int ss_first (struct substring);
int ss_last (struct substring);
bool ss_starts_with (struct substring, struct substring prefix);
+bool ss_starts_with_case (struct substring, struct substring prefix);
bool ss_ends_with (struct substring, struct substring suffix);
+bool ss_ends_with_case (struct substring, struct substring suffix);
size_t ss_span (struct substring, struct substring skip_set);
size_t ss_cspan (struct substring, struct substring stop_set);
size_t ss_find_byte (struct substring, char);