On 11/5/2021 6:23 PM, Ramkumar KB via ntg-context wrote:
Hello,
Yesterday, Roblox announced - Luau - https://luau-lang.org/why https://luau-lang.org/why - mainly adding linting and type-checking features.
Being compatible with Lua 5.1 is probably a bummer but nonetheless would be interesting to hear about this from this community. for sure i need more than an email to give a real answer (and some can be read between the lines of the history documents / articles that we ship); that said:
the main reasons for choosing lua for luatex has been that it is relatively small, has no dependencies, doesn't need tons of libraries to make it useful, is made for embeded usage, evolves in a proper academic setting, has long-term dedicated (nice) developers, is not part of some religious programming language war/competition, reminds me (in a positive way of pascal and modula), is pretty fast, ... so, no regrest and no need for something else now, the link you point at mentions 'typing', 'multipass bytecode generation', 'possible jit' to start with typing: i suppose that a more explicit integer / float separation can give better performance, although on modern cpu's one can wonder (personally i don't see the current mix of integer / float as a benefit over all numbers being floats - which had some charm due to the consistency - but who an i to complain; at least we now have bitwise operators (for a specific application like roblox it makes sense but using a dedicated / patched / extended lua machinery in luatex doesn't); there are articles by the lua authors about typing but these are behind publisher firewalls multipass compiling costs time and would actually not be that benificial: in luatex we rely a lot on instant and frequent compilation (\directlua, \latelua) which is real fast; i bet that there are some optimizations possible in the vm but at the cost of more granularity and therefore it could bring limitations too (unless one goes wider memory wise) .. i think many lua applications actually assume fast realtime compilation; we simply don't stay long enough in a run to have an advantage (apart maybe from embedded bytecode for which an optional bytecode optimizer could make sense and i actually have been thinking about that) jitting also costs time and for a single pass process like tex there is no gain (we established that long ago alreadY); the only reason why luajittex is faster than luatex for a tex run is that the vm is faster due to some limitations (that one can actually hit but in context we got around it) ... jitting also is cpu dependent and therefore more fragile futurw wise (more and more complex code too) i'd read about the roblox vm project some time ago and was curious how it would work with the latest lua but then, but for good reason they stick to 5.1; if you look at the lua vm code i guess that some gain can come from less type-checking (maybe the <const> prefix in 5.4 is some indication that there are thoughts about this but currently that has no significant gain) if better performance is an objective: there are probably spots in the current code that are candidates and one can see from updates that occasionally optimizations happen (keep in mind that lua has to run on a wide range of hardware: small embedded to fast single core) so, I'm pretty okay with lua as it is now (but any influx from spin off languages / engines can be interesting, but i think the authors are aware of all that) ... and ... who knows what (side effects) pallene will bring (also about performance: i know pretty well how to write fast lua code but no one ever comes around asking so that means everyone is satisfied) Hans ----------------------------------------------------------------- Hans Hagen | PRAGMA ADE Ridderstraat 27 | 8061 GH Hasselt | The Netherlands tel: 038 477 53 69 | www.pragma-ade.nl | www.pragma-pod.nl -----------------------------------------------------------------