[luatex] Will the next version of LuaTeX be based on Lua 5.3?

[Hans Hagen]

On 1/9/2015 10:24 PM, Dirk Laurie wrote:
> 2015-01-09 16:30 GMT+02:00 luigi scarso <luigi.scarso at gmail.com>:
>> On Fri, Jan 9, 2015 at 2:30 PM, Mico Loretan <loretan.mico at gmail.com> wrote:
>>>
>>> Lua 5.3, currently at the "release candidate" stage, features a new 64-bit
>>> integer data type -- up until now, the one and only numeric data type was
>>> double-precision -- and basic UTF8 support, among several new features. Is
>>> there a chance that the next version of LuaTeX will be based on Lua 5.3?
>>>
>>> Cheers, Mico
>>>
>>> Sent from my iPhone.
>>
>> Testing Lua 5.3 is on agenda after integration of token lib (which is on the
>> top of the current todo list, but we are  currently debugging a nasty mplib
>> bug).
>> Btw, we cannot guarantee that lua 5.3 will be in the next TL 2015.
>
> Lua 5.3 is Lua 5.2 with:
> 1. Genuine 64-bit integers with bit operators.
> 2. Rudimentary UTF-8 support.
> 3. Number-to-string based on internal representation,
> not human-readable format conversion.
>
> It has a lot to offer to LuaTeX.

I'm not so sure about that ... internally TeX is mostly 32 bit and the 
extra integer/float checking/conversion might as well work against us in 
terms of speed (personally I liked the only-one-number-type approach and 
it was one of the reasons for choosing Lua as language). Only extensive 
testing will show benefits. We might even decide to stick to 5.2 (at 
least for the next release) ... who knows what 5.4 will bring. As Luajit 
is (and might never be) in sync with Lua 5.3 we can also have an issue 
with the two variants not being compatible in output so that might be 
another reason for delay. (An interesting in-between can be to have 5.2 
/ 5.3 as compile option.)

Hans


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