(* int-list-map.sml
*
* COPYRIGHT (c) 1996 by AT&T Research. See COPYRIGHT file for details.
*
* An implementation of finite maps on integer keys, which uses a sorted list
* representation.
*)
structure IntListMap :> ORD_MAP where type Key.ord_key = Int.int =
struct
structure Key =
struct
type ord_key = int
val compare = Int.compare
end
type 'a map = (int * 'a) list
val empty = []
fun isEmpty [] = true
| isEmpty _ = false
(* return the first item in the map (or NONE if it is empty) *)
fun first [] = NONE
| first ((_, value)::_) = SOME value
(* return the first item in the map and its key (or NONE if it is empty) *)
fun firsti [] = NONE
| firsti ((key, value)::_) = SOME(key, value)
fun singleton (key, item) = [(key, item)]
fun insert (l, key, item) = let
fun f [] = [(key, item)]
| f ((elem as (key', _))::r) = (case Key.compare(key, key')
of LESS => (key, item) :: elem :: r
| EQUAL => (key, item) :: r
| GREATER => elem :: (f r)
(* end case *))
in
f l
end
fun insert' ((k, x), m) = insert(m, k, x)
(* return true if the key is in the map's domain *)
fun inDomain (l, key) = let
fun f [] = false
| f ((key', x) :: r) = (key' <= key) andalso ((key' = key) orelse f r)
in
f l
end
(* Look for an item, return NONE if the item doesn't exist *)
fun find (l, key) = let
fun f [] = NONE
| f ((key', x) :: r) =
if (key < key') then NONE
else if (key = key') then SOME x
else f r
in
f l
end
(* Remove an item, returning new map and value removed.
* Raise LibBase.NotFound if not found.
*)
fun remove (l, key) = let
fun f (_, []) = raise LibBase.NotFound
| f (prefix, (elem as (key', x)) :: r) = (case Key.compare(key, key')
of LESS => raise LibBase.NotFound
| EQUAL => (List.revAppend(prefix, r), x)
| GREATER => f(elem :: prefix, r)
(* end case *))
in
f ([], l)
end
(* Return the number of items in the map *)
fun numItems l = List.length l
(* Return a list of the items (and their keys) in the map *)
fun listItems (l : 'a map) = List.map #2 l
fun listItemsi l = l
fun listKeys (l : 'a map) = List.map #1 l
fun collate cmpRng = let
fun cmp ([], []) = EQUAL
| cmp ([], _) = LESS
| cmp (_, []) = GREATER
| cmp ((x1, y1)::r1, (x2, y2)::r2) = (case Key.compare(x1, x2)
of EQUAL => (case cmpRng(y1, y2)
of EQUAL => cmp (r1, r2)
| order => order
(* end case *))
| order => order
(* end case *))
in
cmp
end
(* return a map whose domain is the union of the domains of the two input
* maps, using the supplied function to define the map on elements that
* are in both domains.
*)
fun unionWith f (m1 : 'a map, m2 : 'a map) = let
fun merge ([], [], l) = List.rev l
| merge ([], m2, l) = List.revAppend(l, m2)
| merge (m1, [], l) = List.revAppend(l, m1)
| merge (m1 as ((k1, x1)::r1), m2 as ((k2, x2)::r2), l) = (
case Key.compare (k1, k2)
of LESS => merge (r1, m2, (k1, x1)::l)
| EQUAL => merge (r1, r2, (k1, f(x1, x2)) :: l)
| GREATER => merge (m1, r2, (k2, x2)::l)
(* end case *))
in
merge (m1, m2, [])
end
fun unionWithi f (m1 : 'a map, m2 : 'a map) = let
fun merge ([], [], l) = List.rev l
| merge ([], m2, l) = List.revAppend(l, m2)
| merge (m1, [], l) = List.revAppend(l, m1)
| merge (m1 as ((k1, x1)::r1), m2 as ((k2, x2)::r2), l) = (
case Key.compare (k1, k2)
of LESS => merge (r1, m2, (k1, x1)::l)
| EQUAL => merge (r1, r2, (k1, f(k1, x1, x2)) :: l)
| GREATER => merge (m1, r2, (k2, x2)::l)
(* end case *))
in
merge (m1, m2, [])
end
(* return a map whose domain is the intersection of the domains of the
* two input maps, using the supplied function to define the range.
*)
fun intersectWith f (m1 : 'a map, m2 : 'b map) = let
fun merge (m1 as ((k1, x1)::r1), m2 as ((k2, x2)::r2), l) = (
case Key.compare (k1, k2)
of LESS => merge (r1, m2, l)
| EQUAL => merge (r1, r2, (k1, f(x1, x2)) :: l)
| GREATER => merge (m1, r2, l)
(* end case *))
| merge (_, _, l) = List.rev l
in
merge (m1, m2, [])
end
fun intersectWithi f (m1 : 'a map, m2 : 'b map) = let
fun merge (m1 as ((k1, x1)::r1), m2 as ((k2, x2)::r2), l) = (
case Key.compare (k1, k2)
of LESS => merge (r1, m2, l)
| EQUAL => merge (r1, r2, (k1, f(k1, x1, x2)) :: l)
| GREATER => merge (m1, r2, l)
(* end case *))
| merge (_, _, l) = List.rev l
in
merge (m1, m2, [])
end
fun mergeWith f (m1 : 'a map, m2 : 'b map) = let
fun merge (m1 as ((k1, x1)::r1), m2 as ((k2, x2)::r2), l) =
if (k1 < k2)
then mergef (k1, SOME x1, NONE, r1, m2, l)
else if (k1 = k2)
then mergef (k1, SOME x1, SOME x2, r1, r2, l)
else mergef (k2, NONE, SOME x2, m1, r2, l)
| merge ([], [], l) = List.rev l
| merge ((k1, x1)::r1, [], l) = mergef (k1, SOME x1, NONE, r1, [], l)
| merge ([], (k2, x2)::r2, l) = mergef (k2, NONE, SOME x2, [], r2, l)
and mergef (k, x1, x2, r1, r2, l) = (case f (x1, x2)
of NONE => merge (r1, r2, l)
| SOME y => merge (r1, r2, (k, y)::l)
(* end case *))
in
merge (m1, m2, [])
end
fun mergeWithi f (m1 : 'a map, m2 : 'b map) = let
fun merge (m1 as ((k1, x1)::r1), m2 as ((k2, x2)::r2), l) =
if (k1 < k2)
then mergef (k1, SOME x1, NONE, r1, m2, l)
else if (k1 = k2)
then mergef (k1, SOME x1, SOME x2, r1, r2, l)
else mergef (k2, NONE, SOME x2, m1, r2, l)
| merge ([], [], l) = List.rev l
| merge ((k1, x1)::r1, [], l) = mergef (k1, SOME x1, NONE, r1, [], l)
| merge ([], (k2, x2)::r2, l) = mergef (k2, NONE, SOME x2, [], r2, l)
and mergef (k, x1, x2, r1, r2, l) = (case f (k, x1, x2)
of NONE => merge (r1, r2, l)
| SOME y => merge (r1, r2, (k, y)::l)
(* end case *))
in
merge (m1, m2, [])
end
(* Apply a function to the entries of the map in map order. *)
val appi = List.app
fun app f l = appi (fn (_, item) => f item) l
(* Create a new table by applying a map function to the
* name/value pairs in the table.
*)
fun mapi f l = List.map (fn (key, item) => (key, f(key, item))) l
fun map f l = List.map (fn (key, item) => (key, f item)) l
(* Apply a folding function to the entries of the map
* in increasing map order.
*)
fun foldli f init l =
List.foldl (fn ((key, item), accum) => f(key, item, accum)) init l
fun foldl f init l = List.foldl (fn ((_, item), accum) => f(item, accum)) init l
(* Apply a folding function to the entries of the map
* in decreasing map order.
*)
fun foldri f init l =
List.foldr (fn ((key, item), accum) => f(key, item, accum)) init l
fun foldr f init l = List.foldr (fn ((_, item), accum) => f(item, accum)) init l
fun filter pred l = List.filter (fn (_, item) => pred item) l
fun filteri pred l = List.filter pred l
fun mapPartiali f l = let
fun f' (key, item) = (case f (key, item)
of NONE => NONE
| SOME y => SOME(key, y)
(* end case *))
in
List.mapPartial f' l
end
fun mapPartial f l = mapPartiali (fn (_, item) => f item) l
end (* IntListMap *)