00:00 - 21:0021:00 - 00:00

12:04 AM
!!/battle
@PauloCereda Psmith, the TeX bot: The current score is egreg 0 vs. 0 David. So far, nobody is winning today.
!!/battle
@PauloCereda Psmith, the TeX bot: The current score is egreg 20 vs. 30 David. So far, David is winning.
ooh!
@egreg: ^^

@PauloCereda quite right too. I assume that's 5 of your votes unevenly distributed between us?

@DavidCarlisle I'm getting started. :)

@PauloCereda well don't give any rep to that other bloke

Hey guys, I just had a quick question about the geometry package. I need to tweak the following code \geometry{
paperheight=8.00in,
top=.75in,
bottom=.75in,
paperwidth=5.25in,
inner=.38in,
outer=.75in,
bindingoffset=.75in,
} For it to contain inside margin of .75in and outside margin of .5in. How can I do that?

@DavidCarlisle :)

12:14 AM
@gekkostate don't you just change inner and outer to the values you stated (not that I've ever used the package really:-)

@DavidCarlisle But then what do I do with the other settings? Do I comment them out?
@DavidCarlisle I have just received a proof of my book and the margins from the right side of the page is too in.

@gekkostate well they all refer to things you didn't say you wanted to change: paper... is the physical paper size, top and bottom are the top and bottom margins... so you need to set them to whatever you need

@DavidCarlisle What is bindingooffset?

@gekkostate it depends (for a book it all depends:-) in particular are you supposed to make the thing with the specified margin to the physical edge of the paper or to crop marks that they will cut to during the binding process. Not that I've ever looked at the geometry package doc but I assume it's extra space on the inner edge (in addition to the inner margin) that is assumed to be lost in the process of binding the book together

@DavidCarlisle Ahh, I see what you mean for bindingoffset. It makes sense. This is what I am referring to as a resource. createspace.com/Products/Book/InteriorPDF.jsp

12:21 AM
@gekkostate see texdoc geometry figure 6 (see it does have a manual after all:-)

12:31 AM
!!/battle

@DavidCarlisle Psmith, the TeX bot: The current score is egreg 30 vs. 100 David. So far, David is winning.
!!/battle
@PauloCereda Psmith, the TeX bot: The current score is egreg 60 vs. 110 David. So far, David is winning.

@PauloCereda on which happy note: time for bed...

@DavidCarlisle Good night, David. :)

4 hours later…
4:15 AM
@Bugbusters are you done with pstricks tutorial ? BTW did you use asymptote for your work ?

@texenthusiast Not yet. I am working for my homework first.
I don't use Aysmptote.

@Bugbusters asymptote syntax is similar to PST ?

@texenthusiast No. Asymptote syntax is similar to c language.

@Bugbusters ok carry on thanks :)
@Bugbusters i was wondering why @g.kov did not make an ameoba in .asy. it should be possible right ?

@texenthusiast it is possible.

4:26 AM
@Bugbusters ok connecting rand points in rectangular domain is the trick. its a good excercise. Bye then :) take care

@texenthusiast :-)

5:08 AM
@Bugbusters did you asy see

@texenthusiast yes. long time ago.

@Bugbusters its recent '12, i dont know when you saw , @g.kov may write an answer for your Q

5:50 AM
hi there!
if I may barge in with a non-Cricket-results-related question
regarding a question
the question is quite popular, but the answers have some overlap but no coherent comparsion of the pros & cons of the different techniques proffered
minipage, subfig & subfloat, \quad (?), parbox, subcaption & subtable
is there a consensus of what's considered best, if both "subtables" also have captions (but without the "Table 2.1"-bit)
As the chat seems to have gone back to sleep, I just posted this as a comment to the original question, for want of a better place place to put it

6:59 AM
1

Can anyone help me find a suitable latex software that already includes an editor. I tried downloading MikeTex but it tells me to download an editor which I am not familiar with. I am not a hardcore latex user; I just want to use it while doing some notes and other miscellaneous things. What are ...

I'm voting to reopen this question, since IDEs are not the only solution to the qners problem, but the online Latex editors work as well.

7:35 AM
Having 'fun' reinstalling MacTeX: luckily the DVD version and the 'plain TeX Live' installer option have worked

@CharlesStewart The question is specifically about downloads. Not only the title, it also ends with "What are the easiest downloads for LaTex?". Since online editors cannot be downloaded, no need to reopen I think.

@StefanKottwitz The OP seems to want something like MathJaX: I wonder if they want to use it in a word processor

I'm travelling to São Paulo in a few minutes, so you guys behvave while I'm gone. :) I'll be back in the evening, hopefully. :) Cherrio!

@PauloCereda Have a good trip!

Heya!

8:05 AM
@StefanKottwitz This is an XY-question: the qner asks for downloads, but the problem is the difficulty he/she has with getting a useful Latex setup in place ("I am not a hardcore latex user; I just want to use it while doing some notes and other miscellaneous things. "). The online services seem to directly address that problem, and I'm pretty sure an answer pointing to these services would generally be regarded as on topic.

@JosephWright How can I set the remainder value to variable?
\tl_set:Nx \remainder \int_mod:nn {10} {3}

This gives an error

@user4035 It will do, you've not got any braces
\tl_set:Nx \remainder { \int_mod:nn {10} {3} }
but really this looks like an integer variable
\int_set:Nn \remainder { \int_mod:nn {10} {3} }

@JosephWright worked, thx

8:27 AM
@CharlesStewart Did the OP confirm that online compiling instead of downloading would solve his question too? I did not see it in the comments. If he doesn't have permanent internet access and therefore asked for downloads, guessing the online way and answering that wouldn't be much helpful.
@CharlesStewart Also, it would be just another duplicate to the online editing question.
@CharlesStewart You already provided that information to the OP via the comment, great.
@CharlesStewart Now, that the OP got the help ne needed, also the pointer to online services, the question remains: is it useful for the site, for future users, to reopen the question, if we have comprehensively answered duplicates already?

8:50 AM
@nuttyaboutnatty Oh no @PauloCereda's travelling, so Psmith is gone you'll have to wait for the cricket results.

9:11 AM
I found an incorrect statement in amsmath.pdf page 3 as follows.
As the following is contradictory to the above statement.
\documentclass{article}
\usepackage{amsmath}
\begin{document}
\begin{multline}
\framebox[3cm]{Row 1}\\
\begin{split}
\framebox[2cm]{Row 2}
&= \framebox[2cm]{Row 3}\\
&= \framebox[3cm]{Row 4}
\end{split}\\
\framebox[4cm]{Row 5}
\end{multline}
\end{document}

@JosephWright does this look like a siunitx/l3 version mismatch to you? tex.stackexchange.com/questions/109339/…

@Bugbusters I get the following warning:
Package amsmath Warning: Cannot use split' here;
(amsmath)                trying to recover with aligned' on input line 12.
@Bugbusters The recovering is successful, but this doesn't contradict the manual.

@egreg So what does the word "cannot" mean?

@Bugbusters That it can't be used in multline, because the result is unpredictable: recovering can be successful, but it's not guaranteed.

@Bugbusters It means you should not do it and get told off if you do.

9:30 AM
@egreg, @DavidCarlisle: Thanks!

@nuttyaboutnatty well check if it works without siunitx then if that's the case we can look at how to make it work with. The system is getting cross with the comment thread, I pinged Joseph iabove but he's not around

10:04 AM
@DavidCarlisle Yes

10:15 AM
@DavidCarlisle tried to avoid siunitx here paste.ubuntu.com/5718337 but still get an error
Package caption Error: Something's wrong--perhaps a missing \caption (caption) in the last figure or table. See the caption package documentation for explanation.
(which is the same error in the comment @ tex.stackexchange.com/questions/109339/…)

10:38 AM
(got rid of the { } braces in some cells)
@JosephWright I don't know what a "siunitx/l3 version mismatch" is; is there any way to avoid it and to make this thing tex.stackexchange.com/questions/109339/… work?

@nuttyaboutnatty siunitx uses the LaTeX3 code in l3kernel and l3packages. As we fix bugs and add new features quite regularly, siunitx versions are 'tied' to the matching versions of l3kernel and l3packages. The standard advice is to update to the latest version of all of them using your package manager: I release only 'matching' code.

@JosephWright hmm, I use this ppa launchpad.net/~texlive-backports/+archive/ppa and wouldn't know how to become more up-to-date (at least not via a ppa)
is there no other workaround?

11:00 AM
4
A nice number today. :)

11:13 AM
@PauloCereda My dumbphone is not, fortunately ;)

@nuttyaboutnatty They should be 'matching'. Can you try a minimal example
\listfiles
\documentclass{article}
\usepackage{siunitx}
\begin{document}
\end{document}
and report on any errors

(no errors ?)

@nuttyaboutnatty With a fully up-to-date TeX Live it all works, so I'm afraid this is likely to be a fixed bug. There was an awkward one in l3kernel a while ago.

:(
@JosephWright are you on Linux?

@nuttyaboutnatty You are probably best grabbing l3kernel.tds.zip, l3packages.tds.zip and siunitx.tds.zip from CTAN and doing a local install

11:27 AM
fully up-to-date meaning beta or alpha release?

@nuttyaboutnatty Not routinely: Mac at home, Windows at work
@nuttyaboutnatty Meaning fully up to date :-)
@nuttyaboutnatty It's virtually impossible to get packages tested before sending to CTAN

hmm
I think for now I'll just leave it as two separate narrow neat tables
unless you'd recommend the subfig package as a viable / good alternative to the subcaption pkg ?

6
...from the new tikzmark addition to CTAN. Thanks @AndrewStacey. :)

@Werner Are you saying "Thanks" because I didn't list you there?

11:56 AM
@AndrewStacey No, not at all. I don't think I've ever used \tikzmark. My use of tikz is lacking... I'm saying thanks for the entertainment of acknowledging @DavidCarlisle. After all, he has the bronze tikz-pgf badge, and closing in on silver.

12:10 PM
Any native speaker here? Please, compound surnames: dash or hyphen?

Any desktop environment suggestion for Ubuntu 12.10?

@tohecz Native speaker in ?

@Kurt \newcommand*\nativespeaker[1][English]{#1} ;)

@tohecz Well with German I would be able to help you :(

@tohecz Single surname is hyphen: Smith-Jones proved a result. Two names is a dash: The Atiyah--Singer index theorem.
@Werner I got one hit when searching for you and tikzmark.

12:35 PM
@AndrewStacey oi:-)
@tohecz hyphen usually

@DavidCarlisle ok thanks
@AndrewStacey btw, I've got my tasty fruit pie recently ;)

12:52 PM
@tohecz Now you can eat toast.

@kan Hi :) use the default or change the distro, you prefer rpm or deb

@AndrewStacey or connect to the internet (once I get the GPRS dongle)

1:27 PM
hello, can I know what are the default font sizes for something like \chapter{new}
?

1:40 PM
21

In the preamble I have: \documentclass[a4paper,11pt]{article} \usepackage{fontspec} \setmainfont{Arial} What can be inferred about the real font pt size for the following? \tiny, \scriptsize, \footnotesize, \small, \normalsize, \large, \Large, \LARGE, \huge, \Huge

@Rick_2047 For the standard classes, chapter is \huge; section is \Large; subsection is \large

hmm.. my requirements do not fall in this categories
i need to set them as custom

@Rick_2047 So use the titlesec package to do this.

this is the formatting that I want
@AlanMunn looking into that

15

Warning If you're looking for advice how to make your document look like it's been written in Word, this is most likely not the question you're looking for. This question is mostly of theoretical nature, as it results in tiny differences, which will most likely not be noticed by someone who does...

(This question has lots of links to relevant answers.)

@AlanMunn thanks for this, got some reading to do

1:48 PM
@Rick_2047 Those requirements aren't too bad. Use the geometry package for margins, titlesec for headings, setspace for line spacing, caption for formatting table/figure captions and you're done. :)

yeah, I think so too
just trying to figure out how to capitalize all the chapter names automatically

@Rick_2047 search the manual of titlesec for \MakeUppercase

2:19 PM
@AlanMunn Superpalindromic!

2:30 PM
@egreg but far from being primitive

i am using setkomafont and want to insert a horizontal line just after the chapter name, how will Ido that?

@Rick_2047 You cannot do that with \setkomafont, but you can do it with titlesec.

The popular UK-TUG course is on again this year: uk.tug.org/2013/04/18/…
3

@egreg Indeed.

2:42 PM
@TorbjørnT. then I will have to use titlesec

@TorbjørnT. I don't use KOMA, but doesn't it have methods equivalent to titlesec built in?

@AlanMunn Not entirely sure actually.

@TorbjørnT. Me neither. I don't want to spread misinformation, so I'll shut up.

3:11 PM
@DavidCarlisle ping marco
PING marco (000.000.00.001): 56 data bytes
64 bytes from 000.000.00.001: icmp_seq=0 ttl=54 time=1 hour

@Rick_2047 There seems to be some incompatibilities between the KOMA classes and titlesec: tex.stackexchange.com/q/36299/3954 (since most or all of texts in the links are in German, I really haven't read them so I cannot tell what the problems are).

Any ideas?
Thanks, but this produces errors when I use underscores in \label{}. How can I fix this? — Foo Bar 6 hours ago

@MarcoDaniel Depends on other packages loaded

@JosephWright is there a way for me to search my deleted answers? Do they appear listed somewhere?

@MarcoDaniel don't put underscores in label is the best solution
@MarcoDaniel ping (are there documented restrictions re footnotes, never looked at the doc:-)

3:23 PM
@DavidCarlisle Indeed ;-)

@MarcoDaniel I added a comment

@tohecz Thanks.
The chat has a new favicon ;-(

@MarcoDaniel although in that case you should make _ catcode 12 rather than 13 and give it mathcode "8000 then it will only be active in math so be allright in label.

@DavidCarlisle Good idea. I will add this.

@MarcoDaniel You edited Frank's answer but you didn't admit that \footnote doesn't work in this case:-)

3:28 PM
@DavidCarlisle :-)
I wrote a small comment
@DavidCarlisle I don't need to set \catcode_=12 It works without:
\documentclass{article}
\usepackage{fouriernc}

\begin{document}
$a_1$

$a_{\!1}$

\makeatletter
% \catcode\_=12
\mathcode\_="8000
\def\_#1{\sb{\!#1}}
\makeatother
$a_{1}$
$$1+1=1\label{eq_1}$$
Text \ref{eq_1} Text$_1$
\end{document}

3:45 PM
@JosephWright will they be video recorded ? and uploaded online at uktug to benefit people not present , are there any old ones here

@DavidCarlisle: for you
0

The command \catcode is often used to change some internals. E.g. the command \makeatletter changes the catcode @. But what is \mathcode and how does it work? catcodes are well explained here: Wiki TeX catcode

@texenthusiast I'll see what I can do. The practical course doesn't lend itself quite in the same way to being recorded, but it might come off. I'll ask the committee about getting a proper microphone.
@texenthusiast There are currently only recordings for last year's meeting as it's the first time I've done that

@JosephWright thanks for info and first time recordings. is your talk in france video recorded by gutenberg ?

@texenthusiast I'll have to ask them: again, if it's not I'll arrange to self-record on my Mac (I've now got a good idea how to do it)

wow, I've got a Notable Question badge for a question with no Nice Question badge...

3:51 PM
@JosephWright thanks for all. i wish i was there but could not so asked for it

@texenthusiast I'll consult: doing the recording is quite easy if you go for slides + sound
Thanks to instructions from @PauloCereda

@tohecz In the vein of this something can be notable without being nice. :) (Although perhaps that's the difference between 'notable' and 'notorious'.)

@JosephWright do you mean this

@AlanMunn the name "Notorious" would suit the badge better, but it sounds too negative IMHO :-/ (like a notorious drinker)

@texenthusiast The Vimeo videos were done using iMovie to combine the slides with recordings made using Audacity

3:55 PM
@tohecz Or Notorious B.I.G.

@GonzaloMedina ?

@tohecz Right, that's why it works for the not nice questions!

@tohecz Nevermind. Better if you don't know who that is.

@GonzaloMedina LOL

@JosephWright an idea to have a meta Q to help others as well

3:59 PM
@texenthusiast Not really about the site

@JosephWright where is it appropriate for many tex talks then ?

@GonzaloMedina holy silliness :)

@MarcoDaniel next question will be about \delcode?

@texenthusiast Do you mean a list of videos?

@GonzaloMedina First time I read \delcode;-)

4:02 PM
@MarcoDaniel So the answer to my question is "yes" ;-)

@GonzaloMedina LOL

@JosephWright nope workflow for video and may be a list of links

@texenthusiast Workflow for making videos has nothing to do with TeX, so SuperUser or something

@JosephWright this.

@GonzaloMedina I expanded my question ;-)

4:08 PM
@MarcoDaniel well if you leave it at 13 then the mathcode isn't used. Oh I see you have a qn (I was working on the day job:-)

@DavidCarlisle I know this problem :-)
Can somebody test the following example please?
% arara: pdflatex
% arara: biber
% arara: pdflatex
% arara: pdflatex

\documentclass{article}
\usepackage[style=alphabetic,maxbibnames=99]{biblatex}

\DeclareLabelalphaTemplate{
\labelelement{
\field[strwidth=4,strside=left,names=1,lowercase]{labelname}
}
\labelelement{
\literal{~}
}
\labelelement{
\field[strwidth=2,strside=right]{year}
}
}
\begin{document}
\cite{companion}
\printbibliography
\end{document}

Mathematically Correct Breakfast: youtube.com/watch?v=dN8AwGUaqDA

@JosephWright ok understand :) why new we have related

@DavidCarlisle And what about \delcode in your answer? ;-)

@GonzaloMedina Indeed

4:23 PM
@GonzaloMedina i'm typing...... (it's there now:-) @MarcoDaniel

@DavidCarlisle I am reading

@MarcoDaniel I just edited it a bit more to make it closer to an approximation of English

@DavidCarlisle and an approximation of German?
:-)

@MarcoDaniel s/ //g
@MarcoDaniel I see you tagged it as latex-kernel but I gave a plain tex answer (as latex abstracts things away from mathcode more or less) I wonder if I should retag it as tex-core?
@egreg yes will add, Funny really as before the question I'd just made that exact comment here that _ could be made catcode 12 and mathcode "8000 instead of being catcode 13

4:42 PM
@DavidCarlisle I didn't know where it comes from.

@MarcoDaniel well for latex I'd have to describe \DeclareMathSymbol{+}{\mathbin}{operators}{"2B} which is sort of the same as \mathcode\+="202B but different:-)

@DavidCarlisle It would be a great addition ;-)

@MarcoDaniel perhaps this evening (.NET calls)

@DavidCarlisle Thanks.

5:29 PM
@AndrewStacey I see that tikzmark made it to CTAN. Congratulations! Now I can officially abuse it :-)

@AndrewStacey Wow, I got a somewhat undeserved mention! Thank you but more importantly thank you for making it an awesome tool out of a one-liner
The thesis is almost done so I can start doing simple matrix computations ;)

Can someone point me to the difference between the different but similar \\ and \newline? Thanks.

@FaheemMitha is main site Q ok ?

@FaheemMitha Not that I know deeply but do you mean in a straightforward text on the page? \\ is context-dependent

@texenthusiast Excellent, thanks.

5:43 PM
29

What is the difference between \par and \\ and when should I use \par instead of \\?

@percusse No specific question. Just which you should use, and when, I guess.

@FaheemMitha Never use them except in the tabular stuff is a pretty close approximation :)

@percusse Hmm. Yes, I noticed that \\ seems rather more breakable. So generally prefer \newline then?

@FaheemMitha pages 51 and 52 of source2e for the "initial" definitions. Depending on the context in which they are used, they might be equivalent

Is there a short form of \newline?

5:46 PM
@FaheemMitha No I mean don't use them at all. You would need them very rarely. Leave an empty line for line breaks.

@percusse I tend to disagree with this. I know that sometimes \\ is abused, but when you know how to use it, it can be very handy.

@GonzaloMedina True but it's very rare don't you think?

@percusse An empty line is not equivalent to a new line, is it?
Doesn't it force an indent?

@percusse But this starts a new paragraph. What if you want to start a new line inside a paragraph?

@FaheemMitha That's why I asked the context. Depends on where you use them.

5:48 PM
@percusse Well, I'm currently sprinkling lots of \newlines in a set of corrections I'm writing, to force line breaks where the typesetters (who are not using TeX, poor benighted things) are putting them. I noticed that \newline always works, but sometimes \\ doesn't.

Before, I should have said "ends the current paragraph"....
But, since no one is paying attention to what I say, it doesn't matter :-)

@GonzaloMedina \usepackage{parskip} ;-)

@percusse What does parskip has to do with what I said? That package just sets \parindent to 0 and increases \parskip.

@GonzaloMedina I am.

@GonzaloMedina If you want to start a new line inside the paragraph it's a nonindented paragraph no? It's a joke by the way :)
@GonzaloMedina To be honest, I have never did that until you said it. Is there any typographical case where you need newlines without starting new paragraphs?

5:55 PM
@percusse I just gave one.

@percusse I find this kind of construction very often:
\documentclass{article}

\begin{document}

\noindent Name:\\
ID Number:\\
Course:

\end{document}
I know that a tabular could be used, but for such simple case, I would think it's unnecessary.

@GonzaloMedina \facepalm
Indeed I've never used it like that. I always put it inside a tabular thanks to autocomplete.

@GonzaloMedina I often do that as well.

@percusse But then \begin{tabular}{@{}l@{}}...\end{tabular} is too long to write.
@percusse Ah, you use autocomplete.

@percusse No. There may be some particular case in which a newline is good, but it's a rare exception rather than a rule. @FaheemMitha's example is one, but it's surely not a general construct. It's a "one shot" trick.

6:08 PM
\documentclass{article}
\begin{document}
{\setlength{\parindent}{0pt}
Name:

ID Number:

Course:
}
\end{document}
@egreg I don't understand the example to be honest
but today I can say anything as the whole day I kept blundering.

@egreg: Why was it wrong?

@egreg Do you happen to remember a question asking for some decorations (horizontal rules with some vertical rules at the ends) for an environment? I deleted my answer since it didn't guaranteed no page breaks before the last rule. Now I've found a way to prevent it, and I'd like to answer the question. Problem is I cannot find it!

6:38 PM
@GonzaloMedina Do you know the importance level of Marginpar on page ## moved by ##.# pt.? I don't know if that would be a valid addition to the warning question. I sometimes identify the cause sometimes not. Should I edit the question and that?
We also have
22

I repeatedly get the LaTeX warning: LaTeX Warning: Marginpar on page x moved. What does this mean? Is that a problem? How can I fix the corresponding problem?

One more LuaTeX question for the silver badge!

Can be closed as TL -- see last comment
@MarcoDaniel Yes, the basic customized settings for my case can be found in tex.stackexchange.com/questions/12806/… and if I run into some problems with this I will open a new question. Let's close this. Thanks again:-) — Shea 2 mins ago

@PauloCereda Here's another one :) github.com/navarroj

@percusse Sorry, for not answering before. This happens when a \marginpar couldn't be placed in line with the text line in which it was declared (typically because another \marginpar took some of its space).

@GonzaloMedina Indeed that's the general reason but for example at each chapter title page, I have chapter numbers located in the margin and each of them causes one warning which are 30-40 pages apart from each other. Maybe it's a memoir specific problem.

6:56 PM
@percusse Could you give a mock-up document showing this effect? I mean, if it's not to time consuming to design one.

@GonzaloMedina That's actually what I was doing :) But MWE loses the problem. I'll try to isolate the cause first. It's a longish .sty file.

Most strange thing just happened. Suddenly I got disconnected from the site and when I logged-in again, a scary button "Destroying credentials" appeared and some warning message about the consequences of destroying the credentials.

@GonzaloMedina ??

@percusse No idea. First time. Of course, I didn't dare to Destroy my Credentials (whatever they are; I din't take the time to read the full message).

@GonzaloMedina There is a MSO question maybe about that.
4

I've occasionally used my sister's computer to visit stackexchange sites, including the chat on EL&U. This was all well and good, except that tonight, my sister decided she wanted to join the fun and get an account of her own. Well, let's just say that "not fun" (and "not easy") don't even begi...

I don't know where that button is

7:17 PM
Still don't know what happened (or why) and why that button appeared.

@FaheemMitha \newline is defined to use the internal version of \\  without the optional argument lookup. But if you are using either you're doing t wrong:-)

@DavidCarlisle doing t wrong?

@FaheemMitha Latex (on a good day) is about logical markup and separating structure from design. If you are putting in forced linebreaks you are having a bad day.

@DavidCarlisle I've doing proofreading of a book chapter that some idiots in India and Australia botched, including a totally pointless LaTeX to Word conversion So, yes, I'm having a bad day.

@DavidCarlisle: Can you explain the changes of @egreg please? tex.stackexchange.com/posts/108709/revisions

7:25 PM
@DavidCarlisle sudon't :)

@MarcoDaniel After you changed it you defined \_ but you need to define an active _

@DavidCarlisle But it worked? and I thought \mathcode\_="8000 makes it active

@MarcoDaniel consider the canonical case of ' if you use the catcode 12 ' in math it is mathcode "8000 so uses the definition of a catcode 13 ' (which is ^{\prime}) not the definition of \' which is one of those European accent thingies.

@DavidCarlisle Why the xkcd quoting?

@MarcoDaniel No it couldn't have worked:-)
@FaheemMitha Because it's the source of all wisdom.

7:29 PM
@FaheemMitha mind your post there may be anyone :)

@DavidCarlisle I guess I've been looking in all the wrong places.

@FaheemMitha see the discussion in the log just above about not being able to log out of here

@DavidCarlisle It worked ;-)
\documentclass{article}
\usepackage{fouriernc}

\begin{document}
$a_1$

$a_{\!1}$

\catcode\_=12
\mathcode\_="8000
\def\_#1{\sb{\!#1}}

$a_{1}$
$$1+1=1\label{eq_1}$$
Text \ref{eq_1} Text$_1$
\end{document}

@MarcoDaniel hang on...

@texenthusiast Hmm?
@DavidCarlisle Ah, I see.

7:31 PM
@FaheemMitha people nation :)

Where is Psmith when I need him?

@texenthusiast You lost me, sorry.

@MarcoDaniel you get no error but \def\_#1{\sb{\!#1}} isn't used as you don't use \_ anywhere.

!!/eightball - should I really get up at 5:30 tomorrow morning?

@topskip No.

7:32 PM
@DavidCarlisle Indeed. But why do I get a smaller distance?

@topskip Psmith has gone out for the day with Paulo.
@MarcoDaniel I assume you don't I'd better look:-)

@DavidCarlisle How should I decide on things without Psmith?

@DavidCarlisle Here a better demonstration:
\documentclass{article}
\begin{document}
\setbox0=\hbox{$a_1$}
\the\wd0

\setbox0=\hbox{$a_{\!1}$}
\the\wd0

\catcode\_=12
\mathcode\_="8000
\def\_#1{\sb{\!#1}}

\setbox0=\hbox{$a_1$}
\the\wd0
\end{document}

flio you do back to \tracingall....
@MarcoDaniel
{the character _}

_->\_

\_#1->\sb {\!#1}

@DavidCarlisle That means?

7:39 PM
@MarcoDaniel It means you got lucky.

@DavidCarlisle :-)

@MarcoDaniel LaTeX has a standing (normally unused) definition of active _ to be \_ so if it gets active and used for any reason it makes an underscore.
@MarcoDaniel so you made it catcode 12 and mathcode "8000 so what got used is the active definition of _ which you didn't set but that is defined via \def_{\_} so it expanded to \_ and then your definition of \_ took over

@DavidCarlisle and egreg's definition uses ~ which is normally active.
@DavidCarlisle I got lucky ;-)

@MarcoDaniel yes but only with the usual \lowercase triclk to get an active _
@MarcoDaniel your definition changed \_ so it couldn't be used to make _ in text anymore but egreg's didn't redefine ~ it just used ~ to get an active _ to redefine.

@DavidCarlisle I am trying to find a related question for the trick lowercase{\endgroup. I found a lot of answers which use this trick

7:49 PM
@MarcoDaniel ooh I'd forgotten: you didn't need to set mathcode of _ to "8000 it is already that. plain has ....
\mathcode\_="8000 % \_
{\catcode\_=\active \global\let_=\_} % _ in math is either subscript or \_
@MarcoDaniel It's the only thing lowercase is good for:-) There s a q on that I'll see...
@topskip read xkcd and gain inner wisdom

@DavidCarlisle You've forgotten more than I'll ever know.

@MarcoDaniel Don't know about that but I've certainly forgotten a lot:-) Apart from MWE here it really is a long while since I used TeX:-)
@MarcoDaniel @egreg's answer here:
10

Is there a way to use newcommand or some other nice technique to transform any occurence of "bla" in math mode into \text{bla} The reason I ask is because it is easy, and doesn't interrupt the flow of reading the (La)TeX code as much. I would like to keep Xe(La)TeX's nice quote behavior (i...

@DavidCarlisle Thanks

@MarcoDaniel Defining \_ has nothing to do with defining the active _.

@DavidCarlisle macros inside \lowercase won't be expanded.
@egreg David found out that I got lucky.

8:02 PM
@MarcoDaniel Yes, pure luck. :)
@MarcoDaniel But redefining \_ doesn't seem like a good idea.

@egreg Of course your trick is much better

@MarcoDaniel ?

@DavidCarlisle I am trying to understand the trick. \lowercase{\endgroup\def~} does -> \endgroup\def_ <- and it works locally because during the executing of \lowercase the assignment \lccode\~=\_ is active.

@MarcoDaniel \lowercase happens first (it is like tr in unix) it just passes over the token list changing tokens according to a lookup table (the lccodes)
so \lowercase{\endgroup\def~} produces \endgroup\def_ where _ has the catcode that ~ had which is 13

@DavidCarlisle But the assignment \lccode\~=\_ is done in group. How can the part \begingroup\lccode\~=\_\endgroup\def_work. (too many underscores :-) )

8:12 PM
@MarcoDaniel The \endgroup is not executed when \lowercase performs the change.

@egreg Ah. @DavidCarlisle and @egreg Thanks.

@MarcoDaniel \lowercase just scans over the token list replacing character tokens and leaving everything else untouched, then it puts the whole modified list back in the input stream and TeX starts processing again

@DavidCarlisle Now I understand the trick. The next level will be using the trick.

8:42 PM
Where is the best place to invoke \Init in the following scenario?
\documentclass[twocolumn]{article}
\usepackage[a4paper,margin=1cm]{geometry}
\usepackage{mathtools}
\newlength\EWD
\newlength\HWD
\newlength\HHWD

\def\Init{%
\settowidth{\EWD}{${}={}$}%
\setlength{\HWD}{0.5\dimexpr\linewidth-\EWD\relax}%
\setlength{\HHWD}{0.5\HWD}}

\def\TopLHS#1{\mathrlap{#1}\rule{\HWD}{0pt}}
\def\MiddleLHS#1{\rule{\HHWD}{0pt}\mathclap{#1}\rule{\HHWD}{0pt}}
\def\BottomLHS#1{\rule{\HWD}{0pt}\mathllap{#1}}

\begin{document}

\begin{enumerate}
\item\Init
\$\!
\begin{aligned}[t]`
The above code can be found in my answer here. I have to sleep. Bye!

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