Implement ldict-empty? predicate.

doc/utils.md

@@ -49,6 +49,12 @@ populating it with initial data.
 If only one argument is given, the procedure checks whether it is a
 list of equality procedure and acts accordingly.
 
+    (ldict-empty? d)
+
+* ```d``` - a ldict instance
+
+Returns true if given dictionary contains no keys.
+
 ### IO
 
     (import util-io)

src/util-dict.scm

@@ -32,6 +32,8 @@
   
   make-ldict
 
+  ldict-empty?
+  
   ldict-has-key?
   ldict-ref
   ldict-remove
@@ -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))