not package:foundation

Boolean "not"

Check if a collection does *not* contain a specific element This is the inverse of elem.

meaning the parser was short of CountOf Element of input.

The parser needed more data, only when using parseOnly

The isNothing function returns True iff its argument is Nothing.

Examples

Basic usage:

>>> isNothing (Just 3)
False

>>> isNothing (Just ())
False

>>> isNothing Nothing
True

Only the outer constructor is taken into consideration:

>>> isNothing (Just Nothing)
False