Re: poll on luac

[Mark Hamburg <mhamburg@...>]

on 6/2/05 6:41 PM, Luiz Henrique de Figueiredo at lhf@tecgraf.puc-rio.br
wrote:

>> For that matter, how tenable would it be to write code that could update
>> from Lua 5.0 bytecodes to Lua 5.1 bytecodes (using that as an example of a
>> minor architectural revision to the virtual machine)?
> 
> Oh, that's a whole different story... But it shouldn't be too hard.
> I guess the only problems would be the removal of OP_TFORPREP and the
> fact that the numerical codes of the opcodes has changed because new
> instructions were inserted in the middle of existing ones. There may also
> be an issue of field ordering within each instruction.
> 
> But why do you want to do this? Have you lost your Lua sources?

It's more a hypothetical question. If I ship an engine based around some
version of Lua 5.1 and have third-parties doing development on top of that
engine and not wanting to share their sources, it becomes a bit problematic
if Lua 5.2 comes along and has changes of the magnitude of Lua 5.1 v Lua 5.0
-- i.e., small but enough to keep things from just working. The luac
question about byte-order got me thinking about whether or not one could
write a tool to upgrade existing bytecode.

Mark