int ss_at (struct substring, size_t idx);
int ss_first (struct substring);
int ss_last (struct substring);
+bool ss_starts_with (struct substring, struct substring prefix);
bool ss_ends_with (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);
+size_t ss_find_substring (struct substring, struct substring);
int ss_compare (struct substring, struct substring);
int ss_compare_case (struct substring, struct substring);
int ss_equals (struct substring, struct substring);