Implement ldict-empty? predicate.

src/util-dict.scm

@@ -31,6 +31,8 @@
   TAG-LDICT
   
   make-ldict
+
+  ldict-empty?
   
   ldict-has-key?
   ldict-ref
@@ -71,6 +73,15 @@
 	   (loop (ldict-set ld (caar pairs) (cdar pairs))
 		 (cdr pairs))))))
 
+ ;; Convenience accessors
+ (define ldict-meta cadr)
+ (define ldict-equality? caadr)
+ (define ldict-list cddr)
+
+ ;; Returns true if given dictionary contains no keys
+ (define (ldict-empty? d)
+   (null? (ldict-list d)))
+
  ;; Checks whether given dictionary d contains the key k.
  (define (dict-has-key? d k)
    (if (assq k d) #t #f))