Start reimplementing missing ldict through bst.

doc/d-utils.md

@@ -562,6 +562,15 @@ Functional update with optional default value (defaults to #f).
 Returns a BST with only KV pairs matching the predicate which must
 accept two arguments.
 
+### bst-reduce [procedure]
+
+    (bst-reduce bst
+                proc
+                init)
+
+Like generic reduce, the proc gets accumulator, key and value
+arguments.
+
 ## util-bst-bdict [module]
 
     (import util-bst-bdict)

src/util-bst-ldict.scm

@@ -45,4 +45,7 @@
  (define (ldict-filter pred? ld)
    (bst-filter ld pred?))
 
+ (define (ldict-reduce init proc ld)
+   (bst-reduce ld proc init))
+
  )

src/util-bst.scm

@@ -36,6 +36,7 @@
   bst-update
 
   bst-filter
+  bst-reduce
 
   util-bst-tests!
   )
@@ -385,6 +386,15 @@ accept two arguments.")
 	  (cons (apply vector (bst-filter-pairs bst pred?))
 		(cddr bst)))))
 
+ (define/doc (bst-reduce bst proc init)
+   ("Like generic reduce, the proc gets accumulator, key and value
+arguments.")
+   (let ((acc init))
+     (bst-iter-kv bst
+		  (lambda (kv)
+		    (set! acc (proc acc (car kv) (cdr kv)))))
+     acc))
+
  ;; Module self-tests
  (define (util-bst-tests!)
    (run-tests