module Language.PureScript.Pretty.Types (
prettyPrintType,
prettyPrintTypeAtom,
prettyPrintRow
) where
import Data.Maybe (fromMaybe)
import Data.List (intercalate)
import Control.Arrow ((<+>))
import Control.PatternArrows
import Language.PureScript.Types
import Language.PureScript.Kinds
import Language.PureScript.Pretty.Common
import Language.PureScript.Pretty.Kinds
import Language.PureScript.Environment
typeLiterals :: Pattern () Type String
typeLiterals = mkPattern match
where
match TypeWildcard = Just "_"
match (TypeVar var) = Just var
match (PrettyPrintObject row) = Just $ "{ " ++ prettyPrintRow row ++ " }"
match (TypeConstructor ctor) = Just $ show ctor
match (TUnknown u) = Just $ '_' : show u
match (Skolem name s _) = Just $ name ++ show s
match (ConstrainedType deps ty) = Just $ "(" ++ intercalate ", " (map (\(pn, ty') -> show pn ++ " " ++ unwords (map prettyPrintTypeAtom ty')) deps) ++ ") => " ++ prettyPrintType ty
match (SaturatedTypeSynonym name args) = Just $ show name ++ "<" ++ intercalate "," (map prettyPrintTypeAtom args) ++ ">"
match REmpty = Just "()"
match row@RCons{} = Just $ '(' : prettyPrintRow row ++ ")"
match _ = Nothing
prettyPrintRow :: Type -> String
prettyPrintRow = (\(tys, rest) -> intercalate ", " (map (uncurry nameAndTypeToPs) tys) ++ tailToPs rest) . toList []
where
nameAndTypeToPs :: String -> Type -> String
nameAndTypeToPs name ty = prettyPrintObjectKey name ++ " :: " ++ prettyPrintType ty
tailToPs :: Type -> String
tailToPs REmpty = ""
tailToPs other = " | " ++ prettyPrintType other
toList :: [(String, Type)] -> Type -> ([(String, Type)], Type)
toList tys (RCons name ty row) = toList ((name, ty):tys) row
toList tys r = (tys, r)
typeApp :: Pattern () Type (Type, Type)
typeApp = mkPattern match
where
match (TypeApp f x) = Just (f, x)
match _ = Nothing
appliedFunction :: Pattern () Type (Type, Type)
appliedFunction = mkPattern match
where
match (PrettyPrintFunction arg ret) = Just (arg, ret)
match _ = Nothing
kinded :: Pattern () Type (Kind, Type)
kinded = mkPattern match
where
match (KindedType t k) = Just (k, t)
match _ = Nothing
insertPlaceholders :: Type -> Type
insertPlaceholders = everywhereOnTypesTopDown convertForAlls . everywhereOnTypes convert
where
convert (TypeApp (TypeApp f arg) ret) | f == tyFunction = PrettyPrintFunction arg ret
convert (TypeApp o r) | o == tyObject = PrettyPrintObject r
convert other = other
convertForAlls (ForAll ident ty _) = go [ident] ty
where
go idents (ForAll ident' ty' _) = go (ident' : idents) ty'
go idents other = PrettyPrintForAll idents other
convertForAlls other = other
matchTypeAtom :: Pattern () Type String
matchTypeAtom = typeLiterals <+> fmap parens matchType
matchType :: Pattern () Type String
matchType = buildPrettyPrinter operators matchTypeAtom
where
operators :: OperatorTable () Type String
operators =
OperatorTable [ [ AssocL typeApp $ \f x -> f ++ " " ++ x ]
, [ AssocR appliedFunction $ \arg ret -> arg ++ " -> " ++ ret
]
, [ Wrap forall_ $ \idents ty -> "forall " ++ unwords idents ++ ". " ++ ty ]
, [ Wrap kinded $ \k ty -> ty ++ " :: " ++ prettyPrintKind k ]
]
forall_ :: Pattern () Type ([String], Type)
forall_ = mkPattern match
where
match (PrettyPrintForAll idents ty) = Just (idents, ty)
match _ = Nothing
prettyPrintTypeAtom :: Type -> String
prettyPrintTypeAtom = fromMaybe (error "Incomplete pattern") . pattern matchTypeAtom () . insertPlaceholders
prettyPrintType :: Type -> String
prettyPrintType = fromMaybe (error "Incomplete pattern") . pattern matchType () . insertPlaceholders