diff --git a/library/itries.yap b/library/itries.yap
index 323dc2daa..c7b3618d3 100644
--- a/library/itries.yap
+++ b/library/itries.yap
@@ -28,13 +28,12 @@
 		  itrie_save/2,
 		  itrie_save_as_trie/2,
 		  itrie_load/2,
+		  itrie_save2stream/2,
+		  itrie_loadFromstream/2,
 		  itrie_stats/4,
 		  itrie_max_stats/4,
 		  itrie_usage/4,
-		  itrie_print/1,
-		  %added by nf
-		  itrie_save2stream/2,
-		  itrie_loadFromstream/2
+		  itrie_print/1
           ]).
 
 :- load_foreign_files([itries], [], init_itries).
diff --git a/library/tries/base_tries.c b/library/tries/base_tries.c
index 7a53f2e43..115dd5ec9 100644
--- a/library/tries/base_tries.c
+++ b/library/tries/base_tries.c
@@ -72,8 +72,10 @@ void trie_data_destruct(TrNode node) {
   if (TrData_next(data)) {
     TrData_previous(TrData_next(data)) = TrData_previous(data);
     TrData_next(TrData_previous(data)) = TrData_next(data);
-  } else
+  } else {
+    TrEntry_last_data(trie) = TrData_previous(data);
     TrData_next(TrData_previous(data)) = NULL;
+  }
   free_trie_data(data);
   return;
 }
@@ -177,6 +179,8 @@ TrData trie_get_last_entry(TrEntry trie) {
   TrData data;
   
   data = TrEntry_last_data(trie);
+  if (data == AS_TR_DATA_NEXT(&TrEntry_first_data(trie)))
+    return NULL;
   return data;
 }
 
diff --git a/library/tries/base_tries.h b/library/tries/base_tries.h
index 09e6a0bee..e8c7a8788 100644
--- a/library/tries/base_tries.h
+++ b/library/tries/base_tries.h
@@ -53,32 +53,32 @@ typedef struct trie_data {
 /*           Macros            */
 /* --------------------------- */
 
-#define new_trie_entry(TR_ENTRY, TR_NODE)                                              \
-        { new_struct(TR_ENTRY, TYPE_TR_ENTRY, SIZEOF_TR_ENTRY);                        \
-          TrEntry_trie(TR_ENTRY) = TR_NODE;                                            \
-          TrEntry_first_data(TR_ENTRY) = NULL;                                         \
-          TrEntry_last_data(TR_ENTRY) = NULL;                                          \
-          TrEntry_traverse_data(TR_ENTRY) = NULL;                                      \
-          TrEntry_next(TR_ENTRY) = FIRST_TRIE;                                         \
-          TrEntry_previous(TR_ENTRY) = AS_TR_ENTRY_NEXT(&FIRST_TRIE);                  \
-          INCREMENT_MEMORY(TRIE_ENGINE, SIZEOF_TR_ENTRY);                              \
+#define new_trie_entry(TR_ENTRY, TR_NODE)                                                \
+        { new_struct(TR_ENTRY, TYPE_TR_ENTRY, SIZEOF_TR_ENTRY);                          \
+          TrEntry_trie(TR_ENTRY) = TR_NODE;                                              \
+          TrEntry_first_data(TR_ENTRY) = NULL;                                           \
+          TrEntry_last_data(TR_ENTRY) = AS_TR_DATA_NEXT(&TrEntry_first_data(TR_ENTRY));  \
+          TrEntry_traverse_data(TR_ENTRY) = NULL;                                        \
+          TrEntry_next(TR_ENTRY) = FIRST_TRIE;                                           \
+          TrEntry_previous(TR_ENTRY) = AS_TR_ENTRY_NEXT(&FIRST_TRIE);                    \
+          INCREMENT_MEMORY(TRIE_ENGINE, SIZEOF_TR_ENTRY);                                \
 	}
-#define new_trie_data(TR_DATA, TR_ENTRY, TR_NODE)                                      \
-        { TrData last_data = TrEntry_last_data(TR_ENTRY);                              \
-          new_struct(TR_DATA, TYPE_TR_DATA, SIZEOF_TR_DATA);                           \
-          TrData_trie(TR_DATA) = TR_ENTRY;                                             \
-          TrData_leaf(TR_DATA) = TR_NODE;                                              \
-          TrData_next(TR_DATA) = NULL;                                                 \
-          if (last_data) {                                                             \
-            TrData_next(last_data) = TR_DATA;	         	                       \
-            TrData_previous(TR_DATA) = last_data;		                       \
-            TrEntry_last_data(TR_ENTRY) = TR_DATA;                                     \
-          } else { 	                                                               \
-            TrData_previous(TR_DATA) = AS_TR_DATA_NEXT(&TrEntry_first_data(TR_ENTRY)); \
-            TrEntry_first_data(TR_ENTRY) = TR_DATA;                                    \
-            TrEntry_last_data(TR_ENTRY) = TR_DATA;                                     \
-          }                                                                            \
-          INCREMENT_MEMORY(TRIE_ENGINE, SIZEOF_TR_DATA);                               \
+#define new_trie_data(TR_DATA, TR_ENTRY, TR_NODE)                                        \
+        { TrData first_data = TrEntry_first_data(TR_ENTRY);                              \
+          new_struct(TR_DATA, TYPE_TR_DATA, SIZEOF_TR_DATA);                             \
+          TrData_trie(TR_DATA) = TR_ENTRY;                                               \
+          TrData_leaf(TR_DATA) = TR_NODE;                                                \
+          TrData_next(TR_DATA) = NULL;                                                   \
+          if (first_data) {                                                              \
+            TrData last_data = TrEntry_last_data(TR_ENTRY);                              \
+            TrData_next(last_data) = TR_DATA;	         	                         \
+            TrData_previous(TR_DATA) = last_data;		                         \
+          } else { 	                                                                 \
+            TrData_previous(TR_DATA) = AS_TR_DATA_NEXT(&TrEntry_first_data(TR_ENTRY));   \
+            TrEntry_first_data(TR_ENTRY) = TR_DATA;                                      \
+          }                                                                              \
+          TrEntry_last_data(TR_ENTRY) = TR_DATA;                                         \
+          INCREMENT_MEMORY(TRIE_ENGINE, SIZEOF_TR_DATA);                                 \
         } 
 
 
diff --git a/library/tries/core_tries.c b/library/tries/core_tries.c
index 424a5f40c..316b8558c 100644
--- a/library/tries/core_tries.c
+++ b/library/tries/core_tries.c
@@ -431,7 +431,8 @@ TrNode core_trie_load(TrEngine engine, FILE *file, void (*load_function)(TrNode,
   fpos_t curpos;
 
   fscanf(file, "%14s", version);
-  if (fgetpos(file, &curpos) ) return NULL;
+  if (fgetpos(file, &curpos))
+    return NULL;
 
   if (!strcmp(version, "BEGIN_TRIE_v2")) {
     fseek(file, -11, SEEK_END);
@@ -442,7 +443,8 @@ TrNode core_trie_load(TrEngine engine, FILE *file, void (*load_function)(TrNode,
       fprintf(stderr, "******************************************\n");  
       return NULL;
     }
-    if (fsetpos(file, &curpos) ) return NULL;
+    if (fsetpos(file, &curpos))
+      return NULL;
     CURRENT_LOAD_VERSION = 2;
   } else if (!strcmp(version, "BEGIN_TRIE")) {
     fseek(file, -8, SEEK_END);
@@ -453,7 +455,8 @@ TrNode core_trie_load(TrEngine engine, FILE *file, void (*load_function)(TrNode,
       fprintf(stderr, "******************************************\n");  
       return NULL;
     }
-    if (fsetpos(file, &curpos) )  return NULL;
+    if (fsetpos(file, &curpos))
+      return NULL;
     CURRENT_LOAD_VERSION = 1;
   } else {
     fprintf(stderr, "****************************************\n");
diff --git a/library/tries/itries.c b/library/tries/itries.c
index 5a1b66e9e..ef527a557 100644
--- a/library/tries/itries.c
+++ b/library/tries/itries.c
@@ -47,13 +47,13 @@ static int p_itrie_count_intersect(void);
 static int p_itrie_save(void);
 static int p_itrie_save_as_trie(void);
 static int p_itrie_load(void);
+static int p_itrie_save2stream(void);
+static int p_itrie_loadFromStream(void);
 static int p_itrie_stats(void);
 static int p_itrie_max_stats(void);
 static int p_itrie_usage(void);
 static int p_itrie_print(void);
-//nf
-static int p_itrie_loadFromStream(void);
-static int p_itrie_save2stream(void);
+
 
 
 /* -------------------------- */
@@ -85,13 +85,12 @@ void init_itries(void) {
   YAP_UserCPredicate("itrie_save", p_itrie_save, 2);
   YAP_UserCPredicate("itrie_save_as_trie", p_itrie_save_as_trie, 2);
   YAP_UserCPredicate("itrie_load", p_itrie_load, 2);
+  YAP_UserCPredicate("itrie_save2stream", p_itrie_save2stream, 2);
+  YAP_UserCPredicate("itrie_loadFromstream", p_itrie_loadFromStream, 2);
   YAP_UserCPredicate("itrie_stats", p_itrie_stats, 4);
   YAP_UserCPredicate("itrie_max_stats", p_itrie_max_stats, 4);
   YAP_UserCPredicate("itrie_usage", p_itrie_usage, 4);
   YAP_UserCPredicate("itrie_print", p_itrie_print, 1);
-  // nf
-  YAP_UserCPredicate("itrie_save2stream", p_itrie_save2stream, 2);
-  YAP_UserCPredicate("itrie_loadFromstream", p_itrie_loadFromStream, 2);
   return;
 }
 
@@ -101,7 +100,7 @@ void init_itries(void) {
 /*      Local Procedures      */
 /* -------------------------- */
 
-/* itrie_open(+Itrie) */
+/* itrie_open(-Itrie) */
 #define arg_itrie YAP_ARG1
 static int p_itrie_open(void) {
   TrEntry itrie;
@@ -117,7 +116,7 @@ static int p_itrie_open(void) {
 #undef arg_itrie
 
 
-/* itrie_close(-Itrie) */
+/* itrie_close(+Itrie) */
 #define arg_itrie YAP_ARG1
 static int p_itrie_close(void) {
   /* check arg */
@@ -138,7 +137,7 @@ static int p_itrie_close_all(void) {
 }
 
 
-/* itrie_mode(-Itrie,?Mode) */
+/* itrie_mode(+Itrie,?Mode) */
 #define arg_itrie YAP_ARG1
 #define arg_mode  YAP_ARG2
 static int p_itrie_mode(void) {
@@ -189,7 +188,7 @@ static int p_itrie_mode(void) {
 #undef arg_mode
 
 
-/* itrie_timestamp(-Itrie,?Time) */
+/* itrie_timestamp(+Itrie,?Time) */
 #define arg_itrie YAP_ARG1
 #define arg_time  YAP_ARG2
 static int p_itrie_timestamp(void) {
@@ -218,7 +217,7 @@ static int p_itrie_timestamp(void) {
 #undef arg_time
 
 
-/* itrie_put_entry(-Itrie,-Entry) */
+/* itrie_put_entry(+Itrie,+Entry) */
 #define arg_itrie YAP_ARG1
 #define arg_entry YAP_ARG2
 static int p_itrie_put_entry(void) {
@@ -234,7 +233,7 @@ static int p_itrie_put_entry(void) {
 #undef arg_entry
 
 
-/* itrie_update_entry(-Itrie,-Entry) */
+/* itrie_update_entry(+Itrie,+Entry) */
 #define arg_itrie YAP_ARG1
 #define arg_entry YAP_ARG2
 static int p_itrie_update_entry(void) {
@@ -250,7 +249,7 @@ static int p_itrie_update_entry(void) {
 #undef arg_entry
 
 
-/* itrie_check_entry(-Itrie,-Entry,+Ref) */
+/* itrie_check_entry(+Itrie,+Entry,-Ref) */
 #define arg_itrie YAP_ARG1
 #define arg_entry YAP_ARG2
 #define arg_ref   YAP_ARG3
@@ -271,7 +270,7 @@ static int p_itrie_check_entry(void) {
 #undef arg_ref
 
 
-/* itrie_get_entry(-Ref,+Entry) */
+/* itrie_get_entry(+Ref,-Entry) */
 #define arg_ref   YAP_ARG1
 #define arg_entry YAP_ARG2
 static int p_itrie_get_entry(void) {
@@ -289,7 +288,7 @@ static int p_itrie_get_entry(void) {
 #undef arg_entry
 
 
-/* itrie_get_data(-Ref,+Data) */
+/* itrie_get_data(+Ref,-Data) */
 #define arg_ref  YAP_ARG1
 #define arg_data YAP_ARG2
 static int p_itrie_get_data(void) {
@@ -323,7 +322,7 @@ static int p_itrie_get_data(void) {
 #undef arg_data
 
 
-/* itrie_traverse(-Itrie,+Ref) */
+/* itrie_traverse(+Itrie,-Ref) */
 #define arg_itrie YAP_ARG1
 #define arg_ref   YAP_ARG2
 static int p_itrie_traverse_init(void) {
@@ -344,7 +343,7 @@ static int p_itrie_traverse_init(void) {
 #undef arg_ref
 
 
-/* itrie_traverse(-Itrie,+Ref) */
+/* itrie_traverse(+Itrie,-Ref) */
 #define arg_itrie YAP_ARG1
 #define arg_ref   YAP_ARG2
 static int p_itrie_traverse_cont(void) {
@@ -361,7 +360,7 @@ static int p_itrie_traverse_cont(void) {
 #undef arg_ref
 
 
-/* itrie_remove_entry(-Ref) */
+/* itrie_remove_entry(+Ref) */
 #define arg_ref   YAP_ARG1
 static int p_itrie_remove_entry(void) {
   /* check arg */
@@ -375,7 +374,7 @@ static int p_itrie_remove_entry(void) {
 #undef arg_ref
 
 
-/* itrie_remove_subtree(-Ref) */
+/* itrie_remove_subtree(+Ref) */
 #define arg_ref   YAP_ARG1
 static int p_itrie_remove_subtree(void) {
   /* check arg */
@@ -389,7 +388,7 @@ static int p_itrie_remove_subtree(void) {
 #undef arg_ref
 
 
-/* itrie_add(-ItrieDest,-ItrieSource) */
+/* itrie_add(+ItrieDest,+ItrieSource) */
 #define arg_itrie_dest   YAP_ARG1
 #define arg_itrie_source YAP_ARG2
 static int p_itrie_add(void) {
@@ -407,7 +406,7 @@ static int p_itrie_add(void) {
 #undef arg_itrie_source
 
 
-/* itrie_subtract(-ItrieDest,-ItrieSource) */
+/* itrie_subtract(+ItrieDest,+ItrieSource) */
 #define arg_itrie_dest   YAP_ARG1
 #define arg_itrie_source YAP_ARG2
 static int p_itrie_subtract(void) {
@@ -425,7 +424,7 @@ static int p_itrie_subtract(void) {
 #undef arg_itrie_source
 
 
-/* itrie_join(-ItrieDest,-ItrieSource) */
+/* itrie_join(+ItrieDest,+ItrieSource) */
 #define arg_itrie_dest   YAP_ARG1
 #define arg_itrie_source YAP_ARG2
 static int p_itrie_join(void) {
@@ -443,7 +442,7 @@ static int p_itrie_join(void) {
 #undef arg_itrie_source
 
 
-/* itrie_intersect(-ItrieDest,-ItrieSource) */
+/* itrie_intersect(+ItrieDest,+ItrieSource) */
 #define arg_itrie_dest   YAP_ARG1
 #define arg_itrie_source YAP_ARG2
 static int p_itrie_intersect(void) {
@@ -461,7 +460,7 @@ static int p_itrie_intersect(void) {
 #undef arg_itrie_source
 
 
-/* itrie_count_join(-Itrie1,-Itrie2,+Entries) */
+/* itrie_count_join(+Itrie1,+Itrie2,-Entries) */
 #define arg_itrie1   YAP_ARG1
 #define arg_itrie2   YAP_ARG2
 #define arg_entries YAP_ARG3
@@ -483,7 +482,7 @@ static int p_itrie_count_join(void) {
 #undef arg_entries
 
 
-/* itrie_count_intersect(-Itrie1,-Itrie2,+Entries) */
+/* itrie_count_intersect(+Itrie1,+Itrie2,-Entries) */
 #define arg_itrie1   YAP_ARG1
 #define arg_itrie2   YAP_ARG2
 #define arg_entries YAP_ARG3
@@ -505,7 +504,7 @@ static int p_itrie_count_intersect(void) {
 #undef arg_entries
 
 
-/* itrie_save(-Itrie,-FileName) */
+/* itrie_save(+Itrie,+FileName) */
 #define arg_itrie YAP_ARG1
 #define arg_file  YAP_ARG2
 static int p_itrie_save(void) {
@@ -533,7 +532,7 @@ static int p_itrie_save(void) {
 #undef arg_file
 
 
-/* itrie_save_as_trie(-Itrie,-FileName) */
+/* itrie_save_as_trie(+Itrie,+FileName) */
 #define arg_itrie YAP_ARG1
 #define arg_file  YAP_ARG2
 static int p_itrie_save_as_trie(void) {
@@ -561,7 +560,7 @@ static int p_itrie_save_as_trie(void) {
 #undef arg_file
 
 
-/* itrie_load(+Itrie,-FileName) */
+/* itrie_load(-Itrie,+FileName) */
 #define arg_itrie YAP_ARG1
 #define arg_file  YAP_ARG2
 static int p_itrie_load(void) {
@@ -581,10 +580,9 @@ static int p_itrie_load(void) {
     return FALSE;
 
   /* load itrie and close file */
-  itrie = itrie_load(file);
-  if (fclose(file))
+  if (!(itrie = itrie_load(file)))
     return FALSE;
-  if (!itrie)
+  if (fclose(file))
     return FALSE;
   return YAP_Unify(arg_itrie, YAP_MkIntTerm((YAP_Int) itrie));
 }
@@ -592,7 +590,49 @@ static int p_itrie_load(void) {
 #undef arg_file
 
 
-/* itrie_stats(+Memory,+Tries,+Entries,+Nodes) */
+/* itrie_save2stream(+Itrie,+Stream) */
+#define arg_itrie  YAP_ARG1
+#define arg_stream YAP_ARG2
+static int p_itrie_save2stream(void) {
+  FILE *file;
+
+  /* check args */
+  if (!YAP_IsIntTerm(arg_itrie))
+    return FALSE;
+  if ((file = (FILE*) YAP_FileDescriptorFromStream(arg_stream)) == NULL)
+    return FALSE;
+
+  /* save itrie */
+  itrie_save((TrEntry) YAP_IntOfTerm(arg_itrie), file);
+  return TRUE;
+}
+#undef arg_itrie
+#undef arg_stream
+
+
+/* itrie_loadFromStream(-Itrie,+Stream) */
+#define arg_itrie  YAP_ARG1
+#define arg_stream YAP_ARG2
+static int p_itrie_loadFromStream(void) {
+  TrEntry itrie;
+  FILE *file;
+
+  /* check args */
+  if (!YAP_IsVarTerm(arg_itrie)) 
+    return FALSE;
+  if (!(file = (FILE*) Yap_FileDescriptorFromStream(arg_stream)))
+    return FALSE;
+
+  /* load itrie */
+  if (!(itrie = itrie_load(file)))
+    return FALSE;
+  return YAP_Unify(arg_itrie, YAP_MkIntTerm((YAP_Int) itrie));
+}
+#undef arg_itrie
+#undef arg_stream
+
+
+/* itrie_stats(-Memory,-Tries,-Entries,-Nodes) */
 #define arg_memory  YAP_ARG1
 #define arg_tries   YAP_ARG2
 #define arg_entries YAP_ARG3
@@ -618,7 +658,7 @@ static int p_itrie_stats(void) {
 #undef arg_nodes
 
 
-/* itrie_max_stats(+Memory,+Tries,+Entries,+Nodes) */
+/* itrie_max_stats(-Memory,-Tries,-Entries,-Nodes) */
 #define arg_memory  YAP_ARG1
 #define arg_tries   YAP_ARG2
 #define arg_entries YAP_ARG3
@@ -644,7 +684,7 @@ static int p_itrie_max_stats(void) {
 #undef arg_nodes
 
 
-/* itrie_usage(-Itrie,+Entries,+Nodes,+VirtualNodes) */
+/* itrie_usage(+Itrie,-Entries,-Nodes,-VirtualNodes) */
 #define arg_itrie        YAP_ARG1
 #define arg_entries      YAP_ARG2
 #define arg_nodes        YAP_ARG3
@@ -672,7 +712,7 @@ static int p_itrie_usage(void) {
 #undef arg_virtualnodes
 
 
-/* itrie_print(-Itrie) */
+/* itrie_print(+Itrie) */
 #define arg_itrie YAP_ARG1
 static int p_itrie_print(void) {
   /* check arg */
@@ -684,44 +724,3 @@ static int p_itrie_print(void) {
   return TRUE;
 }
 #undef arg_itrie
-
-/* added by nf: itrie_save2stream(+Itrie,+Stream) */
-#define arg_itrie   YAP_ARG1
-#define arg_stream  YAP_ARG2
-static int p_itrie_save2stream(void) {
-  FILE *file;
-
-  /* check args */
-  if (!YAP_IsIntTerm(arg_itrie))
-    return FALSE;
-  if ((file=(FILE*)YAP_FileDescriptorFromStream(arg_stream))==NULL)
-    return FALSE;
-
-  /* save itrie and close file */
-  itrie_save((TrEntry) YAP_IntOfTerm(arg_itrie), file);
-  return TRUE;
-}
-#undef arg_itrie
-#undef arg_stream
-
-/* added by nf: itrie_loadFromStream(-Itrie,+Stream) */
-#define arg_itrie YAP_ARG1
-#define arg_stream  YAP_ARG2
-static int p_itrie_loadFromStream(void) {
-  TrEntry itrie;
-  FILE *file;
-
-  /* check args */
-  if (!YAP_IsVarTerm(arg_itrie)) 
-    return FALSE;
-  if (!(file=(FILE*)Yap_FileDescriptorFromStream(arg_stream)))
-    return FALSE;
-
-  /* load itrie and close file */
-  itrie = itrie_load(file);
-  if (!itrie)
-    return FALSE;
-  return YAP_Unify(arg_itrie, YAP_MkIntTerm((YAP_Int) itrie));
-}
-#undef arg_itrie
-#undef arg_stream
diff --git a/library/tries/tries.c b/library/tries/tries.c
index 111cd89c1..9e58fc1fb 100644
--- a/library/tries/tries.c
+++ b/library/tries/tries.c
@@ -104,13 +104,13 @@ void init_tries(void) {
 /*      Backwards Compatibility      */
 /* --------------------------------- */
 
-/* open_trie(+Trie) */
+/* open_trie(-Trie) */
 static int p_open_trie(void) {
   return p_trie_open();
 }
 
 
-/* close_trie(-Trie) */
+/* close_trie(+Trie) */
 static int p_close_trie(void) {
   return p_trie_close();
 }
@@ -122,7 +122,7 @@ static int p_close_all_tries(void) {
 }
 
 
-/* put_trie_entry(-Mode,-Trie,-Entry,+Ref) */
+/* put_trie_entry(+Mode,+Trie,+Entry,-Ref) */
 #define arg_mode  YAP_ARG1
 #define arg_trie  YAP_ARG2
 #define arg_entry YAP_ARG3
@@ -156,7 +156,7 @@ static int p_put_trie_entry(void) {
 #undef arg_ref
 
 
-/* get_trie_entry(-Mode,-Ref,+Entry) */
+/* get_trie_entry(+Mode,+Ref,-Entry) */
 #define arg_mode  YAP_ARG1
 #define arg_ref   YAP_ARG2
 #define arg_entry YAP_ARG3
@@ -188,13 +188,13 @@ static int p_get_trie_entry(void) {
 #undef arg_entry
 
 
-/* remove_trie_entry(-Ref) */
+/* remove_trie_entry(+Ref) */
 static int p_remove_trie_entry(void) {
   return p_trie_remove_entry();
 }
 
 
-/* print_trie(-Trie) */
+/* print_trie(+Trie) */
 static int p_print_trie(void) {
   return p_trie_print();
 }
@@ -205,7 +205,7 @@ static int p_print_trie(void) {
 /*      Local Procedures      */
 /* -------------------------- */
 
-/* trie_open(+Trie) */
+/* trie_open(-Trie) */
 #define arg_trie YAP_ARG1
 static int p_trie_open(void) {
   TrEntry trie;
@@ -221,7 +221,7 @@ static int p_trie_open(void) {
 #undef arg_trie
 
 
-/* trie_close(-Trie) */
+/* trie_close(+Trie) */
 #define arg_trie YAP_ARG1
 static int p_trie_close(void) {
   /* check arg */
@@ -275,7 +275,7 @@ static int p_trie_mode(void) {
 #undef arg_mode
 
 
-/* trie_put_entry(-Trie,-Entry,+Ref) */
+/* trie_put_entry(+Trie,+Entry,-Ref) */
 #define arg_trie  YAP_ARG1
 #define arg_entry YAP_ARG2
 #define arg_ref   YAP_ARG3
@@ -295,7 +295,7 @@ static int p_trie_put_entry(void) {
 #undef arg_ref
 
 
-/* trie_check_entry(-Trie,-Entry,+Ref) */
+/* trie_check_entry(+Trie,+Entry,-Ref) */
 #define arg_trie  YAP_ARG1
 #define arg_entry YAP_ARG2
 #define arg_ref   YAP_ARG3
@@ -316,7 +316,7 @@ static int p_trie_check_entry(void) {
 #undef arg_ref
 
 
-/* trie_get_entry(-Ref,+Entry) */
+/* trie_get_entry(+Ref,-Entry) */
 #define arg_ref   YAP_ARG1
 #define arg_entry YAP_ARG2
 static int p_trie_get_entry(void) {
@@ -334,7 +334,7 @@ static int p_trie_get_entry(void) {
 #undef arg_entry
 
 
-/* trie_get_first_entry(-Trie,+Ref) */
+/* trie_get_first_entry(+Trie,-Ref) */
 #define arg_trie YAP_ARG1
 #define arg_ref  YAP_ARG2
 static int p_trie_get_first_entry(void) {
@@ -353,7 +353,7 @@ static int p_trie_get_first_entry(void) {
 #undef arg_ref
 
 
-/* trie_get_last_entry(-Trie,+Ref) */
+/* trie_get_last_entry(+Trie,-Ref) */
 #define arg_trie YAP_ARG1
 #define arg_ref  YAP_ARG2
 static int p_trie_get_last_entry(void) {
@@ -372,7 +372,7 @@ static int p_trie_get_last_entry(void) {
 #undef arg_ref
 
 
-/* trie_traverse(-Trie,-FirstRef,+Ref) */
+/* trie_traverse(+Trie,+FirstRef,-Ref) */
 #define arg_trie     YAP_ARG1
 #define arg_init_ref YAP_ARG2
 #define arg_ref      YAP_ARG3
@@ -397,7 +397,7 @@ static int p_trie_traverse_init(void) {
 #undef arg_ref
 
 
-/* trie_traverse(-Trie,-FirstRef,+Ref) */
+/* trie_traverse(+Trie,+FirstRef,-Ref) */
 #define arg_trie     YAP_ARG1
 #define arg_init_ref YAP_ARG2
 #define arg_ref      YAP_ARG3
@@ -416,7 +416,7 @@ static int p_trie_traverse_cont(void) {
 #undef arg_ref
 
 
-/* trie_remove_entry(-Ref) */
+/* trie_remove_entry(+Ref) */
 #define arg_ref YAP_ARG1
 static int p_trie_remove_entry(void) {
   /* check arg */
@@ -430,7 +430,7 @@ static int p_trie_remove_entry(void) {
 #undef arg_ref
 
 
-/* trie_remove_subtree(-Ref) */
+/* trie_remove_subtree(+Ref) */
 #define arg_ref YAP_ARG1
 static int p_trie_remove_subtree(void) {
   /* check arg */
@@ -444,7 +444,7 @@ static int p_trie_remove_subtree(void) {
 #undef arg_ref
 
 
-/* trie_join(-TrieDest,-TrieSource) */
+/* trie_join(+TrieDest,+TrieSource) */
 #define arg_trie_dest   YAP_ARG1
 #define arg_trie_source YAP_ARG2
 static int p_trie_join(void) {
@@ -462,7 +462,7 @@ static int p_trie_join(void) {
 #undef arg_trie_source
 
 
-/* trie_intersect(-TrieDest,-TrieSource) */
+/* trie_intersect(+TrieDest,+TrieSource) */
 #define arg_trie_dest   YAP_ARG1
 #define arg_trie_source YAP_ARG2
 static int p_trie_intersect(void) {
@@ -480,7 +480,7 @@ static int p_trie_intersect(void) {
 #undef arg_trie_source
 
 
-/* trie_count_join(-Trie1,-Trie2,+Entries) */
+/* trie_count_join(+Trie1,+Trie2,-Entries) */
 #define arg_trie1   YAP_ARG1
 #define arg_trie2   YAP_ARG2
 #define arg_entries YAP_ARG3
@@ -502,7 +502,7 @@ static int p_trie_count_join(void) {
 #undef arg_entries
 
 
-/* trie_count_intersect(-Trie1,-Trie2,+Entries) */
+/* trie_count_intersect(+Trie1,+Trie2,-Entries) */
 #define arg_trie1   YAP_ARG1
 #define arg_trie2   YAP_ARG2
 #define arg_entries YAP_ARG3
@@ -524,7 +524,7 @@ static int p_trie_count_intersect(void) {
 #undef arg_entries
 
 
-/* trie_save(-Trie,-FileName) */
+/* trie_save(+Trie,+FileName) */
 #define arg_trie YAP_ARG1
 #define arg_file YAP_ARG2
 static int p_trie_save(void) {
@@ -552,7 +552,7 @@ static int p_trie_save(void) {
 #undef arg_file
 
 
-/* trie_load(+Trie,-FileName) */
+/* trie_load(-Trie,+FileName) */
 #define arg_trie YAP_ARG1
 #define arg_file YAP_ARG2
 static int p_trie_load(void) {
@@ -572,10 +572,9 @@ static int p_trie_load(void) {
     return FALSE;
 
   /* load trie and close file */
-  data = trie_load(file);
-  if (fclose(file))
+  if (!(data = trie_load(file)))
     return FALSE;
-  if (!data)
+  if (fclose(file))
     return FALSE;
   return YAP_Unify(arg_trie, YAP_MkIntTerm((YAP_Int) data));
 }
@@ -583,7 +582,7 @@ static int p_trie_load(void) {
 #undef arg_file
 
 
-/* trie_stats(+Memory,+Tries,+Entries,+Nodes) */
+/* trie_stats(-Memory,-Tries,-Entries,-Nodes) */
 #define arg_memory  YAP_ARG1
 #define arg_tries   YAP_ARG2
 #define arg_entries YAP_ARG3
@@ -609,7 +608,7 @@ static int p_trie_stats(void) {
 #undef arg_nodes
 
 
-/* trie_max_stats(+Memory,+Tries,+Entries,+Nodes) */
+/* trie_max_stats(-Memory,-Tries,-Entries,-Nodes) */
 #define arg_memory  YAP_ARG1
 #define arg_tries   YAP_ARG2
 #define arg_entries YAP_ARG3
@@ -635,7 +634,7 @@ static int p_trie_max_stats(void) {
 #undef arg_nodes
 
 
-/* trie_usage(-Trie,+Entries,+Nodes,+VirtualNodes) */
+/* trie_usage(+Trie,-Entries,-Nodes,-VirtualNodes) */
 #define arg_trie         YAP_ARG1
 #define arg_entries      YAP_ARG2
 #define arg_nodes        YAP_ARG3
@@ -663,7 +662,7 @@ static int p_trie_usage(void) {
 #undef arg_virtualnodes
 
 
-/* trie_print(-Trie) */
+/* trie_print(+Trie) */
 #define arg_trie YAP_ARG1
 static int p_trie_print(void) {
   /* check arg */