Data.Tagged

Tagged values

newtype Tagged s b

A Tagged s b value is a value b with an attached phantom type s. This can be used in place of the more traditional but less safe idiom of passing in an undefined value with the type, because unlike an (s -> b), a Tagged s b can't try to use the argument s as a real value.

Moreover, you don't have to rely on the compiler to inline away the extra argument, because the newtype is "free"

Tagged has kind k -> * -> * if the compiler supports PolyKinds, therefore there is an extra k showing in the instance haddocks that may cause confusion.

Constructors

Tagged

Fields

• unTagged :: b

Instances

Bifunctor (Tagged *)

Methods

bimap :: (a -> b) -> (c -> d) -> Tagged * a c -> Tagged * b d

first :: (a -> b) -> Tagged * a c -> Tagged * b c

second :: (b -> c) -> Tagged * a b -> Tagged * a c

Monad (Tagged k s)

Methods

(>>=) :: Tagged k s a -> (a -> Tagged k s b) -> Tagged k s b

(>>) :: Tagged k s a -> Tagged k s b -> Tagged k s b

return :: a -> Tagged k s a

fail :: String -> Tagged k s a

Functor (Tagged k s)

Methods

fmap :: (a -> b) -> Tagged k s a -> Tagged k s b

(<$) :: a -> Tagged k s b -> Tagged k s a

Applicative (Tagged k s)

Methods

pure :: a -> Tagged k s a

(<*>) :: Tagged k s (a -> b) -> Tagged k s a -> Tagged k s b

(*>) :: Tagged k s a -> Tagged k s b -> Tagged k s b

(<*) :: Tagged k s a -> Tagged k s b -> Tagged k s a

Foldable (Tagged k s)

Methods

fold :: Monoid m => Tagged k s m -> m

foldMap :: Monoid m => (a -> m) -> Tagged k s a -> m

foldr :: (a -> b -> b) -> b -> Tagged k s a -> b

foldr' :: (a -> b -> b) -> b -> Tagged k s a -> b

foldl :: (b -> a -> b) -> b -> Tagged k s a -> b

foldl' :: (b -> a -> b) -> b -> Tagged k s a -> b

foldr1 :: (a -> a -> a) -> Tagged k s a -> a

foldl1 :: (a -> a -> a) -> Tagged k s a -> a

toList :: Tagged k s a -> [a]

null :: Tagged k s a -> Bool

length :: Tagged k s a -> Int

elem :: Eq a => a -> Tagged k s a -> Bool

maximum :: Ord a => Tagged k s a -> a

minimum :: Ord a => Tagged k s a -> a

sum :: Num a => Tagged k s a -> a

product :: Num a => Tagged k s a -> a

Traversable (Tagged k s)

Methods

traverse :: Applicative f => (a -> f b) -> Tagged k s a -> f (Tagged k s b)

sequenceA :: Applicative f => Tagged k s (f a) -> f (Tagged k s a)

mapM :: Monad m => (a -> m b) -> Tagged k s a -> m (Tagged k s b)

sequence :: Monad m => Tagged k s (m a) -> m (Tagged k s a)

Generic1 (Tagged k s)

Associated Types

type Rep1 (Tagged k s :: * -> *) :: * -> *

Methods

from1 :: Tagged k s a -> Rep1 (Tagged k s) a

to1 :: Rep1 (Tagged k s) a -> Tagged k s a

Bounded b => Bounded (Tagged k s b)

Methods

minBound :: Tagged k s b

maxBound :: Tagged k s b

Enum a => Enum (Tagged k s a)

Methods

succ :: Tagged k s a -> Tagged k s a

pred :: Tagged k s a -> Tagged k s a

toEnum :: Int -> Tagged k s a

fromEnum :: Tagged k s a -> Int

enumFrom :: Tagged k s a -> [Tagged k s a]

enumFromThen :: Tagged k s a -> Tagged k s a -> [Tagged k s a]

enumFromTo :: Tagged k s a -> Tagged k s a -> [Tagged k s a]

enumFromThenTo :: Tagged k s a -> Tagged k s a -> Tagged k s a -> [Tagged k s a]

Eq b => Eq (Tagged k s b)

Methods

(==) :: Tagged k s b -> Tagged k s b -> Bool

(/=) :: Tagged k s b -> Tagged k s b -> Bool

Floating a => Floating (Tagged k s a)

Methods

pi :: Tagged k s a

exp :: Tagged k s a -> Tagged k s a

log :: Tagged k s a -> Tagged k s a

sqrt :: Tagged k s a -> Tagged k s a

(**) :: Tagged k s a -> Tagged k s a -> Tagged k s a

logBase :: Tagged k s a -> Tagged k s a -> Tagged k s a

sin :: Tagged k s a -> Tagged k s a

cos :: Tagged k s a -> Tagged k s a

tan :: Tagged k s a -> Tagged k s a

asin :: Tagged k s a -> Tagged k s a

acos :: Tagged k s a -> Tagged k s a

atan :: Tagged k s a -> Tagged k s a

sinh :: Tagged k s a -> Tagged k s a

cosh :: Tagged k s a -> Tagged k s a

tanh :: Tagged k s a -> Tagged k s a

asinh :: Tagged k s a -> Tagged k s a

acosh :: Tagged k s a -> Tagged k s a

atanh :: Tagged k s a -> Tagged k s a

log1p :: Tagged k s a -> Tagged k s a

expm1 :: Tagged k s a -> Tagged k s a

log1pexp :: Tagged k s a -> Tagged k s a

log1mexp :: Tagged k s a -> Tagged k s a

Fractional a => Fractional (Tagged k s a)

Methods

(/) :: Tagged k s a -> Tagged k s a -> Tagged k s a

recip :: Tagged k s a -> Tagged k s a

fromRational :: Rational -> Tagged k s a

Integral a => Integral (Tagged k s a)

Methods

quot :: Tagged k s a -> Tagged k s a -> Tagged k s a

rem :: Tagged k s a -> Tagged k s a -> Tagged k s a

div :: Tagged k s a -> Tagged k s a -> Tagged k s a

mod :: Tagged k s a -> Tagged k s a -> Tagged k s a

quotRem :: Tagged k s a -> Tagged k s a -> (Tagged k s a, Tagged k s a)

divMod :: Tagged k s a -> Tagged k s a -> (Tagged k s a, Tagged k s a)

toInteger :: Tagged k s a -> Integer

(Data s, Data b) => Data (Tagged * s b)

Methods

gfoldl :: (forall d a. Data d => c (d -> a) -> d -> c a) -> (forall g. g -> c g) -> Tagged * s b -> c (Tagged * s b)

gunfold :: (forall a r. Data a => c (a -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (Tagged * s b)

toConstr :: Tagged * s b -> Constr

dataTypeOf :: Tagged * s b -> DataType

dataCast1 :: Typeable (* -> *) t => (forall d. Data d => c (t d)) -> Maybe (c (Tagged * s b))

dataCast2 :: Typeable (* -> * -> *) t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (Tagged * s b))

gmapT :: (forall a. Data a => a -> a) -> Tagged * s b -> Tagged * s b

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Tagged * s b -> r

gmapQr :: (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Tagged * s b -> r

gmapQ :: (forall d. Data d => d -> u) -> Tagged * s b -> [u]

gmapQi :: Int -> (forall d. Data d => d -> u) -> Tagged * s b -> u

gmapM :: Monad m => (forall d. Data d => d -> m d) -> Tagged * s b -> m (Tagged * s b)

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Tagged * s b -> m (Tagged * s b)

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Tagged * s b -> m (Tagged * s b)

Num a => Num (Tagged k s a)

Methods

(+) :: Tagged k s a -> Tagged k s a -> Tagged k s a

(-) :: Tagged k s a -> Tagged k s a -> Tagged k s a

(*) :: Tagged k s a -> Tagged k s a -> Tagged k s a

negate :: Tagged k s a -> Tagged k s a

abs :: Tagged k s a -> Tagged k s a

signum :: Tagged k s a -> Tagged k s a

fromInteger :: Integer -> Tagged k s a

Ord b => Ord (Tagged k s b)

Methods

compare :: Tagged k s b -> Tagged k s b -> Ordering

(<) :: Tagged k s b -> Tagged k s b -> Bool

(<=) :: Tagged k s b -> Tagged k s b -> Bool

(>) :: Tagged k s b -> Tagged k s b -> Bool

(>=) :: Tagged k s b -> Tagged k s b -> Bool

max :: Tagged k s b -> Tagged k s b -> Tagged k s b

min :: Tagged k s b -> Tagged k s b -> Tagged k s b

Read b => Read (Tagged k s b)

Methods

readsPrec :: Int -> ReadS (Tagged k s b)

readList :: ReadS [Tagged k s b]

readPrec :: ReadPrec (Tagged k s b)

readListPrec :: ReadPrec [Tagged k s b]

Real a => Real (Tagged k s a)

Methods

toRational :: Tagged k s a -> Rational

RealFloat a => RealFloat (Tagged k s a)

Methods

floatRadix :: Tagged k s a -> Integer

floatDigits :: Tagged k s a -> Int

floatRange :: Tagged k s a -> (Int, Int)

decodeFloat :: Tagged k s a -> (Integer, Int)

encodeFloat :: Integer -> Int -> Tagged k s a

exponent :: Tagged k s a -> Int

significand :: Tagged k s a -> Tagged k s a

scaleFloat :: Int -> Tagged k s a -> Tagged k s a

isNaN :: Tagged k s a -> Bool

isInfinite :: Tagged k s a -> Bool

isDenormalized :: Tagged k s a -> Bool

isNegativeZero :: Tagged k s a -> Bool

isIEEE :: Tagged k s a -> Bool

atan2 :: Tagged k s a -> Tagged k s a -> Tagged k s a

RealFrac a => RealFrac (Tagged k s a)

Methods

properFraction :: Integral b => Tagged k s a -> (b, Tagged k s a)

truncate :: Integral b => Tagged k s a -> b

round :: Integral b => Tagged k s a -> b

ceiling :: Integral b => Tagged k s a -> b

floor :: Integral b => Tagged k s a -> b

Show b => Show (Tagged k s b)

Methods

showsPrec :: Int -> Tagged k s b -> ShowS

show :: Tagged k s b -> String

showList :: [Tagged k s b] -> ShowS

Ix b => Ix (Tagged k s b)

Methods

range :: (Tagged k s b, Tagged k s b) -> [Tagged k s b]

index :: (Tagged k s b, Tagged k s b) -> Tagged k s b -> Int

unsafeIndex :: (Tagged k s b, Tagged k s b) -> Tagged k s b -> Int

inRange :: (Tagged k s b, Tagged k s b) -> Tagged k s b -> Bool

rangeSize :: (Tagged k s b, Tagged k s b) -> Int

unsafeRangeSize :: (Tagged k s b, Tagged k s b) -> Int

IsString a => IsString (Tagged k s a)

Methods

fromString :: String -> Tagged k s a

Generic (Tagged k s b)

Associated Types

type Rep (Tagged k s b) :: * -> *

Methods

from :: Tagged k s b -> Rep (Tagged k s b) x

to :: Rep (Tagged k s b) x -> Tagged k s b

Semigroup a => Semigroup (Tagged k s a)

Methods

(<>) :: Tagged k s a -> Tagged k s a -> Tagged k s a

sconcat :: NonEmpty (Tagged k s a) -> Tagged k s a

stimes :: Integral b => b -> Tagged k s a -> Tagged k s a

(Semigroup a, Monoid a) => Monoid (Tagged k s a)

Methods

mempty :: Tagged k s a

mappend :: Tagged k s a -> Tagged k s a -> Tagged k s a

mconcat :: [Tagged k s a] -> Tagged k s a

Storable a => Storable (Tagged k s a)

Methods

sizeOf :: Tagged k s a -> Int

alignment :: Tagged k s a -> Int

peekElemOff :: Ptr (Tagged k s a) -> Int -> IO (Tagged k s a)

pokeElemOff :: Ptr (Tagged k s a) -> Int -> Tagged k s a -> IO ()

peekByteOff :: Ptr b -> Int -> IO (Tagged k s a)

pokeByteOff :: Ptr b -> Int -> Tagged k s a -> IO ()

peek :: Ptr (Tagged k s a) -> IO (Tagged k s a)

poke :: Ptr (Tagged k s a) -> Tagged k s a -> IO ()

Bits a => Bits (Tagged k s a)

Methods

(.&.) :: Tagged k s a -> Tagged k s a -> Tagged k s a

(.|.) :: Tagged k s a -> Tagged k s a -> Tagged k s a

xor :: Tagged k s a -> Tagged k s a -> Tagged k s a

complement :: Tagged k s a -> Tagged k s a

shift :: Tagged k s a -> Int -> Tagged k s a

rotate :: Tagged k s a -> Int -> Tagged k s a

zeroBits :: Tagged k s a

bit :: Int -> Tagged k s a

setBit :: Tagged k s a -> Int -> Tagged k s a

clearBit :: Tagged k s a -> Int -> Tagged k s a

complementBit :: Tagged k s a -> Int -> Tagged k s a

testBit :: Tagged k s a -> Int -> Bool

bitSizeMaybe :: Tagged k s a -> Maybe Int

bitSize :: Tagged k s a -> Int

isSigned :: Tagged k s a -> Bool

shiftL :: Tagged k s a -> Int -> Tagged k s a

unsafeShiftL :: Tagged k s a -> Int -> Tagged k s a

shiftR :: Tagged k s a -> Int -> Tagged k s a

unsafeShiftR :: Tagged k s a -> Int -> Tagged k s a

rotateL :: Tagged k s a -> Int -> Tagged k s a

rotateR :: Tagged k s a -> Int -> Tagged k s a

popCount :: Tagged k s a -> Int

FiniteBits a => FiniteBits (Tagged k s a)

Methods

finiteBitSize :: Tagged k s a -> Int

countLeadingZeros :: Tagged k s a -> Int

countTrailingZeros :: Tagged k s a -> Int

NFData b => NFData (Tagged k s b)

Methods

rnf :: Tagged k s b -> ()

type Rep1 (Tagged k s)

type Rep1 (Tagged k s) = D1 (MetaData "Tagged" "Data.Tagged" "tagged-0.8.4-9gtrXrOYlY5BIFTjUM7KTh" True) (C1 (MetaCons "Tagged" PrefixI True) (S1 (MetaSel (Just Symbol "unTagged") NoSourceUnpackedness NoSourceStrictness DecidedLazy) Par1))

type Rep (Tagged k s b)

type Rep (Tagged k s b) = D1 (MetaData "Tagged" "Data.Tagged" "tagged-0.8.4-9gtrXrOYlY5BIFTjUM7KTh" True) (C1 (MetaCons "Tagged" PrefixI True) (S1 (MetaSel (Just Symbol "unTagged") NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 b)))

retag :: Tagged s b -> Tagged t b

Some times you need to change the tag you have lying around. Idiomatic usage is to make a new combinator for the relationship between the tags that you want to enforce, and define that combinator using retag.

data Succ n
retagSucc :: Tagged n a -> Tagged (Succ n) a
retagSucc = retag

untag :: Tagged s b -> b

Alias for unTagged

tagSelf :: a -> Tagged a a

Tag a value with its own type.

untagSelf :: Tagged a a -> a

untagSelf is a type-restricted version of untag.

asTaggedTypeOf :: s -> tagged s b -> s

asTaggedTypeOf is a type-restricted version of const. It is usually used as an infix operator, and its typing forces its first argument (which is usually overloaded) to have the same type as the tag of the second.

witness :: Tagged a b -> a -> b

Conversion

proxy :: Tagged s a -> proxy s -> a

Convert from a Tagged representation to a representation based on a Proxy.

unproxy :: (Proxy s -> a) -> Tagged s a

Convert from a representation based on a Proxy to a Tagged representation.

tagWith :: proxy s -> a -> Tagged s a

Another way to convert a proxy to a tag.

Proxy methods GHC dropped

reproxy :: proxy a -> Proxy b

Some times you need to change the proxy you have lying around. Idiomatic usage is to make a new combinator for the relationship between the proxies that you want to enforce, and define that combinator using reproxy.

data Succ n
reproxySucc :: proxy n -> Proxy (Succ n)
reproxySucc = reproxy