashValName = mkNameG_v "ghc-prim" "GHC.Prim" "gtFloat#"
gtIntHashValName :: Name
gtIntHashValName = mkNameG_v "ghc-prim" "GHC.Prim" ">#"
gtWordHashValName :: Name
gtWordHashValName = mkNameG_v "ghc-prim" "GHC.Prim" "gtWord#"
idValName :: Name
idValName = mkNameG_v "base" "GHC.Base" "id"
indexValName :: Name
indexValName = mkNameG_v "base" "GHC.Arr" "index"
inRangeValName :: Name
inRangeValName = mkNameG_v "base" "GHC.Arr" "inRange"
leAddrHashValName :: Name
leAddrHashValName = mkNameG_v "ghc-prim" "GHC.Prim" "leAddr#"
leCharHashValName :: Name
leCharHashValName = mkNameG_v "ghc-prim" "GHC.Prim" "leChar#"
leDoubleHashValName :: Name
leDoubleHashValName = mkNameG_v "ghc-prim" "GHC.Prim" "<=##"
leFloatHashValName :: Name
leFloatHashValName = mkNameG_v "ghc-prim" "GHC.Prim" "leFloat#"
leIntHashValName :: Name
leIntHashValName = mkNameG_v "ghc-prim" "GHC.Prim" "<=#"
leWordHashValName :: Name
leWordHashValName = mkNameG_v "ghc-prim" "GHC.Prim" "leWord#"
liftReadListPrecDefaultValName :: Name
liftReadListPrecDefaultValName = mkNameG_v "base" "Data.Functor.Classes" "liftReadListPrecDefault"
liftReadListPrec2DefaultValName :: Name
liftReadListPrec2DefaultValName = mkNameG_v "base" "Data.Functor.Classes" "liftReadListPrec2Default"
liftReadListPrecValName :: Name
liftReadListPrecValName = mkNameG_v "base" "Data.Functor.Classes" "liftReadListPrec"
liftReadListPrec2ValName :: Name
liftReadListPrec2ValName = mkNameG_v "base" "Data.Functor.Classes" "liftReadListPrec2"
liftReadPrecValName :: Name
liftReadPrecValName = mkNameG_v "base" "Data.Functor.Classes" "liftReadPrec"
liftReadPrec2ValName :: Name
liftReadPrec2ValName = mkNameG_v "base" "Data.Functor.Classes" "liftReadPrec2"
listValName :: Name
listValName = mkNameG_v "base" "GHC.Read" "list"
ltAddrHashValName :: Name
ltAddrHashValName = mkNameG_v "ghc-prim" "GHC.Prim" "ltAddr#"
ltCharHashValName :: Name
ltCharHashValName = mkNameG_v "ghc-prim" "GHC.Prim" "ltChar#"
ltDoubleHashValName :: Name
ltDoubleHashValName = mkNameG_v "ghc-prim" "GHC.Prim" "<##"
ltFloatHashValName :: Name
ltFloatHashValName = mkNameG_v "ghc-prim" "GHC.Prim" "ltFloat#"
ltIntHashValName :: Name
ltIntHashValName = mkNameG_v "ghc-prim" "GHC.Prim" "<#"
ltWordHashValName :: Name
ltWordHashValName = mkNameG_v "ghc-prim" "GHC.Prim" "ltWord#"
minBoundValName :: Name
minBoundValName = mkNameG_v "base" "GHC.Enum" "minBound"
mapValName :: Name
mapValName = mkNameG_v "base" "GHC.Base" "map"
maxBoundValName :: Name
maxBoundValName = mkNameG_v "base" "GHC.Enum" "maxBound"
minusIntHashValName :: Name
minusIntHashValName = mkNameG_v "ghc-prim" "GHC.Prim" "-#"
parenValName :: Name
parenValName = mkNameG_v "base" "GHC.Read" "paren"
parensValName :: Name
parensValName = mkNameG_v "base" "GHC.Read" "parens"
pfailValName :: Name
pfailValName = mkNameG_v "base" "Text.ParserCombinators.ReadPrec" "pfail"
plusValName :: Name
plusValName = mkNameG_v "base" "GHC.Num" "+"
precValName :: Name
precValName = mkNameG_v "base" "Text.ParserCombinators.ReadPrec" "prec"
predValName :: Name
predValName = mkNameG_v "base" "GHC.Enum" "pred"
rangeSizeValName :: Name
rangeSizeValName = mkNameG_v "base" "GHC.Arr" "rangeSize"
rangeValName :: Name
rangeValName = mkNameG_v "base" "GHC.Arr" "range"
readFieldHash :: String -> ReadPrec a -> ReadPrec a
readFieldHash fieldName readVal = do
expectP (L.Ident fieldName)
expectP (L.Symbol "#")
expectP (L.Punc "=")
readVal
{-# NOINLINE readFieldHash #-}
readFieldHashValName :: Name
readFieldHashValName = mkNameG_v derivingCompatPackageKey "Data.Deriving.Internal" "readFieldHash"
readListValName :: Name
readListValName = mkNameG_v "base" "GHC.Read" "readList"
readListPrecDefaultValName :: Name
readListPrecDefaultValName = mkNameG_v "base" "GHC.Read" "readListPrecDefault"
readListPrecValName :: Name
readListPrecValName = mkNameG_v "base" "GHC.Read" "readListPrec"
readPrec_to_SValName :: Name
readPrec_to_SValName = mkNameG_v "base" "Text.ParserCombinators.ReadPrec" "readPrec_to_S"
readPrecValName :: Name
readPrecValName = mkNameG_v "base" "GHC.Read" "readPrec"
readS_to_PrecValName :: Name
readS_to_PrecValName = mkNameG_v "base" "Text.ParserCombinators.ReadPrec" "readS_to_Prec"
readsPrecValName :: Name
readsPrecValName = mkNameG_v "base" "GHC.Read" "readsPrec"
resetValName :: Name
resetValName = mkNameG_v "base" "Text.ParserCombinators.ReadPrec" "reset"
returnValName :: Name
returnValName = mkNameG_v "base" "GHC.Base" "return"
seqValName :: Name
seqValName = mkNameG_v "ghc-prim" "GHC.Prim" "seq"
showCharValName :: Name
showCharValName = mkNameG_v "base" "GHC.Show" "showChar"
showListValName :: Name
showListValName = mkNameG_v "base" "GHC.Show" "showList"
showListWithValName :: Name
showListWithValName = mkNameG_v "base" "Text.Show" "showListWith"
showParenValName :: Name
showParenValName = mkNameG_v "base" "GHC.Show" "showParen"
showsPrecValName :: Name
showsPrecValName = mkNameG_v "base" "GHC.Show" "showsPrec"
showSpaceValName :: Name
showSpaceValName = mkNameG_v "base" "GHC.Show" "showSpace"
showStringValName :: Name
showStringValName = mkNameG_v "base" "GHC.Show" "showString"
stepValName :: Name
stepValName = mkNameG_v "base" "Text.ParserCombinators.ReadPrec" "step"
succValName :: Name
succValName = mkNameG_v "base" "GHC.Enum" "succ"
tagToEnumHashValName :: Name
tagToEnumHashValName = mkNameG_v "ghc-prim" "GHC.Prim" "tagToEnum#"
timesValName :: Name
timesValName = mkNameG_v "base" "GHC.Num" "*"
toEnumValName :: Name
toEnumValName = mkNameG_v "base" "GHC.Enum" "toEnum"
traverseValName :: Name
traverseValName = mkNameG_v "base" "Data.Traversable" "traverse"
unsafeIndexValName :: Name
unsafeIndexValName = mkNameG_v "base" "GHC.Arr" "unsafeIndex"
unsafeRangeSizeValName :: Name
unsafeRangeSizeValName = mkNameG_v "base" "GHC.Arr" "unsafeRangeSize"
unwrapMonadValName :: Name
unwrapMonadValName = mkNameG_v "base" "Control.Applicative" "unwrapMonad"
#if MIN_VERSION_base(4,4,0)
boolTypeName :: Name
boolTypeName = mkNameG_tc "ghc-prim" "GHC.Types" "Bool"
falseDataName :: Name
falseDataName = mkNameG_v "ghc-prim" "GHC.Types" "False"
trueDataName :: Name
trueDataName = mkNameG_v "ghc-prim" "GHC.Types" "True"
#else
boolTypeName :: Name
boolTypeName = mkNameG_tc "ghc-prim" "GHC.Bool" "Bool"
falseDataName :: Name
falseDataName = mkNameG_v "ghc-prim" "GHC.Bool" "False"
trueDataName :: Name
trueDataName = mkNameG_v "ghc-prim" "GHC.Bool" "True"
#endif
#if MIN_VERSION_base(4,5,0)
eqDataName :: Name
eqDataName = mkNameG_d "ghc-prim" "GHC.Types" "EQ"
gtDataName :: Name
gtDataName = mkNameG_d "ghc-prim" "GHC.Types" "GT"
ltDataName :: Name
ltDataName = mkNameG_d "ghc-prim" "GHC.Types" "LT"
eqTypeName :: Name
eqTypeName = mkNameG_tc "ghc-prim" "GHC.Classes" "Eq"
ordTypeName :: Name
ordTypeName = mkNameG_tc "ghc-prim" "GHC.Classes" "Ord"
andValName :: Name
andValName = mkNameG_v "ghc-prim" "GHC.Classes" "&&"
compareValName :: Name
compareValName = mkNameG_v "ghc-prim" "GHC.Classes" "compare"
eqValName :: Name
eqValName = mkNameG_v "ghc-prim" "GHC.Classes" "=="
geValName :: Name
geValName = mkNameG_v "ghc-prim" "GHC.Classes" ">="
gtValName :: Name
gtValName = mkNameG_v "ghc-prim" "GHC.Classes" ">"
leValName :: Name
leValName = mkNameG_v "ghc-prim" "GHC.Classes" "<="
ltValName :: Name
ltValName = mkNameG_v "ghc-prim" "GHC.Classes" "<"
notValName :: Name
notValName = mkNameG_v "ghc-prim" "GHC.Classes" "not"
#else
eqDataName :: Name
eqDataName = mkNameG_d "ghc-prim" "GHC.Ordering" "EQ"
gtDataName :: Name
gtDataName = mkNameG_d "ghc-prim" "GHC.Ordering" "GT"
ltDataName :: Name
ltDataName = mkNameG_d "ghc-prim" "GHC.Ordering" "LT"
eqTypeName :: Name
eqTypeName = mkNameG_tc "base" "GHC.Classes" "Eq"
ordTypeName :: Name
ordTypeName = mkNameG_tc "base" "GHC.Classes" "Ord"
andValName :: Name
andValName = mkNameG_v "base" "GHC.Classes" "&&"
compareValName :: Name
compareValName = mkNameG_v "base" "GHC.Classes" "compare"
eqValName :: Name
eqValName = mkNameG_v "base" "GHC.Classes" "=="
geValName :: Name
geValName = mkNameG_v "base" "GHC.Classes" ">="
gtValName :: Name
gtValName = mkNameG_v "base" "GHC.Classes" ">"
leValName :: Name
leValName = mkNameG_v "base" "GHC.Classes" "<="
ltValName :: Name
ltValName = mkNameG_v "base" "GHC.Classes" "<"
notValName :: Name
notValName = mkNameG_v "base" "GHC.Classes" "not"
#endif
#if MIN_VERSION_base(4,6,0)
wHashDataName :: Name
wHashDataName = mkNameG_d "ghc-prim" "GHC.Types" "W#"
#else
wHashDataName :: Name
wHashDataName = mkNameG_d "base" "GHC.Word" "W#"
#endif
#if MIN_VERSION_base(4,6,0) && !(MIN_VERSION_base(4,9,0))
starKindName :: Name
starKindName = mkNameG_tc "ghc-prim" "GHC.Prim" "*"
#endif
#if MIN_VERSION_base(4,7,0)
expectPValName :: Name
expectPValName = mkNameG_v "base" "GHC.Read" "expectP"
#else
expectP :: Lexeme -> ReadPrec ()
expectP lexeme = do
thing <- lexP
if thing == lexeme then return () else pfail
expectPValName :: Name
expectPValName = mkDerivingCompatName_v "expectP"
#endif
#if MIN_VERSION_base(4,8,0)
pureValName :: Name
pureValName = mkNameG_v "base" "GHC.Base" "pure"
apValName :: Name
apValName = mkNameG_v "base" "GHC.Base" "<*>"
liftA2ValName :: Name
liftA2ValName = mkNameG_v "base" "GHC.Base" "liftA2"
mappendValName :: Name
mappendValName = mkNameG_v "base" "GHC.Base" "mappend"
memptyValName :: Name
memptyValName = mkNameG_v "base" "GHC.Base" "mempty"
#else
pureValName :: Name
pureValName = mkNameG_v "base" "Control.Applicative" "pure"
apValName :: Name
apValName = mkNameG_v "base" "Control.Applicative" "<*>"
liftA2ValName :: Name
liftA2ValName = mkNameG_v "base" "Control.Applicative" "liftA2"
mappendValName :: Name
mappendValName = mkNameG_v "base" "Data.Monoid" "mappend"
memptyValName :: Name
memptyValName = mkNameG_v "base" "Data.Monoid" "mempty"
#endif
#if MIN_VERSION_base(4,9,0)
eq1TypeName :: Name
eq1TypeName = mkNameG_tc "base" "Data.Functor.Classes" "Eq1"
eq2TypeName :: Name
eq2TypeName = mkNameG_tc "base" "Data.Functor.Classes" "Eq2"
liftEqValName :: Name
liftEqValName = mkNameG_v "base" "Data.Functor.Classes" "liftEq"
liftEq2ValName :: Name
liftEq2ValName = mkNameG_v "base" "Data.Functor.Classes" "liftEq2"
ord1TypeName :: Name
ord1TypeName = mkNameG_tc "base" "Data.Functor.Classes" "Ord1"
ord2TypeName :: Name
ord2TypeName = mkNameG_tc "base" "Data.Functor.Classes" "Ord2"
liftCompareValName :: Name
liftCompareValName = mkNameG_v "base" "Data.Functor.Classes" "liftCompare"
liftCompare2ValName :: Name
liftCompare2ValName = mkNameG_v "base" "Data.Functor.Classes" "liftCompare2"
read1TypeName :: Name
read1TypeName = mkNameG_tc "base" "Data.Functor.Classes" "Read1"
read2TypeName :: Name
read2TypeName = mkNameG_tc "base" "Data.Functor.Classes" "Read2"
liftReadsPrecValName :: Name
liftReadsPrecValName = mkNameG_v "base" "Data.Functor.Classes" "liftReadsPrec"
liftReadListValName :: Name
liftReadListValName = mkNameG_v "base" "Data.Functor.Classes" "liftReadList"
liftReadsPrec2ValName :: Name
liftReadsPrec2ValName = mkNameG_v "base" "Data.Functor.Classes" "liftReadsPrec2"
liftReadList2ValName :: Name
liftReadList2ValName = mkNameG_v "base" "Data.Functor.Classes" "liftReadList2"
show1TypeName :: Name
show1TypeName = mkNameG_tc "base" "Data.Functor.Classes" "Show1"
show2TypeName :: Name
show2TypeName = mkNameG_tc "base" "Data.Functor.Classes" "Show2"
liftShowListValName :: Name
liftShowListValName = mkNameG_v "base" "Data.Functor.Classes" "liftShowList"
liftShowsPrecValName :: Name
liftShowsPrecValName = mkNameG_v "base" "Data.Functor.Classes" "liftShowsPrec"
liftShowList2ValName :: Name
liftShowList2ValName = mkNameG_v "base" "Data.Functor.Classes" "liftShowList2"
liftShowsPrec2ValName :: Name
liftShowsPrec2ValName = mkNameG_v "base" "Data.Functor.Classes" "liftShowsPrec2"
#else
-- If Data.Functor.Classes isn't located in base, then sadly we can't refer to
-- Names from that module without using -XTemplateHaskell.
# if !(MIN_VERSION_transformers(0,4,0)) || MIN_VERSION_transformers(0,5,0)
eq1TypeName :: Name
eq1TypeName = ''Eq1
eq2TypeName :: Name
eq2TypeName = ''Eq2
liftEqValName :: Name
liftEqValName = 'liftEq
liftEq2ValName :: Name
liftEq2ValName = 'liftEq2
ord1TypeName :: Name
ord1TypeName = ''Ord1
ord2TypeName :: Name
ord2TypeName = ''Ord2
liftCompareValName :: Name
liftCompareValName = 'liftCompare
liftCompare2ValName :: Name
liftCompare2ValName = 'liftCompare2
read1TypeName :: Name
read1TypeName = ''Read1
read2TypeName :: Name
read2TypeName = ''Read2
liftReadsPrecValName :: Name
liftReadsPrecValName = 'liftReadsPrec
liftReadListValName :: Name
liftReadListValName = 'liftReadList
liftReadsPrec2ValName :: Name
liftReadsPrec2ValName = 'liftReadsPrec2
liftReadList2ValName :: Name
liftReadList2ValName = 'liftReadList2
show1TypeName :: Name
show1TypeName = ''Show1
show2TypeName :: Name
show2TypeName = ''Show2
liftShowListValName :: Name
liftShowListValName = 'liftShowList
liftShowsPrecValName :: Name
liftShowsPrecValName = 'liftShowsPrec
liftShowList2ValName :: Name
liftShowList2ValName = 'liftShowList2
liftShowsPrec2ValName :: Name
liftShowsPrec2ValName = 'liftShowsPrec2
# else
eq1TypeName :: Name
eq1TypeName = ''Eq1
eq1ValName :: Name
eq1ValName = 'eq1
ord1TypeName :: Name
ord1TypeName = ''Ord1
compare1ValName :: Name
compare1ValName = 'compare1
read1TypeName :: Name
read1TypeName = ''Read1
readsPrec1ValName :: Name
readsPrec1ValName = 'readsPrec1
show1TypeName :: Name
show1TypeName = ''Show1
showsPrec1ValName :: Name
showsPrec1ValName = 'showsPrec1
newtype Apply f a = Apply { unApply :: f a }
instance (Eq1 f, Eq a) => Eq (Apply f a) where
Apply x == Apply y = eq1 x y
instance (Ord1 g, Ord a) => Ord (Apply g a) where
compare (Apply x) (Apply y) = compare1 x y
instance (Read1 f, Read a) => Read (Apply f a) where
readsPrec d s = [(Apply a, t) | (a, t) <- readsPrec1 d s]
instance (Show1 f, Show a) => Show (Apply f a) where
showsPrec p (Apply x) = showsPrec1 p x
makeFmapApplyNeg :: ClassRep a => a -> Name -> Type -> Name -> Q Exp
makeFmapApplyNeg = makeFmapApply False
makeFmapApplyPos :: ClassRep a => a -> Name -> Type -> Name -> Q Exp
makeFmapApplyPos = makeFmapApply True
makeFmapApply :: ClassRep a => Bool -> a -> Name -> Type -> Name -> Q Exp
makeFmapApply pos cRep conName (SigT ty _) name = makeFmapApply pos cRep conName ty name
makeFmapApply pos cRep conName t name = do
let tyCon :: Type
tyArgs :: [Type]
tyCon:tyArgs = unapplyTy t
numLastArgs :: Int
numLastArgs = min (arity cRep) (length tyArgs)
lhsArgs, rhsArgs :: [Type]
(lhsArgs, rhsArgs) = splitAt (length tyArgs - numLastArgs) tyArgs
inspectTy :: Type -> Q Exp
inspectTy (SigT ty _) = inspectTy ty
inspectTy (VarT a) | a == name = varE idValName
inspectTy beta = varE fmapValName `appE`
infixApp (if pos then makeFmapApply pos cRep conName beta name
else conE applyDataName)
(varE composeValName)
(if pos then varE unApplyValName
else makeFmapApply pos cRep conName beta name)
itf <- isTyFamily tyCon
if any (`mentionsName` [name]) lhsArgs
|| itf && any (`mentionsName` [name]) tyArgs
then outOfPlaceTyVarError cRep conName
else inspectTy (head rhsArgs)
applyDataName :: Name
applyDataName = mkNameG_d derivingCompatPackageKey "Data.Deriving.Internal" "Apply"
unApplyValName :: Name
unApplyValName = mkNameG_v derivingCompatPackageKey "Data.Deriving.Internal" "unApply"
# endif
#endif
#if MIN_VERSION_base(4,10,0)
showCommaSpaceValName :: Name
showCommaSpaceValName = mkNameG_v "base" "GHC.Show" "showCommaSpace"
#else
showCommaSpace :: ShowS
showCommaSpace = showString ", "
showCommaSpaceValName :: Name
showCommaSpaceValName = mkNameG_v derivingCompatPackageKey "Data.Deriving.Internal" "showCommaSpace"
#endif
#if MIN_VERSION_base(4,11,0)
appEndoValName :: Name
appEndoValName = mkNameG_v "base" "Data.Semigroup.Internal" "appEndo"
dualDataName :: Name
dualDataName = mkNameG_d "base" "Data.Semigroup.Internal" "Dual"
endoDataName :: Name
endoDataName = mkNameG_d "base" "Data.Semigroup.Internal" "Endo"
getDualValName :: Name
getDualValName = mkNameG_v "base" "Data.Semigroup.Internal" "getDual"
readFieldValName :: Name
readFieldValName = mkNameG_v "base" "GHC.Read" "readField"
readSymFieldValName :: Name
readSymFieldValName = mkNameG_v "base" "GHC.Read" "readSymField"
#else
appEndoValName :: Name
appEndoValName = mkNameG_v "base" "Data.Monoid" "appEndo"
dualDataName :: Name
dualDataName = mkNameG_d "base" "Data.Monoid" "Dual"
endoDataName :: Name
endoDataName = mkNameG_d "base" "Data.Monoid" "Endo"
getDualValName :: Name
getDualValName = mkNameG_v "base" "Data.Monoid" "getDual"
readField :: String -> ReadPrec a -> ReadPrec a
readField fieldName readVal = do
expectP (L.Ident fieldName)
expectP (L.Punc "=")
readVal
{-# NOINLINE readField #-}
readFieldValName :: Name
readFieldValName = mkNameG_v derivingCompatPackageKey "Data.Deriving.Internal" "readField"
readSymField :: String -> ReadPrec a -> ReadPrec a
readSymField fieldName readVal = do
expectP (L.Punc "(")
expectP (L.Symbol fieldName)
expectP (L.Punc ")")
expectP (L.Punc "=")
readVal
{-# NOINLINE readSymField #-}
readSymFieldValName :: Name
readSymFieldValName = mkNameG_v derivingCompatPackageKey "Data.Deriving.Internal" "readSymField"
#endif