chickadee » srfi-113 » set-map

Applies proc to each element of set in arbitrary order and returns a newly allocated set, created as if by (set comparator), which contains the results of the applications. For example:

(set-map string-ci-comparator symbol->string (set eq? 'foo 'bar 'baz))
     => (set string-ci-comparator "foo" "bar" "baz")

Note that, when proc defines a mapping that is not 1:1, some of the mapped objects may be equivalent in the sense of comparator's equality predicate, and in this case duplicate elements are omitted as in the set constructor. For example:

(set-map (lambda (x) (quotient x 2))
         integer-comparator
         (set integer-comparator 1 2 3 4 5))
 => (set integer-comparator 0 1 2)

If the elements are the same in the sense of eqv?, it is unpredictable which one will be preserved in the result.