cats.monad.maybe
The Maybe monad implementation and helpers functions for working with maybe related types.
(require '[cats.monad.maybe :as maybe])
(maybe/just 1)
;; => #<Just [1]>
cat-maybes
(cat-maybes coll)Given a collection of maybes, return a sequence of the values that the just’s contain.
from-maybe
(from-maybe mv)(from-maybe mv default)Return inner value from maybe monad.
This is a specialized version of cats.core/extract for Maybe monad types that allows set up the default value.
Let see some examples:
(from-maybe (just 1))
;=> 1
(from-maybe (nothing))
;=> nil
(from-maybe (nothing) 42)
;=> 42
map->Just
(map->Just m__7585__auto__)Factory function for class cats.monad.maybe.Just, taking a map of keywords to field values.
map->Nothing
(map->Nothing m__7585__auto__)Factory function for class cats.monad.maybe.Nothing, taking a map of keywords to field values.
map-maybe
(map-maybe mf coll)Given a maybe-returning function and a collection, map the function over the collection returning the values contained in the just values of the resulting collection.
maybe
macro
(maybe default m f)Given a default value, a maybe and a function, return the default if the maybe is a nothing; if its a just, apply the function to the value it contains and return the result.
maybe->seq
(maybe->seq m)Given a maybe, return an empty seq if its nothing or a one-element seq with its value if its not.
seq->maybe
(seq->maybe coll)Given a collection, return a nothing if its empty or a just with its first element if its not.