## `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.