- (string-map proc s [start end]) -> stringprocedure
- (string-map! proc s [start end]) -> unspecifiedprocedure
PROC is a char->char procedure; it is mapped over S.
string-map returns the result string and does not alter its S parameter. string-map! is the in-place side-effecting variant.
Note: The order in which PROC is applied to the elements of S is not specified.