- mapping-replace mapping key valueprocedure
The mapping-replace procedure returns a newly allocated mapping that uses the same comparator as the mapping mapping and contains all the associations of mapping except as follows: If key is equal (in the sense of mapping's comparator) to an existing key of mapping, then the association for that key is omitted and replaced the association defined by the pair key and value. If there is no such key in mapping, then mapping is returned unchanged.