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Structure Intset
(* Intset -- applicative sets of integers *)
(* From SML/NJ lib 0.2, copyright 1993 by AT&T Bell Laboratories *)
(* Original implementation due to Stephen Adams, Southampton, UK *)
type intset
exception NotFound
val empty : intset
val singleton : int -> intset
val add : intset * int -> intset
val addList : intset * int list -> intset
val isEmpty : intset -> bool
val equal : intset * intset -> bool
val isSubset : intset * intset -> bool
val member : intset * int -> bool
val delete : intset * int -> intset
val numItems : intset -> int
val union : intset * intset -> intset
val intersection : intset * intset -> intset
val difference : intset * intset -> intset
val listItems : intset -> int list
val app : (int -> unit) -> intset -> unit
val revapp : (int -> unit) -> intset -> unit
val foldr : (int * 'b -> 'b) -> 'b -> intset -> 'b
val foldl : (int * 'b -> 'b) -> 'b -> intset -> 'b
val find : (int -> bool) -> intset -> int option
(*
[intset] is the type of sets of integers.
[empty] is the empty set of integers.
[singleton i] is the singleton set containing i.
[add(s, i)] adds item i to set s.
[addList(s, xs)] adds all items from the list xs to the set s.
[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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