7.31.1 Top new questions this week

7.31.1.1 *Why* does TeX not allow numbers in command names?

https://tex.stackexchange.com/landing/r/digest?cta=question&id=598250

I am not asking how the syntax of TeX works. I know perfectly well that only letters are allowed in command names, except for single-character names and constructions using \csname. Ia^\200\231m just asking: ... 
[macros] [tex-history]
 

asked by Gaussler https://tex.stackexchange.com/landing/r/digest?cta=user&id=19809 44 votes

answered by ShreevatsaR https://tex.stackexchange.com/landing/r/digest?cta=user&id=48 43 votes

7.31.1.2 Fading arrows in TikZ

https://tex.stackexchange.com/landing/r/digest?cta=question&id=597927

I'm trying to add fadings on arrows in a TikZ picture, but when I add a fading on a vertical arrow, the arrow tip partly disappears. 
\documentclass{article} 
\usepackage{tikz} 
\usetikzlibrary{fadings} 
... 
[tikz-pgf]
 

asked by Vincent https://tex.stackexchange.com/landing/r/digest?cta=user&id=201628 12 votes

answered by hpekristiansen https://tex.stackexchange.com/landing/r/digest?cta=user&id=8650 16 votes

7.31.1.3 siunitx 3 "quotient-mode" has been removed in this release

https://tex.stackexchange.com/landing/r/digest?cta=question&id=598236

With the upgrade to version 3.0.0 of siunitx it is no longer possible to use fractions in units. 
Consider this minimal example: 
\documentclass{article} 
\usepackage{siunitx} 
\sisetup{ 
quotient-mode ... 
[siunitx]
 

asked by Claudio https://tex.stackexchange.com/landing/r/digest?cta=user&id=16713 10 votes

answered by Joseph Wright https://tex.stackexchange.com/landing/r/digest?cta=user&id=73 8 votes

7.31.1.4 What is kcatcode in pTeX and upTeX?

https://tex.stackexchange.com/landing/r/digest?cta=question&id=598337

The Japanese TeX engines pTeX and upTeX treat separately Latin and Japanese characters, in a way I don't fully understand.  They introduce a notion of kcatcode of a Japanese character, which takes ... 
[tex-core] [japanese] [ptex]
 

asked by Bruno Le Floch https://tex.stackexchange.com/landing/r/digest?cta=user&id=2707 9 votes

answered by Hironobu YAMASHITA https://tex.stackexchange.com/landing/r/digest?cta=user&id=89193 9 votes

7.31.1.5 How can typeset \qty 4\pi e-7  \henry\per\meter  in siunitx version v3.0.2

https://tex.stackexchange.com/landing/r/digest?cta=question&id=597998

In previous siunitx I was able to typeset permeability constant: 
\SI{4\pi e-7}{\henry\per\meter} 
I just expect that it can be simple rewritten to 
\gty{4\pi e-7}{\henry\per\meter} 
but Siunitx ... 
[siunitx]
 

asked by JardaFait https://tex.stackexchange.com/landing/r/digest?cta=user&id=17229 9 votes

answered by Joseph Wright https://tex.stackexchange.com/landing/r/digest?cta=user&id=73 13 votes

7.31.1.6 Why can I not define commands beginning with "\end" with \newcommand?

https://tex.stackexchange.com/landing/r/digest?cta=question&id=598487

Note: I have seen a seemingly duplicate question at Why I can not define commands starting with \end? that offers a workaround but does not really answer the "Why" part of the question. This ... 
[macros]
 

asked by Lone Learner https://tex.stackexchange.com/landing/r/digest?cta=user&id=18587 6 votes

answered by Steven B. Segletes https://tex.stackexchange.com/landing/r/digest?cta=user&id=25858 8 votes

7.31.1.7 Tikz: draw two paths between a pair of objects

https://tex.stackexchange.com/landing/r/digest?cta=question&id=598747

I want these arrows to be parallel. 
Why isn't yshift working the same way on the start and end of the path? 
Is there a better way to choose locations on the boxes? Is there an anchor for halfway up ... 
[tikz-pgf] [flow-charts]
 

asked by Lucas https://tex.stackexchange.com/landing/r/digest?cta=user&id=222293 6 votes

answered by Sigur https://tex.stackexchange.com/landing/r/digest?cta=user&id=14757 7 votes