typelevel-1.0.4: Useful type level operations (type families and related operators).

Safe HaskellNone
LanguageHaskell2010

Type.Maybe

Documentation

type family IsJust a Source

Equations

IsJust (Just a) = True 
IsJust a = False 

type family CatMaybes lst :: [k] Source

Equations

CatMaybes `[]` = `[]` 
CatMaybes (Just a : ms) = a : CatMaybes ms 
CatMaybes (Nothing : ms) = CatMaybes ms