This commit is contained in:
Peter McGoron 2024-08-29 22:24:33 -04:00
parent 1b56759726
commit f160ecaae1
5 changed files with 436 additions and 6 deletions

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@ -174,7 +174,7 @@
(dl:set-head! ctr next)
#f)
(if was-tail?
(dl:set-tail! ctr tail)
(dl:set-tail! ctr prev)
#f))))
;;; (DL:PUSH-LIST-BACK CTR LST) appends LST to CTR.

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@ -114,3 +114,63 @@
(if (< (char->integer x) (char->integer y))
'<
'>))))))
(define max
(lambda (curmax . rest)
(if (null? rest)
curmax
(let ((next-num (car rest)))
(apply max
(cons (if (> next-num curmax) next-num curmax)
(cdr rest)))))))
(define all
(lambda (f l)
(cond
((null? l) #t)
((not (f (car l))) (all f (cdr l)))
(else #f))))
(define any
(lambda (f l)
(cond
((null? l) #f)
((f (car l)) #t)
(else (any f (cdr l))))))
(macro
cond-expand
(lambda (body)
(letrec
((loop
(lambda (body)
(if (null? body)
#f
(let ((elem (car body)))
(cond
((eqv? (car elem) 'else)
(cons 'begin (cdr elem)))
((and (pair? elem)
(passes? (car elem)))
(cons 'begin (cdr elem)))
(else (loop (cdr body))))))))
(passes?
(lambda (boolean-form)
(cond
((eqv? boolean-form 'miniscm-unslisp) #t)
((eqv? boolean-form 'r3rs) #t)
((symbol? boolean-form) #f)
((not (pair? boolean-form)) (error "invalid boolean form"))
((eqv? (car boolean-form) 'and)
(all passes? (cdr boolean-form)))
((eqv? (car boolean-form) 'or)
(any passes? (cdr boolean-form)))
((eqv? (car boolean-form) 'not)
(not (passes? (cadr boolean-form))))
(else (error "invalid boolean function"))))))
(loop (cdr body)))))
(define (abs x)
(if (< x 0)
(- x)
x))

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@ -79,7 +79,6 @@
* Define or undefine following symbols as you need.
*/
/* #define VERBOSE */ /* define this if you want verbose GC */
#define VERBOSE
#define AVOID_HACK_LOOP /* define this if your compiler is poor
* enougth to complain "do { } while (0)"
* construction.
@ -91,6 +90,8 @@
#define USE_MACRO /* undef this if you do not need macro */
#endif
#define USE_MACRO
#ifdef USE_QQUOTE
/*--
* If your machine can't support "forward single quotation character"

357
set.scm Normal file
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@ -0,0 +1,357 @@
;;; Copyright (C) Peter McGoron 2024
;;; This program is free software: you can redistribute it and/or modify
;;; it under the terms of the GNU General Public License as published by
;;; the Free Software Foundation, version 3 of the License.
;;;
;;; This program is distributed in the hope that it will be useful,
;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;;; GNU General Public License for more details.
;;;
;;; You should have received a copy of the GNU General Public License
;;; along with this program. If not, see <https://www.gnu.org/licenses/>.
;;; Persistent AVL sets and maps using JOIN.
;;; ;;;;;;;;;;;;;;;;
;;; Nodes, direction
;;; ;;;;;;;;;;;;;;;;
;;; Returns the slot number for
;;; =: The node data
;;; h: the height
;;; <: the left child
;;; >: the right child
(define %set:accessor
(lambda (sym)
(cond
((eq? sym '=) 0)
((eq? sym 'h) 1)
((eq? sym '<) 2)
((eq? sym '>) 3)
(else (error "invalid direction")))))
;;; Gets data from node value given accessor symbol.
(define %set:get
(lambda (t sym)
(vector-ref t (%set:accessor sym))))
(define %set->sexpr
(lambda (node)
(if (null? node)
'()
(list (list 'data (%set:get node '=))
(list '< (%set->sexpr (%set:get node '<)))
(list '> (%set->sexpr (%set:get node '>)))))))
;;; Get the height of a node, handling the empty node.
(define %set:height
(lambda (node)
(if (null? node)
0
(%set:get node 'h))))
;;; Get the difference between the heights of two trees.
(define %set:height-diff
(lambda (t1 t2)
(- (%set:height t1) (%set:height t2))))
;;; Get the balance factor of a tree.
(define %set:bal
(lambda (t) (%set:height-diff (%set:get t '<)
(%set:get t '>))))
;;; Set data in node given accessor symbol.
(define %set:set!
(lambda (node dir x)
(vector-set! node (%set:accessor dir) x)))
;;; Construct a new tree with data VAL.
(define %set:node
(lambda (val dir1 node1 dir2 node2)
(let ((node (vector val (+ 1
(max (%set:height node1)
(%set:height node2)))
'() '())))
(%set:set! node dir1 node1)
(%set:set! node dir2 node2)
node)))
(define %set:invdir
(lambda (dir)
(cond
((eq? dir '<) '>)
((eq? dir '>) '<)
(else (error "invalid direction")))))
;;; ;;;;;;;;;;;;;;
;;; Tree rotations
;;; ;;;;;;;;;;;;;;
;;; Rotate NODE to the left (dir = '>) or right (dir = '<).
(define %set:rotate
(lambda (node dir)
(if (null? node)
#f
(let ((invdir (%set:invdir dir)))
(let ((child (%set:get node invdir)))
(let ((to-swap (%set:get child dir)))
(%set:node (%set:get child '=)
dir (%set:node (%set:get node '=)
dir (%set:get node dir)
invdir to-swap)
invdir (%set:get child invdir))))))))
;;; ;;;;;;;;;;;;;;;;;;;
;;; JOIN function for AVL trees.
;;; ;;;;;;;;;;;;;;;;;;;
;;; Handles rebalancing of the tree.
(define %set:join
(lambda (heavier val lighter heavier-dir)
(let ((heavy-val (%set:get heavier '=))
(lighter-dir (%set:invdir heavier-dir)))
(let ((heavy-heavy (%set:get heavier heavier-dir))
(heavy-light (%set:get heavier lighter-dir)))
(if (<= (abs (%avl:diff heavy-light lighter) 1))
(let ((node (%set:node val
heavier-dir heavy-light
lighter-dir lighter)))
(if (<= (abs (%set:bal node)) 1)
(%set:node heavy-val
heavier-dir heavy-heavy
lighter-dir node)
(%set:rotate (%set:node heavy-val
heavier-dir heavy-heavy
lighter-dir
(%set:rotate node lighter-dir))
heavier-dir)))
(let ((new-light (%set:join heavy-light val lighter heavier-dir)))
(let ((node (%set:node heavy-val
heavier-dir heavy-heavy
lighter-dir new-light)))
(if (<= (abs (%set:bal node)) 1)
node
(%set:rotate node heavier-dir)))))))))
;;; JOIN takes two trees and the data for a node, such that all nodes
;;; in LEFT are less than or equal to VAL, and all nodes in RIGHT are
;;; greater than or equal to VAL, and outputs a balanced binary search
;;; tree.
(define set:join
(lambda (left val right)
(let ((diff (%set:diff left right)))
(cond
((> diff 1) (%set:join left val right '<))
((< diff -1) (%set:join right val left '>))
(else (set:node val '< left '> right))))))
(define set:join2
(letrec
((join2
(lambda (left right)
(if (null? left)
right
(let ((split-last-tree (split-last left)))
(set:join (bst:get split-last-tree '<)
(bst:get split-last-tree '=)
right)))))
(split-last
(lambda (tree)
(let ((right (set:get tree '>)))
(if (null? right)
tree
(let ((last (split-last right)))
(bst:node (set:get last '=)
(join (set:get tree '<)
(set:get tree '=)
(set:get last '<))
'())))))))
join2))
;;; ;;;;;;;;;;;;;;;;;
;;; Element functions
;;; ;;;;;;;;;;;;;;;;;
;;; (SET:IN <=>) generates a search function for comparison function <=>.
;;; (SEARCH TREE DATA) searches TREE for a node that matches DATA.
;;; It will return the node that contains the matched DATA, or #F.
(define set:in
(lambda (<=>)
(lambda (tree data)
(letrec
((loop
(lambda (tree)
(if (null? tree)
#f
(let ((dir (<=> (%set:get tree '=) data)))
(if (eq? dir '=)
tree
(loop (set:get tree dir))))))))
(loop tree)))))
;;; (SET:INSERT <=>) generates an insert function for comparison function
;;; <=>.
;;; (INSERT TREE NODE) inserts NODE into TREE. It returns
;;; (CONS NEWTREE FOUND), where FOUND is the node that was replaced by
;;; NODE, and #F otherwise, and NEWTREE is the new root of the tree.
(define set:insert
(lambda (<=>)
(lambda (tree node)
(let ((found #f))
(letrec
((loop
(lambda (tree)
(if (null? tree)
node
(let ((dir (<=> (%set:get tree '=)
(%set:get node '=)))
(left (%set:get tree '<))
(right (%set:get tree '>)))
(if (eq? dir '=)
(begin
(set! found tree)
(set:node (set:get node '=)
'< left '> right))
(join (set:node (%set:get tree '=)
dir (loop left)
(set:invdir dir) right))))))))
(let ((newtree (loop tree)))
(cons newtree found)))))))
;;; (SET:DELETE <=>) generates a delete function for comparison function
;;; <=>.
;;; (DELETE TREE DATA) deletes a node from TREE that compares equal to
;;; DATA. The function returns (CONS NEWTREE FOUND), where FOUND is the
;;; deleted node, or #F if not found, and NEWTREE is the root of the new
;;; tree.
(define set:delete
(lambda (<=>)
(lambda (tree node)
(let ((found #f))
(letrec
((loop
(lambda (tree)
(if (null? tree)
node
(let ((dir (<=> (%set:get tree '=)
(%set:get node '=)))
(left (%set:get tree '<))
(right (%set:get tree '>)))
(if (eq? dir '=)
(begin
(set! found tree)
(set:join2 left right))
(join (set:node (%set:get tree '=)
dir (loop left)
(set:invdir dir) right))))))))
(let ((newtree (loop tree)))
(cons newtree found)))))))
;;; ;;;;;;;;;;;
;;; For strings
;;; ;;;;;;;;;;;
(cond-expand
((not miniscm-unslisp)
(define (string<=> x y)
(cond
((string<? x y) '<)
((string>? x y) '>)
(else '=)))))
(define map:string<=>
(lambda (x y)
(string<=> (car x) (car y))))
(define %smap:insert (set:insert map:string<=>))
(define smap:insert
(lambda (tree key val)
(%smap:insert tree (%set:node (cons key val)
'< '()
'> '()))))
(define %smap:search (set:in map:string<=>))
(define smap:search
(lambda (tree key)
(%smap:search tree (cons key '()))))
(define %smap:delete (set:delete map:string<=>))
(define smap:delete
(lambda (tree key)
(%smap:delete tree (%set:node (cons key '())
'< '() '> '()))))
(define smap:key
(lambda (node) (car (%set:get node '=))))
(define smap:val
(lambda (node) (cdr (%set:get node '=))))
(define %set:tests
(list
(cons "rotate right"
(lambda ()
(let ((right (%set:rotate (%set:node 1
'< (%set:node 2
'< (%set:node 3
'< '()
'> '())
'> (%set:node 4
'< '()
'> '()))
'> (%set:node 5 '< '() '> '()))
'>)))
(cond
((not (eqv? (%set:get right '=) 2)) "bad parent")
((not (eqv? (%set:get (%set:get right '>) '=) 1)) "bad right child")
((not (eqv? (%set:get (%set:get right '<) '=) 3)) "bad left child")
((not (eqv? (%set:get (%set:get (%set:get right '>) '>) '=) 5))
"bad right child of right child")
((not (eqv? (%set:get (%set:get (%set:get right '>) '<) '=) 4))
"bad left child of right child")
(else #t)))))
(cons "rotate left"
(lambda ()
(let ((right (%set:rotate (%set:node 1
'> (%set:node 2
'< (%set:node 3
'< '()
'> '())
'> (%set:node 4
'< '()
'> '()))
'< (%set:node 5 '< '() '> '()))
'<)))
(cond
((not (eqv? (%set:get right '=) 2)) "bad parent")
((not (eqv? (%set:get (%set:get right '>) '=) 4)) "bad right child")
((not (eqv? (%set:get (%set:get right '<) '=) 1)) "bad left child")
((not (eqv? (%set:get (%set:get (%set:get right '<) '>) '=) 3))
"bad right child of left child")
((not (eqv? (%set:get (%set:get (%set:get right '<) '<) '=) 5))
"bad left child of left child")
(else #t)))))
(cons "insert then delete"
(lambda ()
(let ((insert-return (smap:insert '() (string #\a) 5)))
(cond
((not (pair? insert-return)) "invalid insert return")
((cdr insert-return) "string found in empty tree")
(else
(let ((tree (car insert-return)))
(let ((found (smap:search tree (string #\a))))
(cond
((not found) "string not in tree")
((not (equal? (smap:key tree) (string #\a)))
"returned key not equal to a")
((not (equal? (smap:val tree) 5))
"returned value not equal to 5")
(else
(let ((delete-return (smap:delete tree (string #\a))))
(cond
((not (pair? delete-return))
"invalid delete return")
((not (cdr delete-return)) "string not found")
((not (eqv? (car delete-return) '()))
"returned tree not null")
(else #t))))))))))))))

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@ -48,10 +48,22 @@
(loop (cdr rest)))))))))
(loop tests))))
(define report-tests
(lambda (tests)
(let ((res (run-tests tests)))
(if (eq? res #t)
(display "passed")
(begin
(display "failed: ")
(display res))))
(newline)))
(load "doubly-linked-list.scm")
(display "running doubly linked list tests")
(display "running doubly linked list tests: ")
(newline)
(if (run-tests %dl:tests)
(display "doubly linked list tests: passed")
(display "doubly linked list tests: failed"))
(report-tests %dl:tests)
(load "set.scm")
(display "running string BST-AVL tests")
(newline)
(report-tests %set:tests)