2-d Array

[Christoph Schreiber <luky0711@...>]

Hi everybody,
I am trying to expose my C/C++ matrix-library to lua and I'd really like my users to be able to access the data using a C-like 2-dimensional array notation, e.g. mymatrix[2][3] = 65. The code below works well but as you can see (make_rowptr) it creates a lua-user-data-object at every row access. Is this the most efficient way to get the "[][]" notation? Any ideas?


int get(lua_State* L) // exported method
{
    type* self = static_cast<T>(luaL_checkudata(L, index, TYPEID);
    lua_Integer i = luaL_checkinteger(L, 2);
    luaL_argcheck(L, 1 <= i && i <= self->m_rows, 2, "index out of range");
    make_rowptr(L, self->m_data[i - 1], self->m_cols);
    return 1;
}

void make_rowptr(lua_State* L, lua_Number* data, lua_Integer size)
{
    vector::type* self= static_cast<vector::type*>(
        lua_newuserdata(L, sizeof(vector::type)));
    self->m_delete = false;
    self->m_size = size;
    self->m_data = data;
    luaL_getmetatable(L, vector::TYPEID);
    lua_setmetatable(L, -2);
}

Thanks a lot and cheers
Chris