Validation for empty objects

Now (correctly) fails to parse {,}

c/jv.c

@@ -632,6 +632,15 @@ static int jvp_object_delete(jv_complex* object, jvp_string* key) {
   return 0;
 }
 
+static int jvp_object_length(jv_complex* object) {
+  int n = 0;
+  for (int i=0; i<jvp_object_size(object); i++) {
+    struct object_slot* slot = jvp_object_get_slot(object, i);
+    if (slot->string) n++;
+  }
+  return n;
+}
+
 /*
  * Objects (public interface)
  */
@@ -670,6 +679,13 @@ jv jv_object_delete(jv object, jv key) {
   return object;
 }
 
+int jv_object_length(jv object) {
+  assert(jv_get_kind(object) == JV_KIND_OBJECT);
+  int n = jvp_object_length(&object.val.complex);
+  jv_free(object);
+  return n;
+}
+
 /*
  * Object iteration (internal helpers)
  */

c/jv.h

@@ -109,6 +109,7 @@ jv jv_object();
 jv jv_object_get(jv object, jv key);
 jv jv_object_set(jv object, jv key, jv value);
 jv jv_object_delete(jv object, jv key);
+int jv_object_length(jv object);
 
 int jv_object_iter(jv);
 int jv_object_iter_next(jv, int);

c/jv_parse.c

@@ -100,7 +100,8 @@ pfunc token(char ch) {
     } else {
       if (jv_get_kind(stack[stackpos-1]) != JV_KIND_OBJECT)
         return "Unmatched '}'";
-      // FIXME: assert object empty
+      if (jv_object_length(jv_copy(stack[stackpos-1])) != 0)
+        return "Expected another key-value pair";
     }
     hasnext = 1;
     next = stack[--stackpos];