Function luaO_hexavalue

third-party/lua-5.5.0/src/lobject.c:197–201

lu_byte luaO_hexavalue (int c) {
  lua_assert(lisxdigit(c));
  if (lisdigit(c)) return cast_byte(c - '0');
  else return cast_byte((ltolower(c) - 'a') + 10);
}


static int isneg (const char **s) {