Improved error message:

when argument out of range, name the term

src/frontend/evaluate.c

@@ -70,8 +70,12 @@ ft_evaluate(struct pnode *node)
         d = NULL;
     }
 
-    if (d == NULL)
+    if (d == NULL) {
+        if (node && node->pn_name) {
+            fprintf(stderr, "  in term: %s\n\n", node->pn_name);
+        }
         return NULL;
+    }
 
     if (node->pn_name && !ft_evdb && d && !d->v_link2) {
         if (d->v_name)