Speaking of floating point, if you haven't already done so, check out the numerica package by Andrew Parsloe. I think it's quite innovative.

@Rmano oh, I remember a hot conference there. And not really any place to swim...

@UlrikeFischer Anything for the agenda?

@LaTeXereXeTaL We should likely revisit user-defined variables ofr l3fp (we have the code for it, but it's currently only in the trial area), and perhaps I can get Bruno to finish the missing functions (e.g. hyperbolic ones)

@JosephWright user defined functions when? :P

@Skillmon github.com/latex3/latex3/blob/main/l3trial/l3fp-extras/…

@JosephWright optional arguments possible? E.g., round(<num>, <places>) has <places> default to 0. Variadic functions? key=value arguments? (I can think of so many niceties... :P)

@Skillmon As far as I know, the code just requires the fn to be expandable, but I'm not sure of the detail

@Skillmon I think one needs to keep in mind the performance, etc., and realistic use cases

@Skillmon I'd welcome a PR (I might look myself, of course)

@DavidCarlisle Ohh, now linking to your tool.

@JosephWright well, the default arguments are already implemented for built ins. Variadic functions seems to be just another step for it, and is possible via tuples, I guess. E.g., one could program a polyval(<x>, (<coeffs>)) function.

@JosephWright what could be nice were user-level documented asserts (for instance \fp_assert_is_tuple:n {#2} for above's polyval), and user-level documented methods to access a tuple (or use clist for that).

@mickep :-)

@Skillmon I think first we'd need agreement on integrating the current code - there was some talk about it a while ago, but we might get traction now

@JosephWright the only thing that's "hard" is then key=value (and I can use expkv-cs for that to be fast, depending on the number of needed keys).

@JosephWright fpeval user-defined function would be a really useful addition. I find myself using the pgf declare function quite a lot, but the lack of precision (and range) is very dangerous (yes, I know about pgfmath-xfp, very useful).

@Skillmon Well keyval_parse can do that, so it's a build-in

@Rmano I'll raise with the team again (perhaps today)

@JosephWright yes, of course, but \keyval_parse:nnn does no expandable argument reordering to access specific values. And I doubt you want to work with flags etc.

@JosephWright you could, however, implement a expkv-cs similar function using \keyval_parse:nnn and a few hand-made auxiliary macros.

@Skillmon Yes, but if we want to say it's supported in expl3, then it needs to work with the built-in tools

@JosephWright of course :P And as I said, one could implement it rather easily in expl3 though doing this manually for a couple of functions might get tedious:

\cs_new:Npn \__my_flag:n #1
  {
    \cs_if_exist_use:cF { __my_flag_#1: }
      { \msg_expandable_error:nnn { my } {unknown-flag} {#1} }
  }
\cs_new:Npn \__my_arg:nn #1#2
  {
    \cs_if_exist_use:cTF { __my_arg_#1:n }
      { {#2} }
      { \msg_expandable_error:nnn { my } {unknown-arg} {#1} }
  }
\cs_new:Npn \__my_arg_round:n #1 #2 \__my_arg_round:n #3
  { #2 \__my_arg_round:n {#1} }
\cs_new:Npn \__my_flag_inverse: #1 \__my_flag_inverse: #2
  { #1 \__my_flag_inverse: \c_true_bool }

\cs_new:Npn \__my_function:n #1

@Skillmon Could be wrapped up if it's useful - first we should sort the general point

@JosephWright nothing special, preparing TUG?

@UlrikeFischer Yes, that was my #1 - I'll circulate something at lunch time

@JosephWright ooh maybe the lunch

@PauloCereda did someone say "lunch" ?

@DavidCarlisle oh no

This guy deserves a medal:

@egreg @CarLaTeX ^^ :)

@PauloCereda Great sense of geometry! (Note that, in Italian, peperoni (with one "p") means peppers, the vegetables)

@CarLaTeX ooh

@PauloCereda The pizza in the photo is "al salame piccante"

@CarLaTeX aha

Now it makes sense :)

@PauloCereda Pay attention when you order a pepperoni pizza in Italy!

@CarLaTeX hopefully they will have menus with photos. :) And I will probably order a Romana. :)

@PauloCereda Good!

Train stops in Verona. I better wave to egreg.

@mickep ooh

@JasperHabicht ooh looking forward to meeting you at TUG!

@PauloCereda Oh, you leaked it =D Yes, I decided to register, but only for Saturday. Really looking forward to it.

@JasperHabicht we ducks are very good at keeping secrets :)

@JasperHabicht Nice!

@PauloCereda revealing* kkkkkkkkkk

@mickep oh no

@PhelypeOleinik ^^ the dodo bloke found out about the Brazilian kkkkk

@PauloCereda dodos have their secret channels...

@mickep ooh

@PauloCereda Dodos are smart, no wonder they are de-extinguishing themselves

or something like that :)

@PhelypeOleinik hahaha (as we write here...)

@PhelypeOleinik ooh smart birds

@JosephWright I would be happy to help in any capacity for which I'm competent.

@UlrikeFischer skype secrets. :)

@DavidCarlisle ooh

@CarLaTeX -- I gather that peperoni and peperoncini are not the same?

@Rmano -- Here in Rhode Island (with a substantial Italian population), peperoncini are a somewhat larger pepper, but long and thin and hot, as opposed to round and sweet (bell peppers). The "local" peperoncini are usually harvested before they're mature, and aren't as hot as they might be. They're often pickled. I can enjoy them in small quantities; really hot peppers make my mouth blister, which makes any eating unpleasant for the next few days. So I wanted to know what's "real" Italian.

@barbarabeeton ^^^ peperoni

@barbarabeeton ^^^ peperoncini

@CarLaTeX Not to scale. :)

@AlanMunn I did what I could :D

@CarLaTeX -- Ah! Bell peppers! Thanks. (Pretty too.) And the others are dangerous.

@barbarabeeton Our house is very dangerous then.

@barbarabeeton They are spicy, but they are vasodilators, so they're good for the heart

@CarLaTeX there is a nice farm in Tuscany that grows lots of different varieties of "pepperoncini piccanti", and they have a nice scale from 1 to 16 or whatever for oils or paste or similar preparations.

@AlanMunn -- I once made chili con care with fresh pasilla chili, cooked it in a cast iron dutch oven. Big mistake -- The whole inside of the pot was covered with fresh rust when time came to open it. Nobody could eat it, although I did manage to salvage and reseason the pot.

@barbarabeeton Carolina Reaper must be harvested with gloves and safety glasses --- I have a 10% diluted oil, and we use it with a dripper we bought in a pharmacy ;-)

@CarLaTeX -- I'm sure that's true, and I'm just a wimp. But I don't like eating to become painful for days at a time. It's hard to apply burn ointment to one's lips and tongue.

@Rmano -- Ouch! The sad thing is, the darn things often have really interesting flavors.

@Rmano ooh

@Rmano no rocoto pepper? :)

@barbarabeeton yes, carolina reaper do have a nice flavor. Although I really like Scotch Bonnet

@Rmano Wow

@PauloCereda I don't know it... but then, there are thousands of types of peppers...

@Rmano indeed! Aji has a lovely name here in Brazil: dedo-de-moça (literally, lady's finger)

Why didn’t the green pepper get into archery? He didn’t Habanero. /ba dum tss

@Rmano -- They are pretty! But it's safer for me if I keep the Scoville units below a hundred. (Who was Scoville anyhow?)

@barbarabeeton Ooohhh, I think they weren't cooked well or not in the right doses if they had such consequences!

@barbarabeeton we could order pizza while in Bonn and make @CarLaTeX and @egreg nervous with some interesting toppings. :)

@PauloCereda Impossible, I'm sure all pizzerie in Bonn are Italian :D

I've never really seen the appeal of the super hot varieties. I've tried them occasionally, but they add more heat than flavour in my experience, so I'm happy to stick with more of the slightly less hot varieties. The ones we always have in the kitchen are Bird's Eye and Fresno peppers.

@CarLaTeX ooh so Bonn people are pizza aficionadoughs. /ba dum tss

Wow! Thunderstorms have just swept in. Very noisy with bright flashes. Actually noisier than the fireworks a couple of days ago. And closer ...

@PauloCereda Well, then: Bonn appétit!

I also heard aardvarks like ant-chovies on their pizza. /ba dum tss

@JasperHabicht <3

@AlanMunn I never tried Bird's Eye, but they say it's around 100k Scoville, more or less like Scotch Bonnet... (Carolina Reaper is 2M)

@Rmano They can be quite hot for sure. I like them because they freeze well so I always have a bag of them in the freezer.

@AlanMunn Ah, ok, I've seen it. It's quite common, the problem is that it's normally just called "peperoncino"... I like it, especially if you can find it fresh (here it's basically dried), but yes, it's stingy

@Rmano If you have any East Asian (especially Thai or Vietnamese) groceries, they will likely have fresh ones.

@PauloCereda There's a big river in Bonn…

@egreg oh no

What would be the expl3 equivalent of doing this:

\newcommand\foo[1]{\bar#1}
\def\bar#1:#2{\textbf{#1}:\textit{#2}}

@AlanMunn This is wrong code. If you call it \foo{a:bc} you only get b in italics.

@egreg I don't care about what happens inside. That was just for demonstration. How would I get a command with syntax \foo{A:B}

@AlanMunn There's also the “little” complication that the colon is catcode 11 in expl3 code.

@AlanMunn does it have to be a colon?

@AlanMunn Seems like egreg wrote about this in 2020: tug.org/TUGboat/tb41-3/tb129gregorio-l3functions.pdf (p 304 or so)

@UlrikeFischer Well, I like colons, but I could be persuaded otherwise. :)

@AlanMunn VVV

\documentclass{article}

\ExplSyntaxOn

\NewDocumentCommand{\foo}{m}{ \munn_foo:n { #1 } }
\cs_new_protected:Nn \munn_foo:n
 {
  \__munn_foo_aux:w #1 \q_stop
 }
\use:e
 { % the "little" complication
  \cs_new_protected:Npn \exp_not:N \__munn_foo_aux:w #1 \c_colon_str #2 \exp_not:N \q_stop
 }
 {
  \textbf{#1}:\textit{#2}
 }
\ExplSyntaxOff

\begin{document}

\foo{A:B}

\foo{ABC:DEF}

\end{document}

@AlanMunn well colons are sometimes a bit hard: tex.stackexchange.com/questions/302387/…

@PauloCereda Well, in Venice it's much easier to slip, but… :-D

@egreg ooh

@AlanMunn my version is much simpler than @egreg's

\ExplSyntaxOff
\newcommand\foo[1]{\bar#1}
\def\bar#1:#2{\textbf{#1}:\textit{#2}}
\ExplSyntaxOn

@egreg Brazil has slightly larger rivers ;-)

@UlrikeFischer and giant snakes :)

@DavidCarlisle ooh expl3 skills

@egreg I can see that it works, but I definitely don't understand how.

@AlanMunn it is this, more or less:

\newcommand\foo[1]{\bar#1\relax}
\expanded{\def\noexpand\bar#1\string:#2}\relax{\textbf{#1}:\textit{#2}}

@AlanMunn the \expanded makes sure you get a catcode 12 : delimiter

@DavidCarlisle Ok so if I didn't need the colon the code could be simplified

@AlanMunn yes you could lose the \use:e If you do want : my original suggestion of locally turning off expl3 is not totally in jest

@DavidCarlisle Yeah, I can see that!

@DavidCarlisle ooh plot twist

@AlanMunn Are you trying to learn about expl3?

@FaheemMitha Yes. It's so much easier to do many things, but there's still lots to learn. And my understanding of TeX itself is patchy, but that knowledge is still somewhat required to use expl3.

@AlanMunn Are you trying to use Lua as a backend as well?

@FaheemMitha No I have no need for that. I mean, I use luatex as my main engine, but I don't ever need actual lua code for anything I do

@AlanMunn OK. But sometimes Lua code can substitute for TeX code. And when it does, it's far simpler.

I don't know if expl3 makes TeX programming easier. My understanding is that one of its main purposes is to present a consistent programming interface. But it still seems quite complicated, because it does not hide the internal complexities any more than the traditional programming techniques did.

@FaheemMitha Just providing a rich array of built-in data structures and methods for manipulating them is huge improvement.

@FaheemMitha it's a lot easier as it provides libraries of pre-written code, lists, loops, regex, floating point, ....

@AlanMunn Built-in data structures? Really? Huh.

@FaheemMitha In LaTeX, the substitution from Lua is really not worth it most of the time. In contrast to ConTeXt where it's a pleasure to use ConTeXt's interface from Lua. expl3 feels much more integrated in the LaTeX world and that's a huge value in itself.

@FaheemMitha lua code might be easier if you are more used to that kind of language, but getting results between lua and tex exposes very low level tex details you can not ignore

@FaheemMitha Yes, sure, have you had a look at the table of contents of interface3.pdf?

@TeXnician I've glanced at it.

@TeXnician For small bits of code, agreed, it isn't.

@DavidCarlisle I still hope for a LaTeX-Lua interface like ConTeXt has one day. Then you can ignore those low-level TeX details ;)

@TeXnician tricky to commit to closer binding to lua while supporting xe/pdf/p/up tex

@DavidCarlisle Well, you should know that \use:e is exactly the same as \expanded.

@egreg yes that's what I explained to @AlanMunn

@DavidCarlisle I know. And providing Lua interfaces nevertheless which would only be available in LuaTeX would lead to a divergence which makes it hard to maintain. Unfortunate, but understandable.

@UlrikeFischer And there are piranhas

@UlrikeFischer You don't have them in the Rhine, do you?

@egreg just ducks:

@egreg Actually, I read that people sometimes seem to catch some in smaller rivers that flow into the Rhine ...

Learned a new word: tributary

@TeXnician Using using Lua with ConTeXt easier because ConTeXt is now mostly written in Lua itself? Or for some other reason?

@JasperHabicht That's one of those words whose meaning has changed dramatically. It used to mean protection money. Like in the Mafia.

I suppose that's still technically one of its meaning, but now rarely used except in a historical context, I suppose.

@FaheemMitha Wow, I had no idea it had such meaning. I've never encountered it in that usage, only the 'offshoot of a river' meaning.

@AlanMunn Is that sarcasm? :-)

@FaheemMitha No, seriously. Looking it up, there's plenty of uses in Shakespeare, so I probably have encountered it at some point, but that meaning is not one I know at all.

@AlanMunn Oh, I just assumed you were being sarcastic. I'm glad you're not.

It's an old Roman word. It appears in "Julius Caesar", for example, right at the beginning. The Shakespeare play, that is.

It was the Romans' polite word for robbing someone. The original hypocrites. It probably says something about my mind that it's the first meaning I think of when I see that word.

@FaheemMitha So kind of like what Americans think 'tax' means. :)

@AlanMunn Well, taxes are supposedly used for the betterment of the populace. But yes.

I am referring, of course, to the Marcellus speech in Act 1 Scene 1.

I "studied" JS in school. Unless most things I've studied, I retain a somewhat positive view of it. Also, I've always been somewhat interested in that dynasty.

@FaheemMitha Clearly your memory for Shakespeare exceeds mine!

@AlanMunn I just remembered that bit. But like I said, I have a positive view of the play. We also did "The Merchant of Venice" and "As you Like It".

@AlanMunn So has your usage of expl3 been positive so far?

@FaheemMitha A very traditional colonial schooling it seems. We read Julius Caesar, Macbeth, Hamlet, King Lear and the Merchant of Venice. I don't remember ever reading the comedies in school.

@FaheemMitha Yes, I wrote one package using it, and am quite pleased. So going forward I'll probably adopt it for other packages I write.

@AlanMunn Indeed, yes. A vestige of the Raj. Though that was in the early 1980s.

@AlanMunn OK, good to know. Thank you.

@FaheemMitha -- I'm familiar with the money connection, but in the form "tribute". "Tributary" is clearly related, but as a noun, it's usually used these days to denote a waterway that flows into a bigger waterway. And both are related to "contribute", but that is usually considered to be free of coercion. I think you may be thinking of the quote "Millions for defense, but not one cent for tribute." (Unfortunately, I've forgotten who said that.)

@AlanMunn -- Not all Americans, please. I'm willing to help support reasonable community services, although I would be happier if I had more say in what the funds are used for. (When I slipped on the ice a few year ago, I was sure pleased that a competent ambulance crew from the fire department was right there to rescue me, and since we pay our city property tax, there was no bill.)