From: Hans Hagen <j.hagen@xs4all.nl>
To: mailing list for ConTeXt users <ntg-context@ntg.nl>,
Neven Sajko <nsajko@gmail.com>
Subject: Re: Snooping around in LMTX: Questions about Lua global variables
Date: Tue, 22 Dec 2020 19:06:31 +0100 [thread overview]
Message-ID: <20d86aea-7af4-0fec-496d-c21bed5d384a@xs4all.nl> (raw)
In-Reply-To: <CAL+bK4OGQD52aTPZ_hgHAvHmeuV6PKLMZFOY_srqxWLd2MyNgA@mail.gmail.com>
On 12/22/2020 6:36 PM, Neven Sajko wrote:
> Hello again,
>
> While learning about how to drive TeX through Lua, I decided to
> recursively list all Lua global variables (actually this is traversing
> the _G table) in the LMTX environment, half to learn more Lua, half
> for getting to know ConTeXt better.
>
> I was quite surprised by the huge size of the environment, a file that
> contains the listing of all the globals is 42 MB long! I wonder if it
> would be possible to reduce the exposed globals by replacing some of
> them by getter and setter-like functions? That seems like it would be
not sure what you refer to but even then you need to 'get' and 'set them
someplace which then involves tables ... it's just a large system and
that won't change
also, when you run such tests, don't include the characters.* tables as
most is data, and of you do it from a tex run you also see fonts and
their data (which then means shared tables too)
> much nicer and less error prone - because Lua is so dynamic, polluting
> the global namespace seems even more dangerous than in C-like
> languages. I guess it could also be more performant, because Lua would
> conceivably spend less time managing huge tables.
Wait, you traverse global tablers so their entries are *not* global.
\starttext
\startluacode
context.starttabulate { "|T|T|" }
for k, v in table.sortedhash(_G) do
context.NC() context(type(v)) context.NC() context(k)
context.NC() context.NR()
end
context.stoptabulate()
\stopluacode
\stoptext
These are global. Many come from lua itself, then there are libraries
than come with luametatex. The rest is context specific and again some
are just helper modules. I notices some 6 stray locals that I fixed.
> There were also some global variables with suspicious random variation
> in values between runs of ConTeXt: I ran my Lua script like so
> multiple times (attached, in case someone is interested in it):
>
> context s.lua
> rm s.tuc s.pdf s.log
>
> And I found that the values of some variables unpredictably and randomly vary:
Maybe weak tables?
> The variable resolvers.suffixmap.lua sometimes has the value
> "scripts", and sometimes "lua". I think this means that files with the
> file name suffix ".lua" are sometimes classified as general scripts
> and sometimes as Lua scripts. This seems like it could even be a bug?
could be but probably more a side effect ... part of that resolver stuff
is there for usage in tds and could be simplified in the meantime .. if
there are hashes they can differ per document
> The variables storage.tofmodules and storage.toftables are also
> interesting: they vary from run to run like this:
>
> tofmodules: 0.175483 0.149536 0.150493 0.150005
>
> toftables: 0.008407 0.008118 0.008395 0.008116
>
> I'd like to know what is their purpose, if it's not to involved to explain?
timers, so indeed they can differ per run
Hans
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next prev parent reply other threads:[~2020-12-22 18:06 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-22 17:36 Neven Sajko
2020-12-22 17:57 ` Neven Sajko
2020-12-22 18:15 ` Hans Hagen
2020-12-22 18:32 ` Neven Sajko
2020-12-22 19:15 ` Hans Hagen
2020-12-22 18:06 ` Hans Hagen [this message]
2020-12-22 18:13 ` Neven Sajko
2020-12-22 18:23 ` Hans Hagen
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