From 19c40c18a6a73eadb1bb19f2a2e474516de939a8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Dominik=20Pant=C5=AF=C4=8Dek?=
 <dominik.pantucek@trustica.cz>
Date: Fri, 7 Jul 2023 09:53:45 +0200
Subject: [PATCH] Finding and filtering pairs.

---
 src/util-bst.scm | 27 +++++++++++++++++++++++----
 1 file changed, 23 insertions(+), 4 deletions(-)

diff --git a/src/util-bst.scm b/src/util-bst.scm
index 8ad2d57..3d67f74 100644
--- a/src/util-bst.scm
+++ b/src/util-bst.scm
@@ -26,8 +26,8 @@
   
   bst-balance
 
-  ;; bst-find-pair
-  ;; bst-filter-pairs
+  bst-find-pair
+  bst-filter-pairs
 
   ;; bst-map-list
   ;; bst-map-dict
@@ -240,8 +240,8 @@
    ("Returns all the keys contained in given dictionary.")
    (let ((res '()))
      (bst-iter-kv bst
-		  (lambda (k v)
-		    (set! res (cons k res))))
+		  (lambda (kv)
+		    (set! res (cons (car kv) res))))
      (reverse res)))
 
  ;; Converts BST to KVV
@@ -295,6 +295,25 @@
    (kvv->bst
     (bst->kvv bst)))
 
+ (define/doc (bst-find-pair bst pred?)
+   ("Finds pair by predicate that accepts both key and value.")
+   (call/cc
+    (lambda (cc)
+      (bst-iter-kv bst
+		   (lambda (kv)
+		     (when (pred? (car kv) (cdr kv))
+		       (cc kv))))
+      #f)))
+
+ (define/doc (bst-filter-pairs bst pred?)
+   ("Returns a list of key-value pairs matching predicate.")
+   (let ((res '()))
+     (bst-iter-kv bst
+		  (lambda (kv)
+		    (when (pred? (car kv) (cdr kv))
+		      (set! res (cons kv res)))))
+     res))
+
  ;; Module self-tests
  (define (util-bst-tests!)
    (run-tests