Safe Haskell	None
Language	GHC2024

GHC.Data.Unboxed

Synopsis

data MaybeUB a :: TYPE ('SumRep '[ZeroBitRep, LiftedRep]) where
- pattern JustUB :: a -> MaybeUB a
- pattern NothingUB :: MaybeUB a
fmapMaybeUB :: (a -> b) -> MaybeUB a -> MaybeUB b
fromMaybeUB :: a -> MaybeUB a -> a
apMaybeUB :: MaybeUB (a -> b) -> MaybeUB a -> MaybeUB b
maybeUB :: b -> (a -> b) -> MaybeUB a -> b
traverseMaybeUB :: (a -> Maybe b) -> [a] -> Maybe [b]

Documentation

data MaybeUB a :: TYPE ('SumRep '[ZeroBitRep, LiftedRep]) where Source #

Like Maybe, but using unboxed sums.

Use with care. Using a unboxed maybe is not always a win in execution *time* even when allocations go down. So make sure to benchmark for execution time as well. If the difference in *runtime* for the compiler is too small to measure it's likely better to use a regular Maybe instead.

This is since it causes more function arguments to be passed, and potentially more variables to be captured by closures increasing closure size.

Bundled Patterns

pattern JustUB :: a -> MaybeUB a
pattern NothingUB :: MaybeUB a

fmapMaybeUB :: (a -> b) -> MaybeUB a -> MaybeUB b Source #

fromMaybeUB :: a -> MaybeUB a -> a Source #

apMaybeUB :: MaybeUB (a -> b) -> MaybeUB a -> MaybeUB b Source #

maybeUB :: b -> (a -> b) -> MaybeUB a -> b Source #

traverseMaybeUB Source #

Arguments

:: (a -> Maybe b)	`INLINE` function to map over the list
-> [a]
-> Maybe [b]

Like traverse for the Maybe applicative, but avoiding intermediate allocations.

The passed-in function must inline for this to help at all.