Sorry, I forgot to add \dim_new:N\l_myMod_myDim_dim

@bp2017 You need an expandable function in the second argument of \dim_set:Nn: your one is not (and should be protected) as it uses \int_step_inline:nn

What package does \IfFileExists belong to?

@FaheemMitha LaTeX kernel

@JosephWright So no package required?

Just echoing what is written here.

I'm getting a puzzling error. Can anyone make an educated guess what the problem is based on the error message? I think that an MWE from where I am right now would be quite a lot of effort.

! Missing \endgroup inserted.
<inserted text>
\endgroup
l.208 \end{letter}

Is this simply a missing bracket or something? I was trying to clean up my file, and somehow caused this error, though I can't for the life of me figure out what is causing it.

@FaheemMitha No, it's defined in latex.ltx, so as long as you are not using plain ...

@FaheemMitha No, we'll need an example

@JosephWright Ok

@JosephWright It looks like my call to \directlua is a problem. Though I was using it till now with no issues.

Checking syntax.

@FaheemMitha There will be more to it: example please

@JosephWright Boiling it down to something simple won't be that easy, but I'll have to do that if I can't figure it out.

@FaheemMitha You can try removing chunks of the document body to see if the error goes away. Remove one half at a time, taking care not to remove half an environment, equation, or similar of course. The key is binary search; it takes O(log(n)) attempts to locate a problem in n lines of code.

@HaraldHanche-Olsen I already know roughly where the issue is. The puzzling thing is that all that code was working fine till now.

@FaheemMitha Then maybe you can make an MWE by removing everything else?

@HaraldHanche-Olsen Yes. Though the code isn't that simple. And it uses sqlite reading from a text file, so I'll have to construct a dummy text file too.

@FaheemMitha Well, the dummy text file problably only needs to be one line long. Perhaps empty, even.

@HaraldHanche-Olsen Possibly.

@UlrikeFischer, @DavidCarlisle Pretty sure link breaking is working properly

Found it. Accidentally removed a `` from some TeX code inside the Lua code. Sigh.

That's half an hour of my life I'll never get back.

@FaheemMitha There's a reason in the main I'd say do Lua stuff in Lua, TeX stuff in TeX

@JosephWright I'd like to, but the logic is kind of mixed up. I guess I could post my code for comment. If I'm lucky people will tell me how dreadful it is.

Though I don't think U&L is exactly set up for that. And there's a Code Review site, but I doubt there are many TeX people there.

@FaheemMitha If you look at ConTeXt (which is the model for LuaTeX use, really), they avoid too much mixing

Sorry, I should have written, removed a `` from some TeX code.

@FaheemMitha Losing time due to silly mistakes seems to be a constant of life. I have lost countless hours of my life that way.

@FaheemMitha If you post to Code Review and let people here know, I'm sure you'll get some comment

Bugger. It's a \. Why does it get removed if I place it between ``?

@MarcelKrüger PR?

@FaheemMitha Ah, the fun of Markdown in chat

@HaraldHanche-Olsen TeX's error message system could be better.

But we all already know that.

The best error reporting system I've ever seen is Common Lisp, but nobody uses it.

I guess humans are just masochistic.

@JosephWright I think the trick is to use more backticks. \ ← three needed before & after

@HaraldHanche-Olsen :)

@FaheemMitha I use CL from time to time. Yes, their whole error handling system is brilliant, though a bit hard to learn.

@HaraldHanche-Olsen It's a bit hard to get used to all the usual syntax gone missing.

It's like if someone removed all the signposts in a town.

@HaraldHanche-Olsen What do you use CL for?

@JosephWright Yes, I hear ConTeXt is using Lua a lot now. How is that working out for them?

@FaheemMitha They've been using LuaTeX for 10+ years ...

@JosephWright Oh.

@FaheemMitha MkIV has been co-developed with LuaTeX

@JosephWright Why are they making such heavy use of Lua, when the LaTeX project isn't?

@FaheemMitha ConTeXt has a different history and aims to LaTeX. ConTeXt has a relatively small user base, and doesn't have the stability aims of LaTeX. At the same time, ConTeXt is relatively monolithic compared to LaTeX: most of the code is written by the ConTeXt team. They can therefore make very different decisions.

@JosephWright I see. Thank you for explaining.

@FaheemMitha For LaTeX, we are moving to more stuff being in the kernel (partly, this is my fault, as @DavidCarlisle will confirm). But we still want to support pdfTeX, XeTeX, DVI mode, (u)pTeX, ...

CR has 34 questions tagged with tex.

@FaheemMitha ConTeXt can do stuff 'out of the box' that LaTeX can't, precisely because it's got a clear line on 'things can change' and 'you need the latest engine'

@JosephWright Yes, of course. Can't leave those users by the wayside.

@FaheemMitha Lua doesn't automatically solve issues

@JosephWright So, not so much backwards compatibility?

@JosephWright I realise that.

@FaheemMitha Er, well then don't just break stuff all the time, but if you use ConTeXt you do have to be ready to adapt your input, certainly once you go outside of core functions

@JosephWright then -> they?

@FaheemMitha Yes, sorry

@FaheemMitha These days, mostly for simple tasks, like text transformations. In the past, we were running online midterm exams using a system I wrote in CL. But we stopped doing that years ago. I haven't written any CL code for a few years now. The only lisp I write these days, is elisp.

@JosephWright I've sent it now, but it got slightly more complicated than I expected because of missing support for allocating \luafunctions. So I only did strcmp for know to clear this up first.

@MarcelKrüger Cool, just saw the email

@MarcelKrüger Team meeting just at the moment ...

@FaheemMitha I've written my PhD thesis (2008) and now an upcoming book in ConTeXt, and I find it very nice to work with. The most common user commands (section/tables/figures/math) is the same today as when I wrote my thesis (perhaps except some mkii/mkiv changes). Now, I compile the upcoming book with ConTeXt lmtx (the latest), and it works just fine. Of course, there are no guarantees...

@mickep That's interesting. I know nothing about Context. Why do you use it instead of LaTeX?

@HaraldHanche-Olsen Wow, you wrote a system in CL? Why did you stop using it?

@FaheemMitha We were using it in two first-year calculus courses, and stopped using it when the teaching of those courses underwent a major reform. Not my decision, really, but I was quite relieved, for I got to babysit the system for a weak each semester when it was in use. So I was quite happy to retire it.

@mickep -- Not to denigrate ConTeXt, but since it is so monolithic, it's not easy to adapt it to radically different output formats. This has shown itself with submissions to TUGboat -- there hasn't been one that didn't have to be hacked, sometimes considerably, to match the default TUGboat format. It's also one of the reasons that the AMS will not accept journal submissions prepared with ConTeXt; too much effort would be involved to create the equivalent of the LaTeX class files.

@FaheemMitha I think it is easier (more intuitive) to set documents up as I want them. But I also use LaTeX, when writing papers (mathematics).

@barbarabeeton I understand that one uses LaTeX for TUGboat, and that journals do not accept submissions written in ConTeXt. I don't know what hacking you had to do to match the TUGboat format, but I find ConTeXt easier to set up the way I want. I guess that just depends on what you are used to work with...

@FaheemMitha uh, weak → week … I know how to spell, but my fingers don't always.

@HaraldHanche-Olsen Were you using it for scheduling, or to create exams or something else?

@mickep I see. Like everyone else, I started with using LaTeX.

So I have no experience with ConTeXt.

@HaraldHanche-Olsen I think, other things be equal, I would quite enjoy working with CL. But oc course it depends what you are doing with it, and what your other priorities are.

Though a language like CL really comes into its own when doing difficult and possibly complicated things.

@mickep -- Actually, there's a plain TeX style for TUGboat, and quite a few people use it, as well as AMS-TeX. (That's what was used "at the beginning", before LaTeX was available. And the TUGboat "boilerplate" pages are still plain TeX; it "just works".) Some TUGboat submissions also arrive in Markdown, but that's easily converted to LaTeX. Efforts at providing a "template" for ConTeXt submissions have failed. Maybe we need to find an experienced volunteer who cares enough to develop one.

@barbarabeeton Doesn't ConTeXt have its own version of LaTeX class files?

@FaheemMitha -- I haven't used ConTeXt enough to answer that authoritatively. It probably does, but the vocabulary for sectioning and other elements, particularly environments, is quite dissimilar to the LaTeX vocabulary.

@barbarabeeton Ok. I just looked at a ConTeXt question (by mickep), and the answer starts with:

> If you don't mind modifying your source file a little bit, here is a solution using the translate module.

Yikes.

@JosephWright -- What could cause stackexchange to log me off? (That just happened, and I haven't any idea why.)

Hang on, maybe I'm misunderstanding what source file means.

Yes, I was misunderstanding. For some reason I jumped to the conclusion that the author meant the ConTeXt source. Silly me.

@FaheemMitha Not really

Stylistic question for LuaTeX users. I'm constructing a table using Lua. But the beginning and end part of the table don't use Lua. Should I extract those from the Lua file, and put them in the TeX file? Then the Lua file will only have code for constructing the rows. Currently the Lua file has all the table related code.

@JosephWright Ok.

@barbarabeeton Why not try asking a question here?

Maybe with a bounty.

@FaheemMitha -- While asking that question sounds like a good idea, I'm afraid that it doesn't adhere to the rules of the site, so it would simply be closed. It's a "do it for me" question.

@barbarabeeton It's possible the mods (and users) would make an exception. :-) Why not ask on Meta if you are concerned?

I think everyone in the TeX world knows who you are.

@FaheemMitha -- Whether or not that's true, the rules is the rules. It wouldn't look good to try to ask the mods to "play favorites".

@FaheemMitha We had a pool of multiple-choice questions, and each student would get different questions drawn at random. They would register with an invigilator, get a password, log in, and anser the questions online.

@barbarabeeton Your call. But I don't think it's a big deal.

Or you could just ask for help on the ConTeXt mailing lists.

@HaraldHanche-Olsen I see. That sounds relatively straight-forward. Though I'm sure there were bugs.

@StefanKottwitz my browser tells me that the certificate of texwelt.de is no longer valid.

@FaheemMitha -- Well, I'll have to sign up for the ConTeXt mailing list first, but that's a reasonable idea.

Like I said, CL really comes into its own when pushed. IMO, anyway. Not that I'm an expert - far from it.

@barbarabeeton Glad you think so.

CL and TeX are sort of distant cousins in a sense. They both look a bit weird on first acquaintance, but within their respective domains, they can pretty much do anything.

@FaheemMitha Oh, there was a lovely bug that caused the the whole system to hang at random. I don't think it was my fault; it only appeared with one release of the CL implementation. As a result, I started running a watchdog process that would kill and restart the process if it got unresponsive.

@FaheemMitha Just like any Turing-complete language.

@PauloCereda Try doing "anything" with Java and see how far you get.

@HaraldHanche-Olsen That sounds like a pain. What CL implementation.

@FaheemMitha I do stuff with Java. Do you know what a Turing-complete language is?

@PauloCereda I do.

@FaheemMitha I used CMUCL.

Actually, C++ is an even better example. Hideous language.

@HaraldHanche-Olsen Oh. How long ago was this? SBCL is usually the goto these days. Along with CCL.

@FaheemMitha I started out in 2003. Last time was 2012. I think the reason I went with CMUCL is that it had threading support that was missing in SBCL at the time. But it's long enough ago, I may remember it wrong.

@JosephWright, thank you.

@HaraldHanche-Olsen That's a long time ago.

@UlrikeFischer Thanks, renewed!

/duck

This is a very cool layout. I have to TeX it.

@bp2017 You can't have non-expandable material in the second argument of \dim_set:Nn. You simply cannot use \int_step_inline:nn there: you'll need \int_step_function:nN.

@JosephWright, got it. Thank you.

One of my best B-day gifts :) @JosephWright @DavidCarlisle @barbarabeeton @PauloCereda

@yo' YAY

@PauloCereda have you seen the percents? :)

@yo' -- Aha! Brought some of that back from a European trip for Gordon. He was very appreciative. Happy birthday!

@yo' I did! Quite high!

@barbarabeeton thank you! Well, Scotch is always awesome, especially if someone knows what to pick :-)

@PauloCereda still I was told it's drinkable as-is. I'm yet to try it, actually, but I don't wanna open the bottle alone :)

@yo' Invite us!

@StefanKottwitz well, if you get yourself to Prague :-)

@yo' Er ...

Actually, it's far from the only bottle of Scotch I have :-)

@yo' Bär and Marmot currently have only 57.8% ;-(. But lots of other bottles.

@UlrikeFischer Cambeltown have some nice stuff :-)

@yo' Ok! Wish me luck. So short term, I just got waitlist for tonight's flight to Prague.

@StefanKottwitz are you kidding me? (I mean, no big deal, I have a spare mattress here :) )

@yo' -- All good stuff here. Too bad I don't like whisk[e]y. But Metaxa 12, now that's more to my taste.

@barbarabeeton metaxa 5 and 7 is tasteless. The 12 is really nice! And you might also like my Madagascar rum (it's missing from the shelf)

@yo' Well, testing the flight booking software :-)

@yo' -- Oh, yes! Have never had Madagascar rum, but it sounds interesting. What do you think of rum agricole?

@StefanKottwitz Aha!

@barbarabeeton Sounds very similar to cachaça, which I have at home, thanks to @PauloCereda 's dad

@yo' -- Probably. Rum agricole is made directly from pressed sugarcane, without intermediate molasses.

@barbarabeeton yeah. Well, cachaça is basically a sugarcane distillate (similar to slivovice [plum distillate] or calvados [apple distillate])

@StefanKottwitz Speaking of FRA, I'll be there on Friday ...

@JosephWright Layover? Connecting flight? to where?

@StefanKottwitz NWI-AMS AMS-FRA: team meeting next weekend :)

@JosephWright AMS-FRA by plane is almost a sin :D However, for you it's probably the longer of the two flights, right?

@yo' Have you looked at distance for NWI-AMS ;)

@JosephWright see my edit :D

However, that one is overseas, so there it's different

lol, Schiphol -- Frankfurt Flughafen by train: 4:42 and 1 change

* ripping out (not off, correction)

@JosephWright and I hang out in London June 12th to June 22nd

@bp2017 Why not frame the \parbox?

@PhelypeOleinik, because \parbox also contains text that shouldn't be framed. And I wouldn't know whether the text is spread several lines until \parbox finishes processing it. It would've been helpful to have access to absolute position of the box enclosing each letter in the \parbox or something like this (to put the coordinates into tikz and draw a box).

In other words, the frame must "morph" to the text: if the text spans several lines, frame spans with the text.

@bp2017 Well, that is an entire new problem. You don't have much control of anything after TeX has broken the text into lines. You might want to take a look at the soul and ulem packages which do underlining and similar things, but its a lot more of work. Perhaps some clever Lua code. I suggest you ask a question about this instead of the chat.

@PhelypeOleinik, I ran out of my monthly question-limit (can't post). I keep hearing about how handy Lua is, but it's yet another learning curve (not enough time for that at this point). Anyway, thank you.

@bp2017 Oh, wow. I didn't even know that limit exist. Again, I think it should be possible with other engines if you adapt some code in ulem or soul, but it's most certainly very far from trivial.

@bp2017 There's a monthly question limit?

@StefanKottwitz You're on the internet even in a plane? I thought Lufthansa provides wifi only on intercontinentals :)

@StefanKottwitz How was your flight? :)

@yo' No good Scotch there.

@StefanKottwitz Oooh, where exactly?

@JosephWright During work hours, at the Cisco Customer Experience Center, Bedfont Lakes, near the airport.

@StefanKottwitz Ah, right

@JosephWright Testing software defined networking there

@StefanKottwitz Right, got it: sounds fun :)

@JosephWright should be ok :-) I look forward to meet friends in London after work

Math withing $...$ along with $ signs would be treated as a token group, not a regular text (I still need it as tokens, not grouped together), might I add.

@bp2017 Sounds like a reasonable standalone question to me.

I mean, for the site. It's unlikely that someone else has asked something like this, i would have thought.

Honestly, I'm not even sure what you are asking. Or why.