# Structure Splayset

Identifier index | Structure index
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    (* Splayset -- applicative sets implemented by splay-trees       *)
    (* From SML/NJ lib 0.2, copyright 1993 by AT&T Bell Laboratories *)

    type 'item set

    exception NotFound

    val empty        : ('_item * '_item -> order) -> '_item set
    val singleton    : ('_item * '_item -> order) -> '_item -> '_item set
    val add          : '_item set * '_item -> '_item set
    val addList      : '_item set * '_item list -> '_item set
    val retrieve     : 'item set * 'item -> 'item
    val peek         : 'item set * 'item -> 'item option
    val isEmpty      : 'item set -> bool
    val equal        : 'item set * 'item set -> bool
    val isSubset     : 'item set * 'item set -> bool
    val member       : 'item set * 'item -> bool
    val delete       : '_item set * '_item -> '_item set
    val numItems     : 'item set ->  int
    val union        : '_item set * '_item set -> '_item set
    val intersection : '_item set * '_item set -> '_item set
    val difference   : '_item set * '_item set -> '_item set
    val listItems    : 'item set -> 'item list
    val app          : ('item -> unit) -> 'item set -> unit
    val revapp       : ('item -> unit) -> 'item set -> unit
    val foldr        : ('item * 'b -> 'b) -> 'b -> 'item set -> 'b
    val foldl        : ('item * 'b -> 'b) -> 'b -> 'item set -> 'b
    val find         : ('item -> bool) -> 'item set -> 'item option

    (*
       ['item set] is the type of sets of ordered elements of type 'item.
       The ordering relation on the elements is used in the representation
       of the set.  The result of combining two sets with different
       underlying ordering relations is undefined.  The implementation
       uses splay-trees (Sleator and Tarjan).

       [empty ordr] creates a new empty set with the given ordering
       relation.

       [singleton ordr i] creates the singleton set containing i, with the
       given ordering relation.

       [add(s, i)] adds item i to set s.

       [addList(s, xs)] adds all items from the list xs to the set s.

       [retrieve(s, i)] returns i if it is in s; raises NotFound otherwise.

       [peek(s, i)] returns SOME i if i is in s; returns NONE otherwise.

       [isEmpty s] returns true if and only if the set is empty.

       [equal(s1, s2)] returns true if and only if the two sets have the
       same elements.

       [isSubset(s1, s2)] returns true if and only if s1 is a subset of s2.

       [member(s, i)] returns true if and only if i is in s.

       [delete(s, i)] removes item i from s.  Raises NotFound if i is not in s.

       [numItems s] returns the number of items in set s.

       [union(s1, s2)] returns the union of s1 and s2.

       [intersection(s1, s2)] returns the intersectionof s1 and s2.

       [difference(s1, s2)] returns the difference between s1 and s2 (that
       is, the set of elements in s1 but not in s2).

       [listItems s] returns a list of the items in set s, in increasing
        order.

       [app f s] applies function f to the elements of s, in increasing
       order.

       [revapp f s] applies function f to the elements of s, in decreasing
       order.

       [foldl f e s] applies the folding function f to the entries of the
       set in increasing order.

       [foldr f e s] applies the folding function f to the entries of the
       set in decreasing order.

       [find p s] returns SOME i, where i is an item in s which satisfies
       p, if one exists; otherwise returns NONE.
    *)

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Moscow ML 2.00