Re: Self-deleting weak tables?

[Edgar Toernig <froese@...>]

Jim Pryor wrote:
>
>     alpha = newobject(10,20,30)
> [...]
> If I had any way to intern argument lists, so that
> a value-sequence could be collected into a single bundle that was
> guaranteed identical to any other bundle created from the
> same value-sequence, then I could just use a single, flat, weak cache
> table, with those bundled sequences as keys.

Just put them all in a string:

    function bundle(...)
        return table.concat({...}, "/")
    end

and if profiling shows that it's too slow or generates too much
garbage (the {...} table), write a C function that puts the
binary representation into a string:

    int bundle(lua_State *L)
    {
        lua_Number buf[32]; // assume no padding
        int i, n;

        n = lua_gettop(L);
        if (n > 32)
            luaL_error(L, "sorry pal, too many arguments");
        for (i = 0; i < n; ++i)
            buf[i] = luaL_checknumber(L, i+1);
        lua_pushlstring(L, (char*)buf, n * sizeof(*buf));
        return 1;
    }

Ciao, ET.