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Maybe

Functions to work with maybe values.

just()
Create a 'Just' variant of a maybe value
nothing()
Create a 'Nothing' variant of a maybe value
maybe()
Modify a function to return a maybe value
perhaps()
Modify a function to return the value or a default value
and_then() bind()
Evaluate a maybe returning function on a maybe value
maybe_map() fmap()
Evaluate a function on a maybe value
maybe_map2()
Evaluate a binary function on two maybe values
maybe_flatten() join()
Flatten a nested maybe value
maybe_contains()
Check if a maybe value contains a specific value
maybe_equal()
Check if two maybe values are equal
maybe_case()
Unwrap and call a function on a maybe value or return a default
with_default() from_maybe()
Unwrap a maybe value or return a default
from_just()
Unwrap a 'Just' value or throw an error
filter_justs()
Filter and unwrap a list of 'Just' values
filter_map()
Map a function over a list and filter only 'Just' values
is_maybe()
Check if an object is a maybe value
is_just()
Check if an object is a 'Just' value
is_nothing()
Check if an object is a 'Nothing' value

Predicates

Predicate functions to assert properties of a return value.

not_empty()
Check if a vector or data frame is empty
not_undefined()
Check if an object is not undefined
not_null()
Check if an object is not NULL
not_na()
Check if an object is not NA
not_nan()
Check if an object is not NaN
not_infinite()
Check if an object is not infinite
and()
Combine predicate functions to check if all are TRUE
or()
Combine predicate functions to check if any are TRUE