Problems about the math mode

I have several problems about equations when I use TeXmacs to do my physics homework.

  1. Bug report: bracket can’t fully encase the content:

  2. Long equation and automatic line feed: From time to time I need to write extra long equations which need several lines, but the automatic equation line feed looks awful. Here’s my example:

    Now I use <next-line> with <htab|5mm> to make it nicer: But it’s not satisfying neither. Is there any elegant way for long formulae?

  3. Extensive line for the range of integration after the antiderivative: I’m not sure if I explain it correctly, but you can see this:

    In the screenshot above, I first input | Tab Tab which means “extensible middle bar”, then the length of the bar is fine. But as long as I type the range (subscript and superscript), the bar becomes short as shown in the picture.

  4. Improve the “Negation”: SharedScreenshot13 Is there any possibility that TeXmacs has the same function as: https://jansoehlke.com/2010/06/strikethrough-in-latex/

About point 3: I think a reasonable way to achieve the result is to use a bracketing environment. You put your formula into a |…| environment and then you go back and delete the first vertical bar. This will maintain the environment and will give the right height to the right bar.

About point 1: I think this is not a bug, but a feature: there is no typographical reason the brackets should encompass all the vertical size of the content. Actually I find TeXmacs’ solution quite pleasant. If you want you can manually increase the size of the brackets.

About point 2: my solution is to use a table and manually dispatch content in different lines, eventually adding some initial spacing. Mathematical line breaking cannot be implemented automatically (or at least very difficult and unreliable)

Yeah, mostly this bracket won’t cause any problem. I didn’t realize it until I compared this equation with the identical one on my teacher’s lecture note which is type set by LaTeX and find they have tiny difference. Don’t want to stir up argument, but I thought TeXmacs and LaTeX should render out same equations.

I do not think so, and I think neither the main developer, Joris. There is nothing sacred in the way LaTeX do typesetting, and personally I do not see anything wrong in the example you showed, actually I never liked overly large brackets. Typography matters about readibility and visually pleasant arrangements. If you had to compare to LaTeX to see the difference then it means in the first place that there were nothing wrong with the typesetting. I find pleasant that the presence of a small 2 does not compromise the general layout of the brackets, would be non-sense otherwise. If you want to complain about something I think it would be the fact that there is too much space in the indexes of \sigma_1 and \sigma_2, I would have put the numers nearer to the symbols. And also too much space between the round brackets and the fraction.

And in general, TeXmacs is not meant as a pixel-by-pixel/feature-by-feature substitute of TeX/LaTeX. It would not make sense.

As for point 4: you can have something like

<\equation*>
  <big|int>\<mathd\>\<varphi\><frac|<text|<deleted|<math|e<rsup|i q r
  cos\<theta\>>>>>|r>
</equation*>

I never say TeXmacs should be a pixel-by-pixel/feature-by-feature substitute of TeX/LaTeX. I agree what you said “Typography matters about readibility and visually pleasant arrangements.” and I plus one more: convenience. So what I ask for today is readability, method and convenience of method. I always use LaTeX as an example because I want to address my problem efficiently and precisely. There’s no way to expose your intention better than giving examples. Unfortunately, my examples just come from LaTeX, since there’s not many popular typesetting tools and they do have many similarities to compare. I had never ever imply that TeXmacs is a follower of TeX/LaTeX to undermine the value of this software. So there’s no need to be sensitive and allergic to those words about LaTeX. Maybe my question 1 is controversial, I thought it’s a bug, you say no. Then that’s it! I think you did more: you want to show how wrong I was to have this question even asked, which I think isn’t good. Besides, I said “I thought TeXmacs and LaTeX should render out same equations.” means “I used to think, but now I don’t.
Anyway, besides those words defending myself, I want to say thank you for your help. Your answers are very helpful. Your codes about the style of section gives me a very good example to learn TeXmacs further.

Sorry for having been harsh, i interpreted “Don’t want to stir up argument, but I thought TeXmacs and LaTeX should render out same equations.” as a way to enforce your previous statement, not as a way to “milden” it. So I tried to make my point clearer, maybe too directly.