map
compose(map(toString), map(inc), Maybe.of)(5) //=> Maybe.Just("6")
Maybe.of(5).map(compose(toString, inc)) //=> Maybe.Just("6")
//////////////////////////////////////////////////////////////////
map(concat, identity)('a')('b') //=> "ab"
map(concat('b'), identity)('a') //=> "ba"
map(concat, concat)('a')('b')('c') //=> "abc"