--- /dev/null
+;; -*-Scheme-*-
+;;
+;; $Id: wttree.scm,v 1.1 1995/09/29 17:50:10 adams Exp $
+;;
+;; Copyright (c) 1993-1994 Stephen Adams
+;;
+;; References:
+;;
+;; Stephen Adams, Implemeting Sets Efficiently in a Functional
+;; Language, CSTR 92-10, Department of Electronics and Computer
+;; Science, University of Southampton, 1992
+;;
+;;
+;; Copyright (c) 1993-94 Massachusetts Institute of Technology
+;;
+;; This material was developed by the Scheme project at the Massachusetts
+;; Institute of Technology, Department of Electrical Engineering and
+;; Computer Science. Permission to copy this software, to redistribute
+;; it, and to use it for any purpose is granted, subject to the following
+;; restrictions and understandings.
+;;
+;; 1. Any copy made of this software must include this copyright notice
+;; in full.
+;;
+;; 2. Users of this software agree to make their best efforts (a) to
+;; return to the MIT Scheme project any improvements or extensions that
+;; they make, so that these may be included in future releases; and (b)
+;; to inform MIT of noteworthy uses of this software.
+;;
+;; 3. All materials developed as a consequence of the use of this
+;; software shall duly acknowledge such use, in accordance with the usual
+;; standards of acknowledging credit in academic research.
+;;
+;; 4. MIT has made no warrantee or representation that the operation of
+;; this software will be error-free, and MIT is under no obligation to
+;; provide any services, by way of maintenance, update, or otherwise.
+;;
+;; 5. In conjunction with products arising from the use of this material,
+;; there shall be no use of the name of the Massachusetts Institute of
+;; Technology nor of any adaptation thereof in any advertising,
+;; promotional, or sales literature without prior written consent from
+;; MIT in each case.
+\f
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;;
+;; Weight Balanced Binary Trees
+;;
+;;
+;;
+;; This file has been modified from the MIT-Scheme library version to
+;; make it more standard. The main changes are
+;;
+;; . The whole thing has been put in a LET as R4RS Scheme has no module
+;; system.
+;; . The MIT-Scheme define structure operations have been written out by
+;; hand.
+;;
+;; It has been tested on MIT-Scheme, scheme48 and scm4e1
+;;
+;; Non-standard procedures:
+;; error
+;; error:wrong-type-argument
+;; error:band-range-argument
+;; These are only called when there is an error so it is not critical to
+;; have them defined :-)
+;;
+;;
+;; If your system has a compiler and you want this code to run fast, you
+;; should do whatever is necessary to inline all of the structure accessors.
+;;
+;; This is MIT-Scheme's way of saying that +, car etc should all be inlined.
+;;
+(declare (usual-integrations))
+
+\f
+;;;
+;;; Interface to this package.
+;;;
+;;; ONLY these procedures (and TEST at the end of the file) will be
+;;; (re)defined in your system.
+;;;
+
+(define make-wt-tree-type #f)
+(define number-wt-type #f)
+(define string-wt-type #f)
+
+(define make-wt-tree #f)
+(define singleton-wt-tree #f)
+(define alist->wt-tree #f)
+(define wt-tree/empty? #f)
+(define wt-tree/size #f)
+(define wt-tree/add #f)
+(define wt-tree/delete #f)
+(define wt-tree/add! #f)
+(define wt-tree/delete! #f)
+(define wt-tree/member? #f)
+(define wt-tree/lookup #f)
+(define wt-tree/split< #f)
+(define wt-tree/split> #f)
+(define wt-tree/union #f)
+(define wt-tree/intersection #f)
+(define wt-tree/difference #f)
+(define wt-tree/subset? #f)
+(define wt-tree/set-equal? #f)
+(define wt-tree/fold #f)
+(define wt-tree/for-each #f)
+(define wt-tree/index #f)
+(define wt-tree/index-datum #f)
+(define wt-tree/index-pair #f)
+(define wt-tree/rank #f)
+(define wt-tree/min #f)
+(define wt-tree/min-datum #f)
+(define wt-tree/min-pair #f)
+(define wt-tree/delete-min #f)
+(define wt-tree/delete-min! #f)
+
+
+;; This LET sets all of the above variables.
+
+(let ()
+
+ ;; We use the folowing MIT-Scheme operation on fixnums (small
+ ;; integers). R4RS compatible (but less efficient) definitions.
+ ;; You should replace these with something that is efficient in your
+ ;; system.
+
+ ;;(define fix:fixnum? (lambda (x) (and (exact? x) (integer? x))))
+ ;;(define fix:+ +)
+ ;;(define fix:- -)
+ ;;(define fix:< <)
+ ;;(define fix:<= <)
+ ;;(define fix:> >)
+ ;;(define fix:* *)
+
+ ;; A TREE-TYPE is a collection of those procedures that depend on the
+ ;; ordering relation.
+
+ ;; MIT-Scheme structure definition
+ ;;(define-structure
+ ;; (tree-type
+ ;; (conc-name tree-type/)
+ ;; (constructor %make-tree-type))
+ ;; (key<? #F read-only true)
+ ;; (alist->tree #F read-only true)
+ ;; (add #F read-only true)
+ ;; (insert! #F read-only true)
+ ;; (delete #F read-only true)
+ ;; (delete! #F read-only true)
+ ;; (member? #F read-only true)
+ ;; (lookup #F read-only true)
+ ;; (split-lt #F read-only true)
+ ;; (split-gt #F read-only true)
+ ;; (union #F read-only true)
+ ;; (intersection #F read-only true)
+ ;; (difference #F read-only true)
+ ;; (subset? #F read-only true)
+ ;; (rank #F read-only true)
+ ;;)
+
+ ;; Written out by hand, using vectors:
+ ;;
+ ;; If possible, you should teach your system to print out something
+ ;; like #[tree-type <] instread of the whole vector.
+
+ (define tag:tree-type (string->symbol "#[(runtime wttree)tree-type]"))
+
+ (define (%make-tree-type key<? alist->tree
+ add insert!
+ delete delete!
+ member? lookup
+ split-lt split-gt
+ union intersection
+ difference subset?
+ rank )
+ (vector tag:tree-type
+ key<? alist->tree add insert!
+ delete delete! member? lookup
+ split-lt split-gt union intersection
+ difference subset? rank ))
+
+ (define (tree-type? tt)
+ (and (vector? tt)
+ (eq? (vector-ref tt 0) tag:tree-type)))
+
+ (define (tree-type/key<? tt) (vector-ref tt 1))
+ (define (tree-type/alist->tree tt) (vector-ref tt 2))
+ (define (tree-type/add tt) (vector-ref tt 3))
+ (define (tree-type/insert! tt) (vector-ref tt 4))
+ (define (tree-type/delete tt) (vector-ref tt 5))
+ (define (tree-type/delete! tt) (vector-ref tt 6))
+ (define (tree-type/member? tt) (vector-ref tt 7))
+ (define (tree-type/lookup tt) (vector-ref tt 8))
+ (define (tree-type/split-lt tt) (vector-ref tt 9))
+ (define (tree-type/split-gt tt) (vector-ref tt 10))
+ (define (tree-type/union tt) (vector-ref tt 11))
+ (define (tree-type/intersection tt) (vector-ref tt 12))
+ (define (tree-type/difference tt) (vector-ref tt 13))
+ (define (tree-type/subset? tt) (vector-ref tt 14))
+ (define (tree-type/rank tt) (vector-ref tt 15))
+
+ ;; User level tree representation.
+ ;;
+ ;; WT-TREE is a wrapper for trees of nodes.
+ ;;
+ ;;MIT-Scheme:
+ ;;(define-structure
+ ;; (wt-tree
+ ;; (conc-name tree/)
+ ;; (constructor %make-wt-tree))
+ ;; (type #F read-only true)
+ ;; (root #F read-only false))
+
+ ;; If possible, you should teach your system to print out something
+ ;; like #[wt-tree] instread of the whole vector.
+
+ (define tag:wt-tree (string->symbol "#[(runtime wttree)wt-tree]"))
+
+ (define (%make-wt-tree type root)
+ (vector tag:wt-tree type root))
+
+ (define (wt-tree? t)
+ (and (vector? t)
+ (eq? (vector-ref t 0) tag:wt-tree)))
+
+ (define (tree/type t) (vector-ref t 1))
+ (define (tree/root t) (vector-ref t 2))
+ (define (set-tree/root! t v) (vector-set! t 2 v))
+
+ ;; Nodes are the thing from which the real trees are built. There are
+ ;; lots of these and the uninquisitibe user will never see them, so
+ ;; they are represented as untagged to save the slot that would be
+ ;; used for tagging structures.
+ ;; In MIT-Scheme these were all DEFINE-INTEGRABLE
+
+ (define (make-node k v l r w) (vector w l k r v))
+ (define (node/k node) (vector-ref node 2))
+ (define (node/v node) (vector-ref node 4))
+ (define (node/l node) (vector-ref node 1))
+ (define (node/r node) (vector-ref node 3))
+ (define (node/w node) (vector-ref node 0))
+
+ (define empty 'empty)
+ (define (empty? x) (eq? x 'empty))
+
+ (define (node/size node)
+ (if (empty? node) 0 (node/w node)))
+
+ (define (node/singleton k v) (make-node k v empty empty 1))
+
+ (define (with-n-node node receiver)
+ (receiver (node/k node) (node/v node) (node/l node) (node/r node)))
+
+ ;;
+ ;; Constructors for building node trees of various complexity
+ ;;
+
+ (define (n-join k v l r)
+ (make-node k v l r (fix:+ 1 (fix:+ (node/size l) (node/size r)))))
+
+ (define (single-l a.k a.v x r)
+ (with-n-node r
+ (lambda (b.k b.v y z) (n-join b.k b.v (n-join a.k a.v x y) z))))
+
+ (define (double-l a.k a.v x r)
+ (with-n-node r
+ (lambda (c.k c.v r.l z)
+ (with-n-node r.l
+ (lambda (b.k b.v y1 y2)
+ (n-join b.k b.v
+ (n-join a.k a.v x y1)
+ (n-join c.k c.v y2 z)))))))
+
+ (define (single-r b.k b.v l z)
+ (with-n-node l
+ (lambda (a.k a.v x y) (n-join a.k a.v x (n-join b.k b.v y z)))))
+
+ (define (double-r c.k c.v l z)
+ (with-n-node l
+ (lambda (a.k a.v x l.r)
+ (with-n-node l.r
+ (lambda (b.k b.v y1 y2)
+ (n-join b.k b.v
+ (n-join a.k a.v x y1)
+ (n-join c.k c.v y2 z)))))))
+
+ ;; (define-integrable wt-tree-ratio 5)
+ (define wt-tree-ratio 5)
+
+ (define (t-join k v l r)
+ (define (simple-join) (n-join k v l r))
+ (let ((l.n (node/size l))
+ (r.n (node/size r)))
+ (cond ((fix:< (fix:+ l.n r.n) 2) (simple-join))
+ ((fix:> r.n (fix:* wt-tree-ratio l.n))
+ ;; right is too big
+ (let ((r.l.n (node/size (node/l r)))
+ (r.r.n (node/size (node/r r))))
+ (if (fix:< r.l.n r.r.n)
+ (single-l k v l r)
+ (double-l k v l r))))
+ ((fix:> l.n (fix:* wt-tree-ratio r.n))
+ ;; left is too big
+ (let ((l.l.n (node/size (node/l l)))
+ (l.r.n (node/size (node/r l))))
+ (if (fix:< l.r.n l.l.n)
+ (single-r k v l r)
+ (double-r k v l r))))
+ (else
+ (simple-join)))))
+ ;;
+ ;; Node tree procedures that are independent of key<?
+ ;;
+
+ (define (node/min node)
+ (cond ((empty? node) (error:empty 'min))
+ ((empty? (node/l node)) node)
+ (else (node/min (node/l node)))))
+
+ (define (node/delmin node)
+ (cond ((empty? node) (error:empty 'delmin))
+ ((empty? (node/l node)) (node/r node))
+ (else (t-join (node/k node) (node/v node)
+ (node/delmin (node/l node)) (node/r node)))))
+
+ (define (node/concat2 node1 node2)
+ (cond ((empty? node1) node2)
+ ((empty? node2) node1)
+ (else
+ (let ((min-node (node/min node2)))
+ (t-join (node/k min-node) (node/v min-node)
+ node1 (node/delmin node2))))))
+
+ (define (node/inorder-fold procedure base node)
+ (define (fold base node)
+ (if (empty? node)
+ base
+ (with-n-node node
+ (lambda (k v l r)
+ (fold (procedure k v (fold base r)) l)))))
+ (fold base node))
+
+ (define (node/for-each procedure node)
+ (if (not (empty? node))
+ (with-n-node node
+ (lambda (k v l r)
+ (node/for-each procedure l)
+ (procedure k v)
+ (node/for-each procedure r)))))
+
+ (define (node/height node)
+ (if (empty? node)
+ 0
+ (+ 1 (max (node/height (node/l node))
+ (node/height (node/r node))))))
+
+ (define (node/index node index)
+ (define (loop node index)
+ (let ((size.l (node/size (node/l node))))
+ (cond ((fix:< index size.l) (loop (node/l node) index))
+ ((fix:> index size.l) (loop (node/r node)
+ (fix:- index (fix:+ 1 size.l))))
+ (else node))))
+ (let ((bound (node/size node)))
+ (if (or (< index 0)
+ (>= index bound)
+ (not (fix:fixnum? index)))
+ (error:bad-range-argument index 'node/index)
+ (loop node index))))
+
+ (define (error:empty owner)
+ (error "Operation requires non-empty tree:" owner))
+
+
+ (define (local:make-wt-tree-type key<?)
+
+ ;; MIT-Scheme definitions:
+ ;;(declare (integrate key<?))
+ ;;(define-integrable (key>? x y) (key<? y x))
+
+ (define (key>? x y) (key<? y x))
+
+ (define (node/find k node)
+ ;; Returns either the node or #f.
+ ;; Loop takes D comparisons where D is the depth of the tree
+ ;; rather than the traditional compare-low, compare-high which
+ ;; takes on average 1.5(D-1) comparisons
+ (define (loop this best)
+ (cond ((empty? this) best)
+ ((key<? k (node/k this)) (loop (node/l this) best))
+ (else (loop (node/r this) this))))
+ (let ((best (loop node #f)))
+ (cond ((not best) #f)
+ ((key<? (node/k best) k) #f)
+ (else best))))
+
+ (define (node/rank k node rank)
+ (cond ((empty? node) #f)
+ ((key<? k (node/k node)) (node/rank k (node/l node) rank))
+ ((key>? k (node/k node))
+ (node/rank k (node/r node)
+ (fix:+ 1 (fix:+ rank (node/size (node/l node))))))
+ (else (fix:+ rank (node/size (node/l node))))))
+
+ (define (node/add node k v)
+ (if (empty? node)
+ (node/singleton k v)
+ (with-n-node node
+ (lambda (key val l r)
+ (cond ((key<? k key) (t-join key val (node/add l k v) r))
+ ((key<? key k) (t-join key val l (node/add r k v)))
+ (else (n-join key v l r)))))))
+
+ (define (node/delete x node)
+ (if (empty? node)
+ empty
+ (with-n-node node
+ (lambda (key val l r)
+ (cond ((key<? x key) (t-join key val (node/delete x l) r))
+ ((key<? key x) (t-join key val l (node/delete x r)))
+ (else (node/concat2 l r)))))))
+
+ (define (node/concat tree1 tree2)
+ (cond ((empty? tree1) tree2)
+ ((empty? tree2) tree1)
+ (else
+ (let ((min-node (node/min tree2)))
+ (node/concat3 (node/k min-node) (node/v min-node) tree1
+ (node/delmin tree2))))))
+
+ (define (node/concat3 k v l r)
+ (cond ((empty? l) (node/add r k v))
+ ((empty? r) (node/add l k v))
+ (else
+ (let ((n1 (node/size l))
+ (n2 (node/size r)))
+ (cond ((fix:< (fix:* wt-tree-ratio n1) n2)
+ (with-n-node r
+ (lambda (k2 v2 l2 r2)
+ (t-join k2 v2 (node/concat3 k v l l2) r2))))
+ ((fix:< (fix:* wt-tree-ratio n2) n1)
+ (with-n-node l
+ (lambda (k1 v1 l1 r1)
+ (t-join k1 v1 l1 (node/concat3 k v r1 r)))))
+ (else
+ (n-join k v l r)))))))
+
+ (define (node/split-lt node x)
+ (cond ((empty? node) empty)
+ ((key<? x (node/k node))
+ (node/split-lt (node/l node) x))
+ ((key<? (node/k node) x)
+ (node/concat3 (node/k node) (node/v node) (node/l node)
+ (node/split-lt (node/r node) x)))
+ (else (node/l node))))
+
+ (define (node/split-gt node x)
+ (cond ((empty? node) empty)
+ ((key<? (node/k node) x)
+ (node/split-gt (node/r node) x))
+ ((key<? x (node/k node))
+ (node/concat3 (node/k node) (node/v node)
+ (node/split-gt (node/l node) x) (node/r node)))
+ (else (node/r node))))
+
+ (define (node/union tree1 tree2)
+ (cond ((empty? tree1) tree2)
+ ((empty? tree2) tree1)
+ (else
+ (with-n-node tree2
+ (lambda (ak av l r)
+ (let ((l1 (node/split-lt tree1 ak))
+ (r1 (node/split-gt tree1 ak)))
+ (node/concat3 ak av (node/union l1 l) (node/union r1 r))))))))
+
+ (define (node/difference tree1 tree2)
+ (cond ((empty? tree1) empty)
+ ((empty? tree2) tree1)
+ (else
+ (with-n-node tree2
+ (lambda (ak av l r)
+ (let ((l1 (node/split-lt tree1 ak))
+ (r1 (node/split-gt tree1 ak)))
+ av
+ (node/concat (node/difference l1 l)
+ (node/difference r1 r))))))))
+
+ (define (node/intersection tree1 tree2)
+ (cond ((empty? tree1) empty)
+ ((empty? tree2) empty)
+ (else
+ (with-n-node tree2
+ (lambda (ak av l r)
+ (let ((l1 (node/split-lt tree1 ak))
+ (r1 (node/split-gt tree1 ak)))
+ (if (node/find ak tree1)
+ (node/concat3 ak av (node/intersection l1 l)
+ (node/intersection r1 r))
+ (node/concat (node/intersection l1 l)
+ (node/intersection r1 r)))))))))
+
+ (define (node/subset? tree1 tree2)
+ (or (empty? tree1)
+ (and (fix:<= (node/size tree1) (node/size tree2))
+ (with-n-node tree1
+ (lambda (k v l r)
+ v
+ (cond ((key<? k (node/k tree2))
+ (and (node/subset? l (node/l tree2))
+ (node/find k tree2)
+ (node/subset? r tree2)))
+ ((key>? k (node/k tree2))
+ (and (node/subset? r (node/r tree2))
+ (node/find k tree2)
+ (node/subset? l tree2)))
+ (else
+ (and (node/subset? l (node/l tree2))
+ (node/subset? r (node/r tree2))))))))))
+
+
+ ;;; Tree interface: stripping off or injecting the tree types
+
+ (define (tree/map-add tree k v)
+ (%make-wt-tree (tree/type tree)
+ (node/add (tree/root tree) k v)))
+
+ (define (tree/insert! tree k v)
+ (set-tree/root! tree (node/add (tree/root tree) k v)))
+
+ (define (tree/delete tree k)
+ (%make-wt-tree (tree/type tree)
+ (node/delete k (tree/root tree))))
+
+ (define (tree/delete! tree k)
+ (set-tree/root! tree (node/delete k (tree/root tree))))
+
+ (define (tree/split-lt tree key)
+ (%make-wt-tree (tree/type tree)
+ (node/split-lt (tree/root tree) key)))
+
+ (define (tree/split-gt tree key)
+ (%make-wt-tree (tree/type tree)
+ (node/split-gt (tree/root tree) key)))
+
+ (define (tree/union tree1 tree2)
+ (%make-wt-tree (tree/type tree1)
+ (node/union (tree/root tree1) (tree/root tree2))))
+
+ (define (tree/intersection tree1 tree2)
+ (%make-wt-tree (tree/type tree1)
+ (node/intersection (tree/root tree1) (tree/root tree2))))
+
+ (define (tree/difference tree1 tree2)
+ (%make-wt-tree (tree/type tree1)
+ (node/difference (tree/root tree1) (tree/root tree2))))
+
+ (define (tree/subset? tree1 tree2)
+ (node/subset? (tree/root tree1) (tree/root tree2)))
+
+ (define (alist->tree alist)
+ (define (loop alist node)
+ (cond ((null? alist) node)
+ ((pair? alist) (loop (cdr alist)
+ (node/add node (caar alist) (cdar alist))))
+ (else
+ (error:wrong-type-argument alist "alist" 'alist->tree))))
+ (%make-wt-tree my-type (loop alist empty)))
+
+ (define (tree/get tree key default)
+ (let ((node (node/find key (tree/root tree))))
+ (if node
+ (node/v node)
+ default)))
+
+ (define (tree/rank tree key) (node/rank key (tree/root tree) 0))
+
+ (define (tree/member? key tree)
+ (and (node/find key (tree/root tree))
+ #t))
+
+ (define my-type #F)
+
+ (set! my-type
+ (%make-tree-type
+ key<? ; key<?
+ alist->tree ; alist->tree
+ tree/map-add ; add
+ tree/insert! ; insert!
+ tree/delete ; delete
+ tree/delete! ; delete!
+ tree/member? ; member?
+ tree/get ; lookup
+ tree/split-lt ; split-lt
+ tree/split-gt ; split-gt
+ tree/union ; union
+ tree/intersection ; intersection
+ tree/difference ; difference
+ tree/subset? ; subset?
+ tree/rank ; rank
+ ))
+
+ my-type)
+
+ (define (guarantee-tree tree procedure)
+ (if (not (wt-tree? tree))
+ (error:wrong-type-argument tree "weight-balanced tree" procedure)))
+
+ (define (guarantee-tree-type type procedure)
+ (if (not (tree-type? type))
+ (error:wrong-type-argument type "weight-balanced tree type" procedure)))
+
+ (define (guarantee-compatible-trees tree1 tree2 procedure)
+ (guarantee-tree tree1 procedure)
+ (guarantee-tree tree2 procedure)
+ (if (not (eq? (tree/type tree1) (tree/type tree2)))
+ (error "The trees" tree1 'and tree2 'have 'incompatible 'types
+ (tree/type tree1) 'and (tree/type tree2))))
+
+;;;______________________________________________________________________
+;;;
+;;; Export interface
+;;;
+ (set! make-wt-tree-type local:make-wt-tree-type)
+
+ (set! make-wt-tree
+ (lambda (tree-type)
+ (%make-wt-tree tree-type empty)))
+
+ (set! singleton-wt-tree
+ (lambda (type key value)
+ (guarantee-tree-type type 'singleton-wt-tree)
+ (%make-wt-tree type (node/singleton key value))))
+
+ (set! alist->wt-tree
+ (lambda (type alist)
+ (guarantee-tree-type type 'alist->wt-tree)
+ ((tree-type/alist->tree type) alist)))
+
+ (set! wt-tree/empty?
+ (lambda (tree)
+ (guarantee-tree tree 'wt-tree/empty?)
+ (empty? (tree/root tree))))
+
+ (set! wt-tree/size
+ (lambda (tree)
+ (guarantee-tree tree 'wt-tree/size)
+ (node/size (tree/root tree))))
+
+ (set! wt-tree/add
+ (lambda (tree key datum)
+ (guarantee-tree tree 'wt-tree/add)
+ ((tree-type/add (tree/type tree)) tree key datum)))
+
+ (set! wt-tree/delete
+ (lambda (tree key)
+ (guarantee-tree tree 'wt-tree/delete)
+ ((tree-type/delete (tree/type tree)) tree key)))
+
+ (set! wt-tree/add!
+ (lambda (tree key datum)
+ (guarantee-tree tree 'wt-tree/add!)
+ ((tree-type/insert! (tree/type tree)) tree key datum)))
+
+ (set! wt-tree/delete!
+ (lambda (tree key)
+ (guarantee-tree tree 'wt-tree/delete!)
+ ((tree-type/delete! (tree/type tree)) tree key)))
+
+ (set! wt-tree/member?
+ (lambda (key tree)
+ (guarantee-tree tree 'wt-tree/member?)
+ ((tree-type/member? (tree/type tree)) key tree)))
+
+ (set! wt-tree/lookup
+ (lambda (tree key default)
+ (guarantee-tree tree 'wt-tree/lookup)
+ ((tree-type/lookup (tree/type tree)) tree key default)))
+
+ (set! wt-tree/split<
+ (lambda (tree key)
+ (guarantee-tree tree 'wt-tree/split<)
+ ((tree-type/split-lt (tree/type tree)) tree key)))
+
+ (set! wt-tree/split>
+ (lambda (tree key)
+ (guarantee-tree tree 'wt-tree/split>)
+ ((tree-type/split-gt (tree/type tree)) tree key)))
+
+ (set! wt-tree/union
+ (lambda (tree1 tree2)
+ (guarantee-compatible-trees tree1 tree2 'wt-tree/union)
+ ((tree-type/union (tree/type tree1)) tree1 tree2)))
+
+ (set! wt-tree/intersection
+ (lambda (tree1 tree2)
+ (guarantee-compatible-trees tree1 tree2 'wt-tree/intersection)
+ ((tree-type/intersection (tree/type tree1)) tree1 tree2)))
+
+ (set! wt-tree/difference
+ (lambda (tree1 tree2)
+ (guarantee-compatible-trees tree1 tree2 'wt-tree/difference)
+ ((tree-type/difference (tree/type tree1)) tree1 tree2)))
+
+ (set! wt-tree/subset?
+ (lambda (tree1 tree2)
+ (guarantee-compatible-trees tree1 tree2 'wt-tree/subset?)
+ ((tree-type/subset? (tree/type tree1)) tree1 tree2)))
+
+ (set! wt-tree/set-equal?
+ (lambda (tree1 tree2)
+ (and (wt-tree/subset? tree1 tree2)
+ (wt-tree/subset? tree2 tree1))))
+
+ (set! wt-tree/fold
+ (lambda (combiner-key-datum-result init tree)
+ (guarantee-tree tree 'wt-tree/fold)
+ (node/inorder-fold combiner-key-datum-result
+ init
+ (tree/root tree))))
+
+ (set! wt-tree/for-each
+ (lambda (action-key-datum tree)
+ (guarantee-tree tree 'wt-tree/for-each)
+ (node/for-each action-key-datum (tree/root tree))))
+
+ (set! wt-tree/index
+ (lambda (tree index)
+ (guarantee-tree tree 'wt-tree/index)
+ (let ((node (node/index (tree/root tree) index)))
+ (and node (node/k node)))))
+
+ (set! wt-tree/index-datum
+ (lambda (tree index)
+ (guarantee-tree tree 'wt-tree/index-datum)
+ (let ((node (node/index (tree/root tree) index)))
+ (and node (node/v node)))))
+
+ (set! wt-tree/index-pair
+ (lambda (tree index)
+ (guarantee-tree tree 'wt-tree/index-pair)
+ (let ((node (node/index (tree/root tree) index)))
+ (and node (cons (node/k node) (node/v node))))))
+
+ (set! wt-tree/rank
+ (lambda (tree key)
+ (guarantee-tree tree 'wt-tree/rank)
+ ((tree-type/rank (tree/type tree)) tree key)))
+
+ (set! wt-tree/min
+ (lambda (tree)
+ (guarantee-tree tree 'wt-tree/min)
+ (node/k (node/min (tree/root tree)))))
+
+ (set! wt-tree/min-datum
+ (lambda (tree)
+ (guarantee-tree tree 'wt-tree/min-datum)
+ (node/v (node/min (tree/root tree)))))
+
+ (set! wt-tree/min-pair
+ (lambda (tree)
+ (guarantee-tree tree 'wt-tree/min-pair)
+ (let ((node (node/min (tree/root tree))))
+ (cons (node/k node) (node/v node)))))
+
+ (set! wt-tree/delete-min
+ (lambda (tree)
+ (guarantee-tree tree 'wt-tree/delete-min)
+ (%make-wt-tree (tree/type tree)
+ (node/delmin (tree/root tree)))))
+
+ (set! wt-tree/delete-min!
+ (lambda (tree)
+ (guarantee-tree tree 'wt-tree/delete-min!)
+ (set-tree/root! tree (node/delmin (tree/root tree)))))
+
+ ;; < is a lexpr. Many compilers can open-code < so the lambda is faster
+ ;; than passing <.
+ (set! number-wt-type (local:make-wt-tree-type (lambda (u v) (< u v))))
+ (set! string-wt-type (local:make-wt-tree-type string<?))
+
+ 'done)
+\f
+;;______________________________________________________________________________
+;;
+;; Test code, using maps from digit strings to the numbers they represent.
+;;
+;; (load-option 'wt-tree)
+
+;;#|
+(define (test n)
+
+ (define (make-map lo hi step)
+ (let loop ((i lo) (map (make-wt-tree number-wt-type)))
+ (if (> i hi)
+ map
+ (loop (+ i step) (wt-tree/add map i i)))))
+
+ (define (wt-tree->alist t)
+ (wt-tree/fold (lambda (key datum rest) (cons (cons key datum) rest)) '() t))
+
+ (let loop ((numbers (make-map 2 n 1))
+ (primes (make-wt-tree number-wt-type)))
+ (if (wt-tree/empty? numbers)
+ (wt-tree/fold (lambda (key datum rest) (cons key rest)) '() primes)
+ (let ((new-prime (wt-tree/min numbers)))
+ (wt-tree/add! primes new-prime #T)
+ (loop (wt-tree/difference numbers
+ (make-map new-prime n new-prime))
+ (wt-tree/add primes new-prime #T))))))
+
+
+(lambda ()
+ (test 2000))
+
+\f
+;;; Local Variables:
+;;; eval: (put 'with-n-node 'scheme-indent-function 1)
+;;; eval: (put 'with-n-node 'scheme-indent-hook 1)
+;;; End:
\ No newline at end of file
projects / mit-scheme.git / commitdiff