syntax-definitions: KDE language syntax definition files (XML), or an array of values?

[baptiste]

Description

I'm wondering how one is supposed to use the syntax-definitions field; according to the docs:

syntax-definitions 	
KDE language syntax definition files (XML)

but when I have this in my yaml,

format:
  html:
    theme: cosmo
    highlight-style: arrow
    syntax-definitions: julia.xml

I get an immediate type-check error from quarto:

Field "syntax-definitions" has value julia.xml, which must instead be an array of values, where each element must be a string
68:     highlight-style: arrow
69:     syntax-definitions: julia.xml
                           ~~~~~~~~~~
✖ The value julia.xml is of type string.

Is there an example using this syntax-definitions option? I'm trying to see if I can improve the look of syntax highlighting in black and white, at the moment the words set in bold don't seem to match the language very well.

[baptiste]

Here's a julia.xml definition file that I got from the KDE website

[mcanouil]

This is an option passed through directly to Pandoc, see https://pandoc.org/MANUAL.html#syntax-highlighting.

[baptiste]

I wonder how one can pass it through quarto. I've tried syntax-definitions: ["julia.xml"], which passes the parsing check, but it seems to hang forever when knitting.

[mcanouil]

Did you try your file directly through Pandoc? quarto pandoc file.qmd --from markdown --to whatever -o output.extension

[baptiste]

It's also not working, so I guess there's more than one problem:

quarto pandoc test-hi.qmd --from markdown --to html --syntax-definition julia.xml -o test-hi.html

with this file

---
title: "Untitled"
---


```julia
using Plots

plot(sin, 
     x->sin(2x), 
     0, 
     2π, 
     leg=false, 
     fill=(0,:lavender))
```

gives me a warning:

Error compiling regex \.\.\.?|[:$]=?|\.?(?:>>>=|<-->|//=|<<=|>>=|-->|<--|===|!==|>>>|[-+*/\\^÷%|&⊻]=|=>|&&|\|\|?|>=|<=|==|!=|<\||\|>|\+\+|//|<<|>>|<:|>:|[\Q=≔⩴≕~←→↔↚↛↞↠↢↣↦↤↮⇎⇍⇏⇐⇒⇔⇴⇶⇷⇸⇹⇺⇻⇼⇽⇾⇿⟵⟶⟷⟹⟺⟻⟼⟽⟾⟿⤀⤁⤂⤃⤄⤅⤆⤇⤌⤍⤎⤏⤐⤑⤔⤕⤖⤗⤘⤝⤞⤟⤠⥄⥅⥆⥇⥈⥊⥋⥎⥐⥒⥓⥖⥗⥚⥛⥞⥟⥢⥤⥦⥧⥨⥩⥪⥫⥬⥭⥰⧴⬱⬰⬲⬳⬴⬵⬶⬷⬸⬹⬺⬻⬼⬽⬾⬿⭀⭁⭂⭃⭄⭇⭈⭉⭊⭋⭌￩￫⇜⇝↜↝↩↪↫↬↼↽⇀⇁⇄⇆⇇⇉⇋⇌⇚⇛⇠⇢↷↶↺↻><≥≤≡≠≢∈∉∋∌⊆⊈⊂⊄⊊∝∊∍∥∦∷∺∻∽∾≁≃≂≄≅≆≇≈≉≊≋≌≍≎≐≑≒≓≖≗≘≙≚≛≜≝≞≟≣≦≧≨≩≪≫≬≭≮≯≰≱≲≳≴≵≶≷≸≹≺≻≼≽≾≿⊀⊁⊃⊅⊇⊉⊋⊏⊐⊑⊒⊜⊩⊬⊮⊰⊱⊲⊳⊴⊵⊶⊷⋍⋐⋑⋕⋖⋗⋘⋙⋚⋛⋜⋝⋞⋟⋠⋡⋢⋣⋤⋥⋦⋧⋨⋩⋪⋫⋬⋭⋲⋳⋴⋵⋶⋷⋸⋹⋺⋻⋼⋽⋾⋿⟈⟉⟒⦷⧀⧁⧡⧣⧤⧥⩦⩧⩪⩫⩬⩭⩮⩯⩰⩱⩲⩳⩵⩶⩷⩸⩹⩺⩻⩼⩽⩾⩿⪀⪁⪂⪃⪄⪅⪆⪇⪈⪉⪊⪋⪌⪍⪎⪏⪐⪑⪒⪓⪔⪕⪖⪗⪘⪙⪚⪛⪜⪝⪞⪟⪠⪡⪢⪣⪤⪥⪦⪧⪨⪩⪪⪫⪬⪭⪮⪯⪰⪱⪲⪳⪴⪵⪶⪷⪸⪹⪺⪻⪼⪽⪾⪿⫀⫁⫂⫃⫄⫅⫆⫇⫈⫉⫊⫋⫌⫍⫎⫏⫐⫑⫒⫓⫔⫕⫖⫗⫘⫙⫷⫸⫹⫺⊢⊣⟂⫪⫫…⁝⋮⋱⋰⋯+-−¦|⊕⊖⊞⊟∪∨⊔±∓∔∸≏⊎⊻⊽⋎⋓⧺⧻⨈⨢⨣⨤⨥⨦⨧⨨⨩⨪⨫⨬⨭⨮⨹⨺⩁⩂⩅⩊⩌⩏⩐⩒⩔⩖⩗⩛⩝⩡⩢⩣*/⌿÷%&··⋅∘×\∩∧⊗⊘⊙⊚⊛⊠⊡⊓∗∙∤⅋≀⊼⋄⋆⋇⋉⋊⋋⋌⋏⋒⟑⦸⦼⦾⦿⧶⧷⨇⨰⨱⨲⨳⨴⨵⨶⨷⨸⨻⨼⨽⩀⩃⩄⩋⩍⩎⩑⩓⩕⩘⩚⩜⩞⩟⩠⫛⊍▷⨝⟕⟖⟗⨟^↑↓⇵⟰⟱⤈⤉⤊⤋⤒⤓⥉⥌⥍⥏⥑⥔⥕⥘⥙⥜⥝⥠⥡⥣⥥⥮⥯￪￬\E]): Failed reading: parse error at byte position 18

which, to be fair, looks like a rather unorthodox regex ¯_(ツ)_/¯

[mcanouil]

So it would seem to be a Pandoc issue rather than Quarto.
Maybe worth checking Pandoc repository for related issues, and possibly report this one (if you are sure your file is correct).

[cderv]

I wonder how one can pass it through quarto. I've tried syntax-definitions: ["julia.xml"], which passes the parsing check, but it seems to hang forever when knitting.

@baptiste I can confirm this the way to pass it . Autocompletion should help you here. It leads me to this below, which is equivalent to the above:

format: 
  html:
    syntax-definitions: 
      - julia.xml

Though I get the same error as you regarding the regex. It seems like the regex is in Pandoc's bundled file (https://github.com/jgm/skylighting/blob/master/skylighting-core/xml/julia.xml) but when using the CLI flag, it creates the issue.

It is worth reporting upstream to PANDOC IMO, as @mcanouil already advice.

[baptiste]

I was a bit surprised by the quarto side of things as well, because the documentation is quite terse and without an example one might assume that passing a xml filename should work.

I'll try to ask on the Pandoc list; it's puzzling that it uses it fine internally but not when passed from the command line.