Re: [NTG-context] Using ConTeXt-LMTX for modern Mathematically-Literate-Programming 2/2
Hans, If my only constraints were ease of programming and moderate performance, I would completely agree that using mostly Lua plus (possibly) some C code for some targeted stuff that is really slow in Lua is the correct solution we are actually in agreement. Unfortunately, I have the *non-functional* requirement to *prove* the code's correctness this is the heart of what I have to write about. There is no getting out of this requirement So, some day it would be very useful to be able to directly embed a Lua wrapped ANSI-C shared library inside the new LuaMetaTex However, at the moment, as part of my parallelization attempts I can interact with my ANSI-C code over a network so I will use this approach for the near to medium time frames. Regards, Stephen Gaito On Wed, 2 Dec 2020 14:17:54 +0100 Hans Hagen wrote: > On 12/2/2020 11:43 AM, Stephen Gaito wrote: > > > Again, to my knowledge, Lua v5.4 has only one implementation (though > > this implementation *can* be compiled for a very wide range of > > CPU's). > > Lua has not many demands ... it can even run on tiny cpu's. It's all > rather plain C code. (And in luametatex we have no c++ ... all is > just C.) > > > Finally, the computational complexity of my proof engine, will be > > comparable to MetaFun/MetaPost... which I suspect you would not > > consider implementing in pure Lua. Some things are faster in C. > > Hard to say ... I think that the parser / expansion machinery in mp > is the bottleneck here (no fun to do that in lua). Redoing it in Lua > also is asking for compatibility issues. (btw, extensions are done in > lua anyway, as is the mp backend) > > > So yes I do need to implement it in ANSI-C wrapped in Lua (so that > > it can be used from *inside* ConTeXt). > > I would have to see the 'kind of code involved' in order to comment > on that. > > An option is to do most in lua and maybe some helpers for crititical > code in C. > 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 > - ___ If your question is of interest to others as well, please add an entry to the Wiki! maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context webpage : http://www.pragma-ade.nl / http://context.aanhet.net archive : https://bitbucket.org/phg/context-mirror/commits/ wiki : http://contextgarden.net ___
Re: [NTG-context] Using ConTeXt-LMTX for modern Mathematically-Literate-Programming 2/2
On 12/2/2020 11:43 AM, Stephen Gaito wrote: Again, to my knowledge, Lua v5.4 has only one implementation (though this implementation *can* be compiled for a very wide range of CPU's). Lua has not many demands ... it can even run on tiny cpu's. It's all rather plain C code. (And in luametatex we have no c++ ... all is just C.) Finally, the computational complexity of my proof engine, will be comparable to MetaFun/MetaPost... which I suspect you would not consider implementing in pure Lua. Some things are faster in C. Hard to say ... I think that the parser / expansion machinery in mp is the bottleneck here (no fun to do that in lua). Redoing it in Lua also is asking for compatibility issues. (btw, extensions are done in lua anyway, as is the mp backend) So yes I do need to implement it in ANSI-C wrapped in Lua (so that it can be used from *inside* ConTeXt). I would have to see the 'kind of code involved' in order to comment on that. An option is to do most in lua and maybe some helpers for crititical code in C. 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 - ___ If your question is of interest to others as well, please add an entry to the Wiki! maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context webpage : http://www.pragma-ade.nl / http://context.aanhet.net archive : https://bitbucket.org/phg/context-mirror/commits/ wiki : http://contextgarden.net ___
Re: [NTG-context] Using ConTeXt-LMTX for modern Mathematically-Literate-Programming 2/2
Hans,
Many thanks for your comments... see below.
On Mon, 30 Nov 2020 19:31:55 +0100
Hans Hagen wrote:
> On 11/30/2020 10:51 AM, Stephen Gaito wrote:
> > Hello (again),
> >
> > This email is further to my previous "Using ConTeXt-LMTX for modern
> > Mathematically-Literate-Programming 1/2" email...
> >
> > My ultimate goal in using ConTeXt-LMTX as a
> > Mathematically-Literate-Programming tool, is to actually write a
> > kernel "Mathematical Language" in ANSI-C (wrapped in Lua) which is
> > then imported back into ConTeXt-LMTX as a standard Lua module (with
> > an ANSI-C shared library).
>
> Just curious: do you think that using c instead of lua for that has
> advantages?
This is a very good and important question. One I have asked myself
repeatedly.
My ultimate goal is to write a small mathematical kernel in ANSI-C,
which is, using [Frama-C](https://frama-c.com/), proven *correct*.
To my knowledge, Lua has no similar tool for correctness proofs.
Equally importantly, there are a very wide range of very different
compilers which compile ANSI-C for an equally very wide range of CPU's.
Again, to my knowledge, Lua v5.4 has only one implementation (though
this implementation *can* be compiled for a very wide range of CPU's).
The problem here is that Mathematicians are inherently very
conservative about the concept of "proof" (it has taken well over 2,000
hard years to develop our current understanding). My kernel will be an
extensible "proof" engine. For mathematicians to trust it, this proof
engine must itself be proven correct (or as correct as currently
possible). It must also be simple enough to *see* that it is correct
(hence the Literate-Programming approach), *and* (since I can not even
hope to prove the compilers are *correct*), there must be many
*different* compiler implementations (to show that the results are not
artefacts of one particular implementation).
Finally, the computational complexity of my proof engine, will be
comparable to MetaFun/MetaPost... which I suspect you would not
consider implementing in pure Lua. Some things are faster in C.
So yes I do need to implement it in ANSI-C wrapped in Lua (so that it
can be used from *inside* ConTeXt).
Since this is a mathematical tool, "embedding" it in ConTeXt is ideal.
As a mathematician writes, what they write gets proof-checked
automatically... in the document they are writing, and by the
typesetting tool they are using for the finished PDF. :-)
ConTeXt (via LuaMetaTex) makes this possible in a way native TeX/LaTeX
never could.
So once again, many many thanks for the vision to create such a
flexible tool!
>
> > This would allow the output of "code" in my "Mathematical Language"
> > to be directly embedded/typeset in the output of my Mathematical
> > document.
> >
> > (The ultimate goal is to ensure that there is NO wishful thinking
> > that the code is "correct" ("just trust me")... all results would be
> > directly visible in the PDF).
> >
> > Alas, while, for other reasons, trying to use the Lua-CJSON Lua
> > module from within ConTeXt-LMTX (which also makes use of a shared
> > library written in C), I find that the current ConTeXt-LMTX is
> > missing (among potentially others) the `lua_checkstack` symbol:
>
> could be .. we dont' use it
>
> >> ...Xt/tex/texmf-context/tex/context/base/mkiv/l-package.lua:333:
> >> error loading module 'cjson' from file
> >> '/usr/local/lib/lua/5.4/cjson.so':
> >> /usr/local/lib/lua/5.4/cjson.so: undefined symbol: lua_checkstack
> >
> > even when using the ConTeXt/LuaMetaTeX `--permiteloadlib` switch.
> >
> > (Note that this Lua-CJSON module does work with the native 5.4 Lua).
>
> why not use the build in helpers
The test, which triggered the error message (above), was to prove that
I could send [NATS](https://nats.io/) messages from *inside* ConTeXt.
"Out of the box", the [Lua-NATS](https://github.com/DawnAngel/lua-nats)
requires:
- luasocket (which LuaMetaTex provides, many many thanks!)
- lua-cjson (which is an external shared library and is what I was
testing)
Fortunately, I found a couple of pure Lua JSON tools which I could get
Lua-NATS to use with a one line change. (And, for the record, I *can*
send and receive messages from a NATS server from inside ConTeXt :-)
If I find I need to make changes to the Lua-NATS code, I will probably
use LuaMetaTeX's internal JSON implementation as you suggest below
(again many thanks for embedding a JSON implementation).
Using Lua-NATS is part of my larger goal to parallelize the typesetting
of large documents using ConTeXt (more on this in another email).
>
> \usemodule[json]
>
> \starttext
>
> \startluacode
> local l = { a = 1, b = { c = "d" } }
> inspect(l)
> local j = utilities.json.tojson(l)
> inspect(j)
> local s = utilities.json.tostring(j)
> inspect(s)
> io.savedata("temp.json",j)
> local t = utilities.json.load("temp.json")
> inspect(t)
> \stopluacode
>
> \stoptext
>
> >
[NTG-context] Using ConTeXt-LMTX for modern Mathematically-Literate-Programming 2/2
Hello (again),
This email is further to my previous "Using ConTeXt-LMTX for modern
Mathematically-Literate-Programming 1/2" email...
My ultimate goal in using ConTeXt-LMTX as a
Mathematically-Literate-Programming tool, is to actually write a
kernel "Mathematical Language" in ANSI-C (wrapped in Lua) which is then
imported back into ConTeXt-LMTX as a standard Lua module (with an ANSI-C
shared library).
This would allow the output of "code" in my "Mathematical Language" to
be directly embedded/typeset in the output of my Mathematical document.
(The ultimate goal is to ensure that there is NO wishful thinking that
the code is "correct" ("just trust me")... all results would be
directly visible in the PDF).
Alas, while, for other reasons, trying to use the Lua-CJSON Lua module
from within ConTeXt-LMTX (which also makes use of a shared library
written in C), I find that the current ConTeXt-LMTX is missing (among
potentially others) the `lua_checkstack` symbol:
> ...Xt/tex/texmf-context/tex/context/base/mkiv/l-package.lua:333: error
> loading module 'cjson' from file '/usr/local/lib/lua/5.4/cjson.so':
> /usr/local/lib/lua/5.4/cjson.so: undefined symbol: lua_checkstack
even when using the ConTeXt/LuaMetaTeX `--permiteloadlib` switch.
(Note that this Lua-CJSON module does work with the native 5.4 Lua).
(The ConTeXt I am using identifies itself as: ConTeXt ver: 2020.11.25
19:18 LMTX fmt: 2020.11.25 int: english/english)
I note that the output of `luametatex --help` includes the following
statement:
> Loading libraries is blocked unless one explicitly permits it (will
> be in 2.08+):
>
> --permitloadlib permit loading of external libraries (coming)
QUESTIONS:
1. Is this an oversight and `--permitloadlib` is meant to be working
now?
2. Is this a trivial fix (and might be fixed soon -- time permitting)?
3. Is this a rather complex refactoring of the code/build system (and
hence might take some time before a fix can be rolled
out)?
4. Is this a case of "the `lua_checkstack` symbol will never be part of
luametatex"?
Any of the above scenarios is OK (though scenario 4 would be a
disappointment as it means no shared library lua modules could be
used in ConTeXt)...
... it would however be useful to have an idea of which scenario is
most likely.
Again Many thanks for a wonderful (and stable) tool!
Regards,
Stephen Gaito
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