Re: Lua and backwards compatibility - was Re: [ANN] Lua 5.3.4 (rc2) now available,

[William Ahern <william@...>]

On Thu, Jan 12, 2017 at 02:44:15PM +0000, Nagaev Boris wrote:
> On Thu, Jan 12, 2017 at 1:18 AM, William Ahern
> <william@25thandclement.com> wrote:
> > On Thu, Jan 12, 2017 at 12:02:49AM +0000, Dibyendu Majumdar wrote:
> >> On 11 January 2017 at 21:06, Hisham <h@hisham.hm> wrote:
> >> > On 11 January 2017 at 17:08, Roberto Ierusalimschy
> >> > <roberto@inf.puc-rio.br> wrote:
> >> >>> Please, do not make such a severely breaking change in a 5.3.x release.
> >> >>
> >> >> We did not realize that. It will be corrected.
> >> >
> >> > Thank you! :)
> >> >
> >>
> >> Hi,
> >>
> >> I was wondering if it is possible to consider making strong backwards
> >> compatibility guarantees for Lua from 5.3 upwards. I think this will
> >> mean some constraints to Lua's development obviously, but it would
> >> strengthen Lua 's ecosystem.
> >>
> >> The strongest argument I could make is that Lua is built on C, and
> >> imagine how difficult it would have been if C had kept changing in
> >> incompatible ways every few years, and all new C compilers stopped
> >> supporting older versions of C.
> >
> > OTOH, Lua wouldn't be the language it is today if backwards compatibility
> > was a higher priority. Features like closures over mutable variables and
> > stackful coroutines wouldn't have been developed; features which arguably
> > are now defining characteristics of Lua relative to other languages. Other
> > than Scheme, I can't think of any other non-academic language with similarly
> > powerful constructs.
> 
> Go seems to have variables mutable from closures.
> https://play.golang.org/p/o23Z6bbUTp

Ah, right. And Go effectively has stackful coroutines. It totally slipped my
mind.
 
FWIW, I meant to say that few languages have _both_ lexically-bound closures
_and_ stackful coroutines.