nothing is:exact
Analogous to
Nothing and equivalent to
mzero
nothing :: Prism' (Maybe a) ()
A prism on the
Nothing element of a
Maybe.
Match nothing, universal rejector.
>>> prove $ \(s :: SString) -> sNot (s `match` nothing)
Q.E.D.
Record with polymorphic phantom type of SQL null value. Semantics of
comparing is unsafe.
Assert that some value is Nothing.
A predicate checking if the input is Nothing
>>> Nothing `shouldSatisfy` P.nothing
This doesn't modify the config in any way. It's just here for your
initial config because Haskell doesn't allow empty do-blocks. Feel
free to delete it once you've added other stuff.
A Predicate that accepts
Maybe values of
Nothing. Unlike
eq, this doesn't require
Eq or
Show instances.
>>> accept nothing Nothing
True
>>> accept nothing (Just "something")
False