TeX, LaTeX and Friends

texdr.aft

4:42 AM

@ShreevatsaR I'm curious: Do you use literate programming tools regularly?

Paulo Cereda

9:05 AM

Gravity Duck - Launch Trailer

►

@JosephWright ^^ new game :)

mickep

10:59 AM

This new document from Hans about new features in ConTeXT/MetaFun could be interesting for others inhere.

4

ShreevatsaR

11:20 AM

@texdr.aft no I don't use literate programming much... though a couple of times I did give it a shot (with org-babel) and it was actually fun

Faheem Mitha

12:27 PM

@mickep Does Hans Hagen do consulting for document typesetting professionally?

mickep

@FaheemMitha I think you could look at pragma-ade.com to see what the company offers.

David Carlisle

@FaheemMitha yes that's what context was developed for

Faheem Mitha

Ok. Well, nice to know someone is making a living from TeX.

David Carlisle

@FaheemMitha anyone working for overleaf for example, not to mention the people listed here tug.org/consultants.html

Faheem Mitha

12:44 PM

@DavidCarlisle Oh, there's a list.

Aditya

4:00 PM

@FaheemMitha @HenriMenke is an expert on that

Faheem Mitha

@Aditya Ok. I see you actually tried running it with luatex. I didn't try that.

faheem@orwell:~/test-latex$ luatex julia.lua
julia.lua:11: failed to find function/global jl_init

Aditya

You need julia header files in the lib path (don't remember the details). Also note that Julia has changed quite a bit since that blog post was written

Paulo Cereda

4:17 PM

24 hours ago, by Paulo Cereda

@FaheemMitha I haven't seen the example in Aditya's page, but I am almost sure it's a LUA_CPATH issue. Regardless, try texlua instead of lua and see if it works for you.

Faheem Mitha

@Aditya Ok.

Aditya

@FaheemMitha Based on github.com/JuliaLang/julia/issues/28824, it appears that the symbol jl_init has changed to jl_init__threading

So the following works

    local ffi = require("ffi")
    local JULIA = ffi.load("julia", true)

    ffi.cdef [[
    void jl_init__threading(void);
    typedef struct _jl_value_t jl_value_t;
    jl_value_t *jl_eval_string(const char*);
    ]]

    JULIA.jl_init__threading()

    code = [[
    x = [1 2 3]'
    A = [1 0 1; 0 1 1; 1 1 0]

    y = x'*A*x

    print(y[1])
    ]]

    JULIA.jl_eval_string(code)

(What is the formatting language for chat? Markdown doesn't seem to work

Torbjørn T.

@Aditya Paste code-only in the box, then click the "fixed font" button that appears. For inline code, backticks work.

Faheem Mitha

4:37 PM

@Aditya Ok, I'll try that, thanks. Were you planning to update your blog entry?

@Aditya RROR: could not load library "/usr/lib/x86_64-linux-gnu/../bin/../lib/x86_64-linux-gnu/julia/sys.so"
/usr/lib/x86_64-linux-gnu/../bin/../lib/x86_64-linux-gnu/julia/sys.so: cannot open shared object file: No such file or directory

aheem@orwell:~/test-latex$ dlocate julia/sys.so
libjulia1: /usr/lib/x86_64-linux-gnu/julia/sys.so

Does it expect it to be in /usr/lib/x86_64-linux-gnu/bin/lib/x86_64-linux-gnu/julia?

(Assuming those dots just represent Lua string concatentation...)

Aditya

5:09 PM

@FaheemMitha Not sure why it is looking at julia/sys.so. On my system, the library is libjulia.so and is located at /usr/lib/libjulia.so

Faheem Mitha

Also, luajit gives the same error, but lua just says that the ffi library is not found. Does luatex contain the ffi library?

@Aditya What is your system?

Paulo Cereda

@FaheemMitha The path is not canonical, so the .. represent the upper directory in the filesystem hierarchy.

Aditya

@FaheemMitha Yes, run using luatex rather than lua

@TorbjørnT. Thanks

Faheem Mitha

@Aditya Yes, but my question is whether LuaTeX contains the FFI library. I think it's possible it does.

Aditya

Yes, it does

Faheem Mitha

5:12 PM

@Aditya Ok, thanks.

My system (Debian buster) also has libjulia.so. Julia version 1.0.3+dfsg-4. What is yours, again?

Aditya

Archlinux

with Julia 1.1.1-1

Faheem Mitha

5:44 PM

@Aditya Hmm. Might be a version thing.

I don't know anything about Julia. Or Arch, really.

@Aditya What Arch version?

1.1.1+dfsg-1 in Debian unstable.

I could try to upgrade it.

Aditya

@FaheemMitha Archlinux is a rolling release, so there are no versions. If you are not familiar with Julia, why are you trying to embed julia in lua :-)

Faheem Mitha

@Aditya Trying to see what's possible.

Aditya

What happens when you run luatex filename?

Faheem Mitha

I've not particularly familiar with Julia, but I've used similar things before.

@Aditya Huh?

Just upgrading to Julia 1.1.1+dfsg-1. Same error.

Aditya

Are you trying to compile the .lua file with lua or luatex. Do you get the same error when using luatex?

What is the exact command that you are using, and what is the exact error message

Faheem Mitha

5:53 PM

:51363074 faheem@orwell:~/test-latex$ luatex julia.lua
ERROR: could not load library "/usr/lib/x86_64-linux-gnu/../bin/../lib/x86_64-linux-gnu/julia/sys.so"
/usr/lib/x86_64-linux-gnu/../bin/../lib/x86_64-linux-gnu/julia/sys.so: cannot open shared object file: No such file or directory

faheem@orwell:~/test-latex$ julia --version
julia version 1.1.1

Aditya

I don't really know what is happening. You'll need to check with someone who knows how linking dynamic libs work. The code should not load julia/sys.so but libjuluia.so so not sure what is happening

Faheem Mitha

@Aditya Ok. Is it ok with you if I post it on the site? With suitable attribution to your blog post, of course.

Aditya

Sure

Faheem Mitha

@Aditya Ok, writing a question now. Can you confirm that the (slightly) modifed code that you posted currently works on your Arch system?

StrongBad

6:15 PM

@FaheemMitha if you are talking about the block of code above, luatex julia.lua gives me 23. Is that what it is supposed to do?

I am on Arch

Faheem Mitha

@StrongBad Probably. I don't know, I didn't do the matrix multiplication.

At any rate, it's not supposed to error out. And Arch really has no versions?

StrongBad

@FaheemMitha nope. it is a rolling release that just packages things from upstream with no QA or distro supplied bug fixes. Every once in a while they need to patch something to work within the distro lay out, but usually not.

Faheem Mitha

@StrongBad And yes, I was talking about the code that Aditya wrote. It's basically what's in his blog post with a minor modification.

@StrongBad That must be an interesting ride at times.

StrongBad

@FaheemMitha it has been years since they broke everyones system and if you only use official packages up are typically automatic. For a desktop/laptop system it is fine. My lab server runs it also. Not sure I would want to use it for a production server.

Faheem Mitha

@StrongBad Debian spends a lot of time and effort making sure things work correctly. And keeping stuff synced.

I'm a little surprised that a less synchronized approach doesn't create more issues.

StrongBad

6:27 PM

@FaheemMitha but Debian also wants to freeze parts and backport other things. In reality you can run unstable and even pull packages from experimental without too many issues. I think of Arch as somewhere between those two.

Faheem Mitha

@StrongBad Leaf packages are normally not a problem on Debian. That is true.

I upgrade such things all the time.

Paulo Cereda

The FEYNMAN Problem-Solving Algorithm:

i) write down the problem;

ii) think very hard;

iii) write down the answer.

Ulrike Fischer

Paulo Cereda

@UlrikeFischer ooh

Ulrike Fischer

@DavidCarlisle @JosephWright ^^^^ after some hard work

Joseph Wright

6:38 PM

@UlrikeFischer Cool

Ulrike Fischer

@JosephWright can one "freeze" a repo? So that nobody can add issues? I don't think that one should delete it, it has history (also in the issues).

Paulo Cereda

@UlrikeFischer Issues yes, pull requests... it's complicated. :)

Joseph Wright

@UlrikeFischer Yes, you can make it read-only

Ulrike Fischer

@PauloCereda I don't care much about pull requests - if someone doesn't realize that the code is old, the pull request can't be very good.

Joseph Wright

@UlrikeFischer Haven't we got the histroy in your repo?

Paulo Cereda

6:44 PM

@UlrikeFischer got it. :) Issues can be disabled.

Ulrike Fischer

@JosephWright not the issues. The commits should be there as I started with a fork.

Faheem Mitha

6:58 PM

@Aditya I asked the question.

Paulo Cereda

7:09 PM

@FaheemMitha Shouldn't you say LuaTeX in the title instead of just Lua?

Paulo Cereda

7:19 PM

Also, it works for me:

[paulo@satyagraha ~] $ uname -a
Linux satyagraha 5.1.19-300.fc30.x86_64 #1 SMP Mon Jul 22 16:32:45 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux
[paulo@satyagraha ~] $ texlua test.lua
23

Faheem Mitha

7:47 PM

@PauloCereda Distribution?

Paulo Cereda

@FaheemMitha Fedora

Faheem Mitha

@PauloCereda There isn't any actual TeX there. I think it would also work with LuaJIT. It requires the FFI library, which isn't in Lua. At leat, that's my understanding.

@PauloCereda Ah. Hmm.

Paulo Cereda

@FaheemMitha Well, it's not the vanilla Lua. But it does not make a difference for the question.

Faheem Mitha

@PauloCereda Agreed, it's not the vanilla Lua.

Paulo Cereda

@FaheemMitha However the body of the question clearly states the interpreter, so no harm done.

David Carlisle

7:54 PM

@UlrikeFischer github as an "archived" feature (I'm not sure if it is new, I just noticed it earlier today)

@FaheemMitha you can't give luatex a lua file, you need texlua

Faheem Mitha

@DavidCarlisle Aren't they the same thing? Anyway, I get the same error either way.

Harald Hanche-Olsen

@StrongBad 23 looks right, by mental calculation

David Carlisle

@FaheemMitha not really, even though they are symlink (although actually in tl2019 it seems like it does detect and switch back)

Faheem Mitha

@HaraldHanche-Olsen I probably could once do matrix calculations in my head. These days I'd need pen and paper.

mickep

@HaraldHanche-Olsen Mental calculation seems quicker than getting the code to run smoothly this time :)

Faheem Mitha

8:04 PM

@DavidCarlisle What's the difference? Are you saying the same executable behaves differently depending on what name it's called by? If so, that's some interesting behavior.

mickep

(and yes, I agree on 23)

Harald Hanche-Olsen

@mickep It would have been a better example if the answer were 42.

David Carlisle

@FaheemMitha almost all tex related programs have that feature, eg pdftex and pdflatex are symlinked

Faheem Mitha

@DavidCarlisle And it matters by what name they are invoked?

mickep

@HaraldHanche-Olsen Challenge: Change one entry only (to an integer) to get 42 as a result!

David Carlisle

8:06 PM

@FaheemMitha well yes pdftex gives plain tex and pdflatex gives latex.

Faheem Mitha

@DavidCarlisle Hmm.

Harald Hanche-Olsen

@FaheemMitha Technically, on unix, all programs get the calling arguments in a vector argv[]. And the zero'th argument is the name the program was called with.

Faheem Mitha

And it will give an error if you use the wrong name, even though it's the same executable?

@HaraldHanche-Olsen Yes, I know. But it's not normal for programs to use that as part of execution.

David Carlisle

@FaheemMitha texlua only accepts lua, luatex normally accepts tex, but (I now recall) if the ere is a single file with extension lua or luc then it behaves like texlua

Faheem Mitha

No reason not to do so, I suppose. Just, uncommon.

@DavidCarlisle Ok, noted.

Should I change my post, then? To avoid luring others into what are (apparently) bad habits?

Harald Hanche-Olsen

8:09 PM

@FaheemMitha The good old rsh program (unsecure predecessor of ssh) famously did: If you created a symlink to it named after a host on your network, rsh would connect to that host. So you could run just hostname instead of rsh hostname.

Faheem Mitha

@HaraldHanche-Olsen Sounds like a fun source of bugs.

Harald Hanche-Olsen

@FaheemMitha I never heard of anyone being burned by it. Of course, it would not work if you named the host rsh.

Faheem Mitha

@HaraldHanche-Olsen Ok. I've no idea. I've never used it. I've barely heard of it.

David Carlisle

@FaheemMitha looking in `/bin` I see several non-tex symlink, for example I am sure @PauloCereda will confirm `rvi` is something that is a symlink to vim and `man vim` says `Vim behaves differently, depending on the name of the command (the exe‐
cutable may still be the same file).`

Faheem Mitha

@DavidCarlisle Oh.

Harald Hanche-Olsen

8:13 PM

@FaheemMitha Well, it was way too unsecure to be used at all in the modern world.

@FaheemMitha Oh, an even better example is ex and vi. They are the same program, but ex starts in line mode and vi starts in “visual mode” (hence the name).

Faheem Mitha

@HaraldHanche-Olsen Yes, David just said something similar.

I'm not a vi user, so I'm not familiar with this behavior.

Harald Hanche-Olsen

@FaheemMitha Oh, yeah. In fact, on my mac, ex and vi are both symlinks to vim.

David Carlisle

@FaheemMitha but you've used tex for a long time:-)

Faheem Mitha

@DavidCarlisle I have, yes.

But I'm not really familiar with the internal structure.

And based on my recent installation of TeX Live 2019, it's becoming quite large and complex.

David Carlisle

@FaheemMitha latex, pdflatex, pdftex, etc have all been symlinked to tex since I think the start of the web2c implementations so late 1980s

yo'

8:22 PM

@DavidCarlisle in systems that know what a symlink is, needless to say :)

Faheem Mitha

@DavidCarlisle I guess I missed all that.

@yo' Presumably other OS's have a similar feature.

David Carlisle

@FaheemMitha yes in windows they are copies, so it comes to the same thing, they still use the program name

Faheem Mitha

Though once upon a time TeX ran on some quite exotic architectures.

David Carlisle

@FaheemMitha windows not really

Faheem Mitha

@DavidCarlisle Oh

David Carlisle

8:24 PM

@FaheemMitha texlive on windows copies the executable rather than symlinks but it is a lightweight copy as the executable is just a small stub all the real code is in a dll

Faheem Mitha

@DavidCarlisle I see.

Ulrike Fischer

@DavidCarlisle yes I saw it. It is in the "danger zone", so probably one should ask the other repo owners before clicking on the button ;-).

David Carlisle

@UlrikeFischer I don't think they will mind:-)

Ulrike Fischer

@DavidCarlisle I think I'm the newest owner so I guess I will get the blame ;-(.

David Carlisle

@UlrikeFischer naturally

StrongBad

8:32 PM

@FaheemMitha doesn't lib/x86_64-linux-gnu/../bin/../lib put you in lib/lib?

Faheem Mitha

@StrongBad I'm not sure what the ".." here means. In Unix it would normally mean go up one level. In Lua it means string concatenation. Neither of these seem to fit the context, however.

Harald Hanche-Olsen

@mickep Replace 1 in the top left corner of A by 20. The solution is unique, because 19 is a prime number.

David Carlisle

@FaheemMitha what happens if you use luajittex --shell-escape julia.lua

Faheem Mitha

9:06 PM

@DavidCarlisle I get the same error message.

Joseph Wright

@UlrikeFischer Its a +1 from me :)

Ulrike Fischer

@JosephWright ;-) (Frank said already yes too ...)

Joseph Wright