+XBT_PUBLIC(char *) xbt_str_join(xbt_dynar_t dynar, const char *sep);
+
+/* */
+XBT_PUBLIC(void) xbt_str_subst(char *str, char from, char to, int amount);
+XBT_PUBLIC(char *) xbt_str_varsubst(char *str, xbt_dict_t patterns);
+
+/* */
+XBT_PUBLIC(void) xbt_str_strip_spaces(char *);
+XBT_PUBLIC(char *) xbt_str_diff(char *a, char *b);