module Data.Generics.Basics (
- -- Module Data.Typeable re-exported for convenience
+ -- * Module Data.Typeable re-exported for convenience
module Data.Typeable,
-- * The Data class for processing constructor applications
toConstr, -- :: a -> Constr
fromConstr, -- :: Constr -> a
dataTypeOf, -- :: a -> DataType
- cast0to1, -- mediate types and unary type constructors
- cast0to2 -- mediate types and binary type constructors
+ dataCast1, -- mediate types and unary type constructors
+ dataCast2 -- mediate types and binary type constructors
),
-- * Datatype representations
DataType, -- abstract, instance of: Show
Constr, -- abstract, instance of: Eq, Show
DataRep(..), -- instance of: Eq, Show
- ConRep(..), -- instance of: Eq, Show
+ ConstrRep(..), -- instance of: Eq, Show
ConIndex, -- alias for Int, start at 1
Fixity(..), -- instance of: Eq, Show
-- * Observers for datatype representations
- dataTypeCon, -- :: DataType -> String
+ dataTypeName, -- :: DataType -> String
dataTypeRep, -- :: DataType -> DataRep
- conDataType, -- :: Constr -> DataType
- conRep, -- :: Constr -> ConRep
- repCon, -- :: DataType -> ConRep -> Constr
+ constrType, -- :: Constr -> DataType
+ constrRep, -- :: Constr -> ConstrRep
+ repConstr, -- :: DataType -> ConstrRep -> Constr
-- * Representations of algebraic data types
- mkDataType, -- :: String -> [Constr] -> DataType
- mkDataCon, -- :: DataType -> String -> Fixity -> Constr
- algTypeCons, -- :: DataType -> [Constr]
- conFixity, -- :: Constr -> Fixity
+ mkDataType, -- :: String -> [Constr] -> DataType
+ mkConstr, -- :: DataType -> String -> Fixity -> Constr
+ dataTypeConstrs,-- :: DataType -> [Constr]
+ constrFields, -- :: Constr -> [String]
+ constrFixity, -- :: Constr -> Fixity
-- * From strings to constr's and vice versa: all data types
- conString, -- :: Constr -> String
- stringCon, -- :: DataType -> String -> Maybe Constr
+ showConstr, -- :: Constr -> String
+ readConstr, -- :: DataType -> String -> Maybe Constr
-- * Convenience funtions: algebraic data types
isAlgType, -- :: DataType -> Bool
- indexCon, -- :: DataType -> ConIndex -> Constr
- conIndex, -- :: Constr -> ConIndex
- maxConIndex, -- :: DataType -> ConIndex
+ indexConstr, -- :: DataType -> ConIndex -> Constr
+ constrIndex, -- :: Constr -> ConIndex
+ maxConstrIndex, -- :: DataType -> ConIndex
-- * Representation of primitive types
mkIntType, -- :: String -> DataType
mkFloatType, -- :: String -> DataType
mkStringType, -- :: String -> DataType
- mkIntCon, -- :: DataType -> Integer -> Constr
- mkFloatCon, -- :: DataType -> Double -> Constr
- mkStringCon, -- :: DataType -> String -> Constr
+ mkIntConstr, -- :: DataType -> Integer -> Constr
+ mkFloatConstr, -- :: DataType -> Double -> Constr
+ mkStringConstr, -- :: DataType -> String -> Constr
-- * Non-representations for non-presentable types
mkNorepType, -- :: String -> DataType
------------------------------------------------------------------------------
-- | Mediate types and unary type constructors
- cast0to1 :: Typeable1 t
- => (forall a. Data a => c (t a))
- -> Maybe (c a)
- cast0to1 _ = Nothing
+ dataCast1 :: Typeable1 t
+ => (forall a. Data a => c (t a))
+ -> Maybe (c a)
+ dataCast1 _ = Nothing
-- | Mediate types and binary type constructors
- cast0to2 :: Typeable2 t
- => (forall a b. (Data a, Data b) => c (t a b))
- -> Maybe (c a)
- cast0to2 _ = Nothing
+ dataCast2 :: Typeable2 t
+ => (forall a b. (Data a, Data b) => c (t a b))
+ -> Maybe (c a)
+ dataCast2 _ = Nothing
-- | Representation of constructors
data Constr = Constr
- { conrep :: ConRep
+ { conrep :: ConstrRep
, constring :: String
+ , confields :: [String] -- for AlgRep only
, confixity :: Fixity -- for AlgRep only
, datatype :: DataType
}
-- | Equality of constructors
instance Eq Constr where
- c == c' = conRep c == conRep c'
+ c == c' = constrRep c == constrRep c'
-- | Public representation of datatypes
-- | Public representation of constructors
-data ConRep = AlgCon ConIndex
- | IntCon Integer
- | FloatCon Double
- | StringCon String
+data ConstrRep = AlgConstr ConIndex
+ | IntConstr Integer
+ | FloatConstr Double
+ | StringConstr String
- deriving (Eq,Show)
+ deriving (Eq,Show)
--
-- | Gets the type constructor including the module
-dataTypeCon :: DataType -> String
-dataTypeCon = tycon
+dataTypeName :: DataType -> String
+dataTypeName = tycon
-- | Gets the datatype of a constructor
-conDataType :: Constr -> DataType
-conDataType = datatype
+constrType :: Constr -> DataType
+constrType = datatype
-- | Gets the public presentation of constructors
-conRep :: Constr -> ConRep
-conRep = conrep
+constrRep :: Constr -> ConstrRep
+constrRep = conrep
-- | Look up a constructor by its representation
-repCon :: DataType -> ConRep -> Constr
-repCon dt cr =
+repConstr :: DataType -> ConstrRep -> Constr
+repConstr dt cr =
case (dataTypeRep dt, cr) of
- (AlgRep cs, AlgCon i) -> cs !! (i-1)
- (IntRep, IntCon i) -> mkIntCon dt i
- (FloatRep, FloatCon f) -> mkFloatCon dt f
- (StringRep, StringCon str) -> mkStringCon dt str
- _ -> error "repCon"
+ (AlgRep cs, AlgConstr i) -> cs !! (i-1)
+ (IntRep, IntConstr i) -> mkIntConstr dt i
+ (FloatRep, FloatConstr f) -> mkFloatConstr dt f
+ (StringRep, StringConstr str) -> mkStringConstr dt str
+ _ -> error "repConstr"
-- | Constructs a constructor
-mkDataCon :: DataType -> String -> Fixity -> Constr
-mkDataCon dt str fix =
+mkConstr :: DataType -> String -> [String] -> Fixity -> Constr
+mkConstr dt str fields fix =
Constr
- { conrep = AlgCon idx
+ { conrep = AlgConstr idx
, constring = str
+ , confields = fields
, confixity = fix
, datatype = dt
}
where
- idx = head [ i | (c,i) <- algTypeCons dt `zip` [1..],
- conString c == str ]
+ idx = head [ i | (c,i) <- dataTypeConstrs dt `zip` [1..],
+ showConstr c == str ]
-- | Gets the constructors
-algTypeCons :: DataType -> [Constr]
-algTypeCons dt = case datarep dt of
- (AlgRep cons) -> cons
- _ -> error "algTypeCons"
+dataTypeConstrs :: DataType -> [Constr]
+dataTypeConstrs dt = case datarep dt of
+ (AlgRep cons) -> cons
+ _ -> error "dataTypeConstrs"
+
+
+-- | Gets the field labels of a constructor
+constrFields :: Constr -> [String]
+constrFields = confields
-- | Gets the fixity of a constructor
-conFixity :: Constr -> Fixity
-conFixity = confixity
+constrFixity :: Constr -> Fixity
+constrFixity = confixity
-- | Gets the string for a constructor
-conString :: Constr -> String
-conString = constring
+showConstr :: Constr -> String
+showConstr = constring
-- | Lookup a constructor via a string
-stringCon :: DataType -> String -> Maybe Constr
-stringCon dt str =
+readConstr :: DataType -> String -> Maybe Constr
+readConstr dt str =
case dataTypeRep dt of
AlgRep cons -> idx cons
- IntRep -> mkReadCon (\i -> (mkPrimCon dt str (IntCon i)))
- FloatRep -> mkReadCon (\f -> (mkPrimCon dt str (FloatCon f)))
- StringRep -> Just (mkStringCon dt str)
+ IntRep -> mkReadCon (\i -> (mkPrimCon dt str (IntConstr i)))
+ FloatRep -> mkReadCon (\f -> (mkPrimCon dt str (FloatConstr f)))
+ StringRep -> Just (mkStringConstr dt str)
NoRep -> Nothing
where
-- Traverse list of algebraic datatype constructors
idx :: [Constr] -> Maybe Constr
- idx cons = let fit = filter ((==) str . conString) cons
+ idx cons = let fit = filter ((==) str . showConstr) cons
in if fit == []
then Nothing
else Just (head fit)
-- | Gets the constructor for an index
-indexCon :: DataType -> ConIndex -> Constr
-indexCon dt idx = case datarep dt of
- (AlgRep cs) -> cs !! (idx-1)
- _ -> error "indexCon"
+indexConstr :: DataType -> ConIndex -> Constr
+indexConstr dt idx = case datarep dt of
+ (AlgRep cs) -> cs !! (idx-1)
+ _ -> error "indexConstr"
-- | Gets the index of a constructor
-conIndex :: Constr -> ConIndex
-conIndex con = case conRep con of
- (AlgCon idx) -> idx
- _ -> error "conIndex"
+constrIndex :: Constr -> ConIndex
+constrIndex con = case constrRep con of
+ (AlgConstr idx) -> idx
+ _ -> error "constrIndex"
-- | Gets the maximum constructor index
-maxConIndex :: DataType -> ConIndex
-maxConIndex dt = case dataTypeRep dt of
- AlgRep cs -> length cs
- _ -> error "maxConIndex"
+maxConstrIndex :: DataType -> ConIndex
+maxConstrIndex dt = case dataTypeRep dt of
+ AlgRep cs -> length cs
+ _ -> error "maxConstrIndex"
-- Makes a constructor for primitive types
-mkPrimCon :: DataType -> String -> ConRep -> Constr
+mkPrimCon :: DataType -> String -> ConstrRep -> Constr
mkPrimCon dt str cr = Constr
{ datatype = dt
, conrep = cr
, constring = str
- , confixity = error "conFixity"
+ , confields = error "constrFields"
+ , confixity = error "constrFixity"
}
-mkIntCon :: DataType -> Integer -> Constr
-mkIntCon dt i = case datarep dt of
- IntRep -> mkPrimCon dt (show i) (IntCon i)
- _ -> error "mkIntCon"
+mkIntConstr :: DataType -> Integer -> Constr
+mkIntConstr dt i = case datarep dt of
+ IntRep -> mkPrimCon dt (show i) (IntConstr i)
+ _ -> error "mkIntConstr"
-mkFloatCon :: DataType -> Double -> Constr
-mkFloatCon dt f = case datarep dt of
- FloatRep -> mkPrimCon dt (show f) (FloatCon f)
- _ -> error "mkFloatCon"
+mkFloatConstr :: DataType -> Double -> Constr
+mkFloatConstr dt f = case datarep dt of
+ FloatRep -> mkPrimCon dt (show f) (FloatConstr f)
+ _ -> error "mkFloatConstr"
-mkStringCon :: DataType -> String -> Constr
-mkStringCon dt str = case datarep dt of
- StringRep -> mkPrimCon dt str (StringCon str)
- _ -> error "mkStringCon"
+mkStringConstr :: DataType -> String -> Constr
+mkStringConstr dt str = case datarep dt of
+ StringRep -> mkPrimCon dt str (StringConstr str)
+ _ -> error "mkStringConstr"
------------------------------------------------------------------------------
projects / ghc-base.git / blobdiff