about slow syntax highlighting #2877
Description
Description
vimtex's syntax highlighting is a bit slow at times. It's not terrible but if I open a large tex file and scroll up and down with my touchpad it is noticably not smooth. I've tried to look at the output of :syntime report and see if there's anything that can be improved. Here's the output
TOTAL COUNT MATCH SLOWEST AVERAGE NAME PATTERN
0.222296 81139 74810 0.000459 0.000003 texMathDelim [()[\]]\|\\[{}]
0.146481 21673 49 0.000507 0.000007 texLigature \v%(``|''|,,)
0.105568 25166 79 0.000556 0.000004 texSpecialChar \%(\\\@<!\)\@<=\~
0.090826 21627 0 0.000207 0.000004 texMathZoneLI \%(\\\@<!\)\@<=\\(
0.084873 70591 61790 0.000521 0.000001 texMathSuperSub [_^]
0.060983 74427 498 0.000408 0.000001 texMathZoneTI \\\\\|\\\$
0.060684 38720 30212 0.000448 0.000002 texMathOper [-+=/<>|]
0.039987 51544 45011 0.000128 0.000001 texMathCmd \\\a\+
0.022891 26430 6532 0.000241 0.000001 texComment %.*$
0.022842 25192 16306 0.000065 0.000001 texMathDelimMod \\\(left\|right\)\>
0.021043 23855 4193 0.000384 0.000001 texMathGroup \\\\\|\\}
0.020043 32248 17368 0.000079 0.000001 texCmd \\[a-zA-Z@]\+
0.020011 5365 209 0.000412 0.000004 texCommentAcronym \v<(\u|\d){3,}s?>
0.019337 5194 3 0.000303 0.000004 texCommentURL \w\+:\/\/[^[:space:]]\+
0.018543 21627 0 0.000066 0.000001 texCmdConditionalINC \\\w*@ifnextchar\>
0.016475 21627 0 0.000101 0.000001 texCmdLigature \v\\%([ijolL]|ae|oe|ss|AA|AE|OE)\ze[^a-zA-Z@]
0.016086 21627 0 0.000052 0.000001 texSynIgnoreZone ^\c\s*% VimTeX: SynIgnore\%( on\| enable\)\?\s*$
0.014915 16338 3614 0.000067 0.000001 texMathArg \\\\\|\\}
0.014743 21627 0 0.000047 0.000001 texCmdSpaceCode \v\\%(math|cat|del|lc|sf|uc)code`
0.014660 21627 38 0.000082 0.000001 texMathZoneEnv \\begin{\z(cd\*\?\)}
0.014640 14477 12771 0.000071 0.000001 texMathTextAfter \w\+
0.014227 22104 563 0.000064 0.000001 texCmdCRef \v\\%(%(label)?c%(page)?|C)ref>
0.014106 25136 0 0.000119 0.000001 texCmdRef \\\(page\|eq\)ref\>
0.014085 23605 6905 0.000066 0.000001 texCmdEnv \v\\%(begin|end)>
0.013869 21627 0 0.000103 0.000001 texCmdLigature \v\\%([ijolL]|ae|oe|ss|AA|AE|OE)$
0.013798 25136 0 0.000148 0.000001 texComment ^\s*\\iffalse\>
0.013527 25136 0 0.000438 0.000001 texCmdRef \\v\?ref\>
0.013382 25136 0 0.000124 0.000001 texComment ^\s*%\s*!.*
0.012572 21627 0 0.000061 0.000001 texCmdPart \\\(front\|main\|back\)matter\>
0.012235 25172 48 0.000079 0.000000 texSpecialChar \\[,;:!>]
0.011866 21654 103 0.000117 0.000001 texCmdConditional \\\(if[a-zA-Z@]\+\|fi\|else\)\>
0.011844 21627 0 0.000047 0.000001 texConditionalTrueZone ^\s*\\iftrue\>
First of all, I think the very slow \v%(``|''|,,) can be replaced by the equivalent \([`',]\)\1, which was slightly faster for me, averaging 4us instead of 7us.
I was very confused by \%(\\\@<!\)\@<=\~. Am I correct in understanding that
- it is equivalent to
\\\@<!\~ - the point of making it more complicated is that it will match faster (with a naive regex engine): After finding a
~, it will only try to check if there's a backslash before the~once, instead of trying to match every substring ending before~against the regex\\?
If so then the same behavior could be achieved with\\\@1<!\~which looks simpler. Unfortunately it doesn't seem to give a speedup.
Another point is that this regex will parse something like a\\~b wrongly. This is more relevant for parsing something like \\\(a^2\) -- this is valid latex but vimtex's highlighting currently doesn't recognize the math mode (OTOH I don't know why anyone would ever write that). The regex \%(\\\@!\%(\\\\\)*)\@<=\\( would fix this, checking if there's an even number of backslashes before the \(. Same goes for detecting ~. The performance of this seems to be slightly worse than \%(\\\@!)\@<=\\( though. I got 11us vs 9us.
Do you use a latexmkrc file?
No
VimtexInfo
System info:
OS: Ubuntu 23.10
Vim version: NVIM v0.10.0-dev-2175+g85a041716
Has clientserver: true
Servername: /run/user/1000/nvim.242708.0
VimTeX project: m
base: m.tex
root: /home/ca/vim
tex: /home/ca/vim/m.tex
main parser: current file verified
document class: article
packages: accents aliascnt aliasctr amsbsy amsfonts amsgen amsmath amsopn amssymb amstext amsthm atbegshi atbegshi-ltx atveryend atveryend-ltx autonum auxhook bigintcalc bitset calc cleveref color csquotes enumitem epstopdf-base etex etextools etoolbox geometry gettitlestring graphics graphicx hycolor hypcap hyperref iftex ifthen ifvtex infwarerr inputenc intcalc keyval kvdefinekeys kvoptions kvsetkeys letltxmacro ltxcmds mathrsfs mathtools mhsetup mleftright nameref parseargs pdfescape pdftexcmds pgf pgfcomp-version-0-65 pgfcomp-version-1-18 pgfcore pgffor pgfkeys pgfmath pgfrcs pgfsys refcount rerunfilecheck rotating textpos tgpagella thm-amsthm thm-autoref thm-kv thm-listof thm-patch thm-restate thmtools tikz tikz-cd todonotes trig uniquecounter url xcolor xkeyval
source files:
m.tex
../texmf/tex/latex/preamble.tex
compiler: latexmk
engine: -pdf
options:
-verbose
-file-line-error
-synctex=1
-interaction=nonstopmode
callback: 1
continuous: 1
executable: latexmk
viewer: Zathura
xwin id: 0
qf method: LaTeX logfile