Function tonum

lib/lua/src/lstrlib.c:264–274

#else		/* }{ */

static int tonum (lua_State *L, int arg) {
  if (lua_type(L, arg) == LUA_TNUMBER) {  /* already a number? */
    lua_pushvalue(L, arg);
    return 1;
  }
  else {  /* check whether it is a numerical string */
    size_t len;
    const char *s = lua_tolstring(L, arg, &len);
    return (s != NULL && lua_stringtonumber(L, s) == len + 1);
  }
}


static void trymt (lua_State *L, const char *mtname) {