SRFI 189 is now in final status.This SRFI defines two disjoint immutable container types known as Maybe and Either, both of which can contain objects collectively known as their payload. A Maybe object is either a Just object or the unique object Nothing (which has no payload); an Either object is either a Right object or a Left object. Maybe represents the concept of optional values; Either represents the concept of values which are either correct (Right) or errors (Left). Note that the term...
