tagged-0.8.5: Haskell 98 phantom types to avoid unsafely passing dummy arguments

Copyright2009-2015 Edward Kmett
LicenseBSD3
MaintainerEdward Kmett <ekmett@gmail.com>
Stabilityexperimental
Portabilityportable
Safe HaskellSafe
LanguageHaskell98

Data.Tagged

Contents

Description

 

Synopsis

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

Instances

Eq2 (Tagged *) # 

Methods

liftEq2 :: (a -> b -> Bool) -> (c -> d -> Bool) -> Tagged * a c -> Tagged * b d -> Bool #

Ord2 (Tagged *) # 

Methods

liftCompare2 :: (a -> b -> Ordering) -> (c -> d -> Ordering) -> Tagged * a c -> Tagged * b d -> Ordering #

Read2 (Tagged *) # 

Methods

liftReadsPrec2 :: (Int -> ReadS a) -> ReadS [a] -> (Int -> ReadS b) -> ReadS [b] -> Int -> ReadS (Tagged * a b) #

liftReadList2 :: (Int -> ReadS a) -> ReadS [a] -> (Int -> ReadS b) -> ReadS [b] -> ReadS [Tagged * a b] #

Show2 (Tagged *) # 

Methods

liftShowsPrec2 :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> (Int -> b -> ShowS) -> ([b] -> ShowS) -> Int -> Tagged * a b -> ShowS #

liftShowList2 :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> (Int -> b -> ShowS) -> ([b] -> ShowS) -> [Tagged * a b] -> ShowS #

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 #

Eq1 (Tagged k s) # 

Methods

liftEq :: (a -> b -> Bool) -> Tagged k s a -> Tagged k s b -> Bool #

Ord1 (Tagged k s) # 

Methods

liftCompare :: (a -> b -> Ordering) -> Tagged k s a -> Tagged k s b -> Ordering #

Read1 (Tagged k s) # 

Methods

liftReadsPrec :: (Int -> ReadS a) -> ReadS [a] -> Int -> ReadS (Tagged k s a) #

liftReadList :: (Int -> ReadS a) -> ReadS [a] -> ReadS [Tagged k s a] #

Show1 (Tagged k s) # 

Methods

liftShowsPrec :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> Int -> Tagged k s a -> ShowS #

liftShowList :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> [Tagged k s a] -> ShowS #

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-0.8.5-jDBtbBndklGIlXZjVMhpH" 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-0.8.5-jDBtbBndklGIlXZjVMhpH" 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