sort: sorting and merging lists

value sort : ('a -> 'a -> bool) -> 'a list -> 'a list
Sort a list in increasing order according to an ordering predicate. The predicate should return true if its first argument is less than or equal to its second argument.
value merge : ('a -> 'a -> bool) -> 'a list -> 'a list -> 'a list
Merge two lists according to the given predicate. Assuming the two argument lists are sorted according to the predicate, merge returns a sorted list containing the elements from the two lists. The behavior is undefined if the two argument lists were not sorted.