Copyright	(c) Sjoerd Visscher 2020
Maintainer	sjoerd@w3future.com
Stability	experimental
Portability	non-portable
Safe Haskell	None
Language	Haskell2010

Data.DeriveLiftedInstances.Internal

Contents

Orphan instances

Description

Synopsis

data Derivator = Derivator {
- res :: Q Exp -> Q Exp
- op :: Name -> Q Exp -> Q Exp
- arg :: Type -> Q Exp -> Q Exp
- var :: (Q Exp -> Q Exp -> Q Exp) -> Q Exp -> Q Exp
- ap :: Q Exp -> Q Exp -> Q Exp
}
varExp :: Name -> Q Exp
varPat :: Name -> Q Pat
idDeriv :: Derivator
deriveInstance :: Derivator -> Q Type -> Q [Dec]
deriveInstance' :: Derivator -> Cxt -> Name -> Type -> Q [Dec]
buildOperation :: Derivator -> Name -> Type -> Q Exp -> Q ([Name], Exp)
buildArgument :: Name -> Type -> Q Exp -> Q Exp -> Q Exp
isVar :: Name -> Type -> Bool
hasVar :: Name -> Type -> Bool
tvName :: TyVarBndr -> Name
contains :: Data d => Name -> d -> Bool
data ShowsPrec
- = ShowsPrec (Int -> String -> String)
- | ShowOp2 Fixity (Int -> String -> String)
- | ShowOp1 Fixity (Int -> String -> String)
showAp :: ShowsPrec -> ShowsPrec -> ShowsPrec
showDeriv :: Derivator
isOperator :: String -> Bool

Documentation

data Derivator Source #

To write your own Derivator you need to show how each part of a method gets lifted. For example, when deriving an instance for type a of the following methods:

meth0 :: a
meth1 :: Int -> a
meth2 :: a -> Either Bool a -> Int
meth3 :: Maybe [a] -> a

the resulting template haskell declarations are (pseudo code):

meth0 = $res ($op "meth0" meth0)
meth1 a = $res (($op "meth1" meth1) `$ap` ($arg Int a))
meth2 v0 v1 = (($op "meth2" meth2) `$ap` ($var fold0 v0)) `$ap` ($var fold1 v1)
  where
    fold0 _ f = f
    fold1 map f = [| $map $f |]
meth3 v2 = $res (($op "meth2" meth2) `$ap` ($var fold2 v2))
  where
    fold2 map f = [| $map ($map $f) |]

Constructors

Derivator
Fields res :: Q Exp -> Q Exp Convert the result of the method op :: Name -> Q Exp -> Q Exp Convert the method (still unapplied to any arguments) arg :: Type -> Q Exp -> Q Exp Convert an argument var :: (Q Exp -> Q Exp -> Q Exp) -> Q Exp -> Q Exp Convert a variable ap :: Q Exp -> Q Exp -> Q Exp Apply an argument or variable to the method

varExp :: Name -> Q Exp Source #

varPat :: Name -> Q Pat Source #

idDeriv :: Derivator Source #

The identity Derivator. Not useful on its own, but often used as input for other Derivators.

deriveInstance :: Derivator -> Q Type -> Q [Dec] Source #

Derive the instance with the given Derivator and the given instance head.

The instance head can be passed as a template haskell type quotation, for example:

{-# LANGUAGE TemplateHaskell #-}
[t| Num ShowsPrec |]
[t| forall a. Num a => Num [a] |]
[t| forall a b. (Num a, Num b) => Num (a, b) |]

deriveInstance' :: Derivator -> Cxt -> Name -> Type -> Q [Dec] Source #

buildOperation :: Derivator -> Name -> Type -> Q Exp -> Q ([Name], Exp) Source #

buildArgument :: Name -> Type -> Q Exp -> Q Exp -> Q Exp Source #

isVar :: Name -> Type -> Bool Source #

hasVar :: Name -> Type -> Bool Source #

tvName :: TyVarBndr -> Name Source #

contains :: Data d => Name -> d -> Bool Source #

data ShowsPrec Source #

Helper for showing infix expressions

Constructors

ShowsPrec (Int -> String -> String)
ShowOp2 Fixity (Int -> String -> String)
ShowOp1 Fixity (Int -> String -> String)

Instances

Instances details

Bounded ShowsPrec Source #
Instance details Defined in Data.DeriveLiftedInstances Methods minBound :: ShowsPrec # maxBound :: ShowsPrec #
Floating ShowsPrec Source #
Instance details Defined in Data.DeriveLiftedInstances Methods pi :: ShowsPrec # exp :: ShowsPrec -> ShowsPrec # log :: ShowsPrec -> ShowsPrec # sqrt :: ShowsPrec -> ShowsPrec # (**) :: ShowsPrec -> ShowsPrec -> ShowsPrec # logBase :: ShowsPrec -> ShowsPrec -> ShowsPrec # sin :: ShowsPrec -> ShowsPrec # cos :: ShowsPrec -> ShowsPrec # tan :: ShowsPrec -> ShowsPrec # asin :: ShowsPrec -> ShowsPrec # acos :: ShowsPrec -> ShowsPrec # atan :: ShowsPrec -> ShowsPrec # sinh :: ShowsPrec -> ShowsPrec # cosh :: ShowsPrec -> ShowsPrec # tanh :: ShowsPrec -> ShowsPrec # asinh :: ShowsPrec -> ShowsPrec # acosh :: ShowsPrec -> ShowsPrec # atanh :: ShowsPrec -> ShowsPrec # log1p :: ShowsPrec -> ShowsPrec # expm1 :: ShowsPrec -> ShowsPrec # log1pexp :: ShowsPrec -> ShowsPrec # log1mexp :: ShowsPrec -> ShowsPrec #
Fractional ShowsPrec Source #
Instance details Defined in Data.DeriveLiftedInstances Methods (/) :: ShowsPrec -> ShowsPrec -> ShowsPrec # recip :: ShowsPrec -> ShowsPrec # fromRational :: Rational -> ShowsPrec #
Num ShowsPrec Source #
Instance details Defined in Data.DeriveLiftedInstances Methods (+) :: ShowsPrec -> ShowsPrec -> ShowsPrec # (-) :: ShowsPrec -> ShowsPrec -> ShowsPrec # (*) :: ShowsPrec -> ShowsPrec -> ShowsPrec # negate :: ShowsPrec -> ShowsPrec # abs :: ShowsPrec -> ShowsPrec # signum :: ShowsPrec -> ShowsPrec # fromInteger :: Integer -> ShowsPrec #
Show ShowsPrec Source #
Instance details Defined in Data.DeriveLiftedInstances.Internal Methods showsPrec :: Int -> ShowsPrec -> ShowS # show :: ShowsPrec -> String # showList :: [ShowsPrec] -> ShowS #
Semigroup ShowsPrec Source #
Instance details Defined in Data.DeriveLiftedInstances Methods (<>) :: ShowsPrec -> ShowsPrec -> ShowsPrec # sconcat :: NonEmpty ShowsPrec -> ShowsPrec # stimes :: Integral b => b -> ShowsPrec -> ShowsPrec #
Monoid ShowsPrec Source #
Instance details Defined in Data.DeriveLiftedInstances Methods mempty :: ShowsPrec # mappend :: ShowsPrec -> ShowsPrec -> ShowsPrec # mconcat :: [ShowsPrec] -> ShowsPrec #

showAp :: ShowsPrec -> ShowsPrec -> ShowsPrec Source #

showDeriv :: Derivator Source #

Derive instances for ShowsPrec. Example:

deriveInstance showDeriv [t| Num ShowsPrec |]

> show ((6 * 7) ^ 2 :: ShowsPrec)
"fromInteger 6 * fromInteger 7 * (fromInteger 6 * fromInteger 7)"

isOperator :: String -> Bool Source #

Orphan instances

Lift Fixity Source #
Instance details Methods lift :: Fixity -> Q Exp # liftTyped :: Fixity -> Q (TExp Fixity) #
Lift FixityDirection Source #
Instance details Methods lift :: FixityDirection -> Q Exp # liftTyped :: FixityDirection -> Q (TExp FixityDirection) #