Re: Extending Lua for multiple light userdata types

[Coda Highland <chighland@...>]

On Tue, Nov 13, 2012 at 12:29 PM, Rena <hyperhacker@gmail.com> wrote:
> On Tue, Nov 13, 2012 at 3:05 PM, Dirk Laurie <dirk.laurie@gmail.com> wrote:
>> 2012/11/13 Rena <hyperhacker@gmail.com>:
>>> On Tue, Nov 13, 2012 at 10:42 AM, Dirk Laurie <dirk.laurie@gmail.com> wrote:
>>>> 2012/11/13 Rena <hyperhacker@gmail.com>:
>>>>
>>>>> Recently I was thinking about how you might add a 64-bit integer type to Lua.
>>>>
>>>> This is only a pressing question if you need IEEE floats and 64-bit integers
>>>> in the same program, otherwise you can build Lua with 64-bit integers
>>>> as your `number`.
>>>>
>>>
>>> True, but I really prefer to leave recompiling Lua as a last resort.
>>
>> How do you envisage accommodating new types without patching
>> and recompiling Lua?
>>
>
> ...that was kind of the point of the original post. Already you have
> lua_pushlightuserdata(L, p); this could be as simple as
> lua_pushcustomuserdata(L, p, n), which functions the same as
> lua_pushlightuserdata except for adding n to the "type" value
> (LUA_TLIGHTUSERDATA + n + 1, for n = 0 to some appropriate upper
> bound), and having those types be something like union { uint64_t int;
> uint8_t byte[8]; } instead of void*. You'd only need the initial
> change to add this capability, instead of hardcoding new types into
> Lua directly.
>
> --
> Sent from my Game Boy.
>

As I said, if this is something you really want, LuaJIT already does
almost exactly that with its cdata type. If you care about low-level
data types, you're PROBABLY also interested in everything else LuaJIT
has to offer.

/s/ Adam