Safe Haskell	None
Language	Haskell2010

Data.SCargot.Repr

Contents

Rich SExpr representation
Well-Formed SExpr representation

Synopsis

Documentation

This module contains several different representations for s-expressions. The s-cargot library underlying uses the SExpr type as its representation type, which is a binary tree representation with an arbitrary type for its leaves.

This type is not always convenient to manipulate in Haskell code, this module defines two alternate representations which turn a sequence of nested right-branching cons pairs into Haskell lists: that is to say, they transform between

SCons a (SCons b (SCons c SNil))  <=>  RSList [a, b, c]

These two types differ in how they handle non-well-formed lists, i.e. lists that end with an atom. The RichSExpr format handles this with a special constructor for lists that end in an atom:

SCons a (SCons b (SAtom c))  <=>  RSDotted [a, b] c

On the other hand, the WellFormedSExpr type elects not to handle this case. This is unusual for Lisp source code, but is a reasonable choice for configuration or data storage formats that use s-expressions, where non-well-formed lists would be an unnecessary complication.

To make working with these types less verbose, there are other modules that export pattern aliases and helper functions: these can be found at Data.SCargot.Repr.Basic, Data.SCargot.Repr.Rich, and Data.SCargot.Repr.WellFormed.

data SExpr atom Source #

All S-Expressions can be understood as a sequence of cons cells (represented here by SCons), the empty list nil (represented by SNil) or an atom.

Constructors

SCons (SExpr atom) (SExpr atom)
SAtom atom
SNil

Instances

Functor SExpr Source #
Methods fmap :: (a -> b) -> SExpr a -> SExpr b # (<$) :: a -> SExpr b -> SExpr a #
Foldable SExpr Source #
Methods fold :: Monoid m => SExpr m -> m # foldMap :: Monoid m => (a -> m) -> SExpr a -> m # foldr :: (a -> b -> b) -> b -> SExpr a -> b # foldr' :: (a -> b -> b) -> b -> SExpr a -> b # foldl :: (b -> a -> b) -> b -> SExpr a -> b # foldl' :: (b -> a -> b) -> b -> SExpr a -> b # foldr1 :: (a -> a -> a) -> SExpr a -> a # foldl1 :: (a -> a -> a) -> SExpr a -> a # toList :: SExpr a -> [a] # null :: SExpr a -> Bool # length :: SExpr a -> Int # elem :: Eq a => a -> SExpr a -> Bool # maximum :: Ord a => SExpr a -> a # minimum :: Ord a => SExpr a -> a # sum :: Num a => SExpr a -> a # product :: Num a => SExpr a -> a #
Traversable SExpr Source #
Methods traverse :: Applicative f => (a -> f b) -> SExpr a -> f (SExpr b) # sequenceA :: Applicative f => SExpr (f a) -> f (SExpr a) # mapM :: Monad m => (a -> m b) -> SExpr a -> m (SExpr b) # sequence :: Monad m => SExpr (m a) -> m (SExpr a) #
IsList (SExpr atom) Source #
Associated Types type Item (SExpr atom) :: * # Methods fromList :: [Item (SExpr atom)] -> SExpr atom # fromListN :: Int -> [Item (SExpr atom)] -> SExpr atom # toList :: SExpr atom -> [Item (SExpr atom)] #
Eq atom => Eq (SExpr atom) Source #
Methods (==) :: SExpr atom -> SExpr atom -> Bool # (/=) :: SExpr atom -> SExpr atom -> Bool #
Data atom => Data (SExpr atom) Source #
Methods gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> SExpr atom -> c (SExpr atom) # gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (SExpr atom) # toConstr :: SExpr atom -> Constr # dataTypeOf :: SExpr atom -> DataType # dataCast1 :: Typeable (* -> ) t => (forall d. Data d => c (t d)) -> Maybe (c (SExpr atom)) # dataCast2 :: Typeable ( -> * -> *) t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (SExpr atom)) # gmapT :: (forall b. Data b => b -> b) -> SExpr atom -> SExpr atom # gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> SExpr atom -> r # gmapQr :: (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> SExpr atom -> r # gmapQ :: (forall d. Data d => d -> u) -> SExpr atom -> [u] # gmapQi :: Int -> (forall d. Data d => d -> u) -> SExpr atom -> u # gmapM :: Monad m => (forall d. Data d => d -> m d) -> SExpr atom -> m (SExpr atom) # gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> SExpr atom -> m (SExpr atom) # gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> SExpr atom -> m (SExpr atom) #
Read atom => Read (SExpr atom) Source #
Methods readsPrec :: Int -> ReadS (SExpr atom) # readList :: ReadS [SExpr atom] # readPrec :: ReadPrec (SExpr atom) # readListPrec :: ReadPrec [SExpr atom] #
Show atom => Show (SExpr atom) Source #
Methods showsPrec :: Int -> SExpr atom -> ShowS # show :: SExpr atom -> String # showList :: [SExpr atom] -> ShowS #
IsString atom => IsString (SExpr atom) Source #
Methods fromString :: String -> SExpr atom #
type Item (SExpr atom) Source #
type Item (SExpr atom) = SExpr atom

Rich SExpr representation

data RichSExpr atom Source #

Sometimes the cons-based interface is too low level, and we'd rather have the lists themselves exposed. In this case, we have RSList to represent a well-formed cons list, and RSDotted to represent an improper list of the form (a b c . d). This representation is based on the structure of the parsed S-Expression, and not on how it was originally represented: thus, (a . (b)) is going to be represented as RSList[RSAtom a, RSAtom b] despite having been originally represented as a dotted list.

Constructors

RSList [RichSExpr atom]
RSDotted [RichSExpr atom] atom
RSAtom atom

Instances

Functor RichSExpr Source #
Methods fmap :: (a -> b) -> RichSExpr a -> RichSExpr b # (<$) :: a -> RichSExpr b -> RichSExpr a #
Foldable RichSExpr Source #
Methods fold :: Monoid m => RichSExpr m -> m # foldMap :: Monoid m => (a -> m) -> RichSExpr a -> m # foldr :: (a -> b -> b) -> b -> RichSExpr a -> b # foldr' :: (a -> b -> b) -> b -> RichSExpr a -> b # foldl :: (b -> a -> b) -> b -> RichSExpr a -> b # foldl' :: (b -> a -> b) -> b -> RichSExpr a -> b # foldr1 :: (a -> a -> a) -> RichSExpr a -> a # foldl1 :: (a -> a -> a) -> RichSExpr a -> a # toList :: RichSExpr a -> [a] # null :: RichSExpr a -> Bool # length :: RichSExpr a -> Int # elem :: Eq a => a -> RichSExpr a -> Bool # maximum :: Ord a => RichSExpr a -> a # minimum :: Ord a => RichSExpr a -> a # sum :: Num a => RichSExpr a -> a # product :: Num a => RichSExpr a -> a #
Traversable RichSExpr Source #
Methods traverse :: Applicative f => (a -> f b) -> RichSExpr a -> f (RichSExpr b) # sequenceA :: Applicative f => RichSExpr (f a) -> f (RichSExpr a) # mapM :: Monad m => (a -> m b) -> RichSExpr a -> m (RichSExpr b) # sequence :: Monad m => RichSExpr (m a) -> m (RichSExpr a) #
IsList (RichSExpr atom) Source #
Associated Types type Item (RichSExpr atom) :: * # Methods fromList :: [Item (RichSExpr atom)] -> RichSExpr atom # fromListN :: Int -> [Item (RichSExpr atom)] -> RichSExpr atom # toList :: RichSExpr atom -> [Item (RichSExpr atom)] #
Eq atom => Eq (RichSExpr atom) Source #
Methods (==) :: RichSExpr atom -> RichSExpr atom -> Bool # (/=) :: RichSExpr atom -> RichSExpr atom -> Bool #
Data atom => Data (RichSExpr atom) Source #
Methods gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> RichSExpr atom -> c (RichSExpr atom) # gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (RichSExpr atom) # toConstr :: RichSExpr atom -> Constr # dataTypeOf :: RichSExpr atom -> DataType # dataCast1 :: Typeable (* -> ) t => (forall d. Data d => c (t d)) -> Maybe (c (RichSExpr atom)) # dataCast2 :: Typeable ( -> * -> *) t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (RichSExpr atom)) # gmapT :: (forall b. Data b => b -> b) -> RichSExpr atom -> RichSExpr atom # gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> RichSExpr atom -> r # gmapQr :: (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> RichSExpr atom -> r # gmapQ :: (forall d. Data d => d -> u) -> RichSExpr atom -> [u] # gmapQi :: Int -> (forall d. Data d => d -> u) -> RichSExpr atom -> u # gmapM :: Monad m => (forall d. Data d => d -> m d) -> RichSExpr atom -> m (RichSExpr atom) # gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> RichSExpr atom -> m (RichSExpr atom) # gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> RichSExpr atom -> m (RichSExpr atom) #
Read atom => Read (RichSExpr atom) Source #
Methods readsPrec :: Int -> ReadS (RichSExpr atom) # readList :: ReadS [RichSExpr atom] # readPrec :: ReadPrec (RichSExpr atom) # readListPrec :: ReadPrec [RichSExpr atom] #
Show atom => Show (RichSExpr atom) Source #
Methods showsPrec :: Int -> RichSExpr atom -> ShowS # show :: RichSExpr atom -> String # showList :: [RichSExpr atom] -> ShowS #
IsString atom => IsString (RichSExpr atom) Source #
Methods fromString :: String -> RichSExpr atom #
type Item (RichSExpr atom) Source #
type Item (RichSExpr atom) = RichSExpr atom

toRich :: SExpr atom -> RichSExpr atom Source #

It should always be true that

fromRich (toRich x) == x

and that

toRich (fromRich x) == x

fromRich :: RichSExpr atom -> SExpr atom Source #

This follows the same laws as toRich.

Well-Formed SExpr representation

data WellFormedSExpr atom Source #

A well-formed s-expression is one which does not contain any dotted lists. This means that not every value of SExpr a can be converted to a WellFormedSExpr a, although the opposite is fine.

Constructors

WFSList [WellFormedSExpr atom]
WFSAtom atom

Instances

Functor WellFormedSExpr Source #
Methods fmap :: (a -> b) -> WellFormedSExpr a -> WellFormedSExpr b # (<$) :: a -> WellFormedSExpr b -> WellFormedSExpr a #
Foldable WellFormedSExpr Source #
Methods fold :: Monoid m => WellFormedSExpr m -> m # foldMap :: Monoid m => (a -> m) -> WellFormedSExpr a -> m # foldr :: (a -> b -> b) -> b -> WellFormedSExpr a -> b # foldr' :: (a -> b -> b) -> b -> WellFormedSExpr a -> b # foldl :: (b -> a -> b) -> b -> WellFormedSExpr a -> b # foldl' :: (b -> a -> b) -> b -> WellFormedSExpr a -> b # foldr1 :: (a -> a -> a) -> WellFormedSExpr a -> a # foldl1 :: (a -> a -> a) -> WellFormedSExpr a -> a # toList :: WellFormedSExpr a -> [a] # null :: WellFormedSExpr a -> Bool # length :: WellFormedSExpr a -> Int # elem :: Eq a => a -> WellFormedSExpr a -> Bool # maximum :: Ord a => WellFormedSExpr a -> a # minimum :: Ord a => WellFormedSExpr a -> a # sum :: Num a => WellFormedSExpr a -> a # product :: Num a => WellFormedSExpr a -> a #
Traversable WellFormedSExpr Source #
Methods traverse :: Applicative f => (a -> f b) -> WellFormedSExpr a -> f (WellFormedSExpr b) # sequenceA :: Applicative f => WellFormedSExpr (f a) -> f (WellFormedSExpr a) # mapM :: Monad m => (a -> m b) -> WellFormedSExpr a -> m (WellFormedSExpr b) # sequence :: Monad m => WellFormedSExpr (m a) -> m (WellFormedSExpr a) #
IsList (WellFormedSExpr atom) Source #
Associated Types type Item (WellFormedSExpr atom) :: * # Methods fromList :: [Item (WellFormedSExpr atom)] -> WellFormedSExpr atom # fromListN :: Int -> [Item (WellFormedSExpr atom)] -> WellFormedSExpr atom # toList :: WellFormedSExpr atom -> [Item (WellFormedSExpr atom)] #
Eq atom => Eq (WellFormedSExpr atom) Source #
Methods (==) :: WellFormedSExpr atom -> WellFormedSExpr atom -> Bool # (/=) :: WellFormedSExpr atom -> WellFormedSExpr atom -> Bool #
Data atom => Data (WellFormedSExpr atom) Source #
Methods gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> WellFormedSExpr atom -> c (WellFormedSExpr atom) # gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (WellFormedSExpr atom) # toConstr :: WellFormedSExpr atom -> Constr # dataTypeOf :: WellFormedSExpr atom -> DataType # dataCast1 :: Typeable (* -> ) t => (forall d. Data d => c (t d)) -> Maybe (c (WellFormedSExpr atom)) # dataCast2 :: Typeable ( -> * -> *) t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (WellFormedSExpr atom)) # gmapT :: (forall b. Data b => b -> b) -> WellFormedSExpr atom -> WellFormedSExpr atom # gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> WellFormedSExpr atom -> r # gmapQr :: (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> WellFormedSExpr atom -> r # gmapQ :: (forall d. Data d => d -> u) -> WellFormedSExpr atom -> [u] # gmapQi :: Int -> (forall d. Data d => d -> u) -> WellFormedSExpr atom -> u # gmapM :: Monad m => (forall d. Data d => d -> m d) -> WellFormedSExpr atom -> m (WellFormedSExpr atom) # gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> WellFormedSExpr atom -> m (WellFormedSExpr atom) # gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> WellFormedSExpr atom -> m (WellFormedSExpr atom) #
Read atom => Read (WellFormedSExpr atom) Source #
Methods readsPrec :: Int -> ReadS (WellFormedSExpr atom) # readList :: ReadS [WellFormedSExpr atom] # readPrec :: ReadPrec (WellFormedSExpr atom) # readListPrec :: ReadPrec [WellFormedSExpr atom] #
Show atom => Show (WellFormedSExpr atom) Source #
Methods showsPrec :: Int -> WellFormedSExpr atom -> ShowS # show :: WellFormedSExpr atom -> String # showList :: [WellFormedSExpr atom] -> ShowS #
IsString atom => IsString (WellFormedSExpr atom) Source #
Methods fromString :: String -> WellFormedSExpr atom #
type Item (WellFormedSExpr atom) Source #
type Item (WellFormedSExpr atom) = WellFormedSExpr atom

toWellFormed :: SExpr atom -> Either String (WellFormedSExpr atom) Source #

This will be Nothing if the argument contains an improper list. It should hold that

toWellFormed (fromWellFormed x) == Right x

and also (more tediously) that

case toWellFormed x of
  Left _  -> True
  Right y -> x == fromWellFormed y

fromWellFormed :: WellFormedSExpr atom -> SExpr atom Source #

Convert a WellFormedSExpr back into a SExpr.