Function addquoted

deps/lua/src/lstrlib.c:696–723

static void addquoted (lua_State *L, luaL_Buffer *b, int arg) {
  size_t l;
  const char *s = luaL_checklstring(L, arg, &l);
  luaL_addchar(b, '"');
  while (l--) {
    switch (*s) {
      case '"': case '\\': case '\n': {
        luaL_addchar(b, '\\');
        luaL_addchar(b, *s);
        break;
      }
      case '\r': {
        luaL_addlstring(b, "\\r", 2);
        break;
      }
      case '\0': {
        luaL_addlstring(b, "\\000", 4);
        break;
      }
      default: {
        luaL_addchar(b, *s);
        break;
      }
    }
    s++;
  }
  luaL_addchar(b, '"');
}

static const char *scanformat (lua_State *L, const char *strfrmt, char *form) {
  const char *p = strfrmt;