Poor rendering in pkgdown of ?setorderv

[MichaelChirico]

Seen browsing:

Not sure if that's on our end or pkgdown:

data.table/man/setorder.Rd

Line 76 in 017fad8

is \code{TRUE} for \code{x[order(.)]} and \code{sort_by(x, .)} (\eqn{\R \ge 4.4.0}) to be consistent with \code{base::order}.

[aitap]

I'm not seeing the pkgdown website load Mathjax or KaTeX from anywhere. This is consistent with the documentation:

By default, pkgdown will render math using mathml. mathml is the official standard for rendering math on the web, and requires no additional javascript or css dependencies.

But how do they convert \eqn{} to MathML? There are as_html methods for the Rd tags, and then the math options are forwarded straight to pandoc, which indeed doesn't know about \R:

echo '$$ X[i,j,k] = \sum_r A_[i,r] B_[j,r] C_[k,r] $$' | pandoc --mathml
# <p><math display="block" xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>X</mi><mrow><mo stretchy="true" form="prefix">[</mo><mi>i</mi><mo>,</mo><mi>j</mi><mo>,</mo><mi>k</mi><mo stretchy="true" form="postfix">]</mo></mrow><mo>=</mo><munder><mo>∑</mo><mi>r</mi></munder><msub><mi>A</mi><mrow><mo stretchy="true" form="prefix">[</mo><mi>i</mi><mo>,</mo><mi>r</mi><mo stretchy="true" form="postfix">]</mo></mrow></msub><msub><mi>B</mi><mrow><mo stretchy="true" form="prefix">[</mo><mi>j</mi><mo>,</mo><mi>r</mi><mo stretchy="true" form="postfix">]</mo></mrow></msub><msub><mi>C</mi><mrow><mo stretchy="true" form="prefix">[</mo><mi>k</mi><mo>,</mo><mi>r</mi><mo stretchy="true" form="postfix">]</mo></mrow></msub></mrow><annotation encoding="application/x-tex"> X[i,j,k] = \sum_r A_[i,r] B_[j,r] C_[k,r] </annotation></semantics></math></p>
echo '$$ \R $$' | pandoc --mathml
# [WARNING] Could not convert TeX math  \R , rendering as TeX:
#    \R 
#      ^
#   unexpected control sequence \R
#   expecting "%", "\\label", "\\tag", "\\nonumber" or whitespace
# <p><span class="math display">$$ \R $$</span></p>

Could also be some other problem, because on the pkgdown page, we don't even get a <span class="math display">. Also, my copy of Pandoc doesn't seem to recognise math in \(...\) without additional format extensions.

Maybe setting a Javascript math renderer will help.

See also: r-lib/pkgdown#2704

[m-muecke]

@MichaelChirico the math rendering default has been changed in recent pkgdown versions. One has to opt-in for better latex support.
I usually go with mathjax, should also be the old default:

url: https://rdatatable.gitlab.io/data.table

template:
  bootstrap: 5
  light-switch: true
  math-rendering: mathjax

[ben-schwen]

Adding math-rendering: mathjax resolves the problem of rendering \ge but still does not render \R

[MichaelChirico]

do we really need \eqn{} to discuss R version requirements?

[MichaelChirico]

I don't see any other package doing so really:

https://github.com/search?q=org%3Acran%20path%3A%2F%5C.Rd%24%2F%20%2F%5B%5C%5C%5DR%5Cs*(%5B%5C%5C%5D%5Cw%2B%7C%5B%3C%3E%3D%5D%2B)%5Cs*%5B0-9%5D%2F&type=code

https://github.com/search?q=org%3Acran+path%3A%2F%5C.Rd%24%2F+%2F%5B%5C%5C%5DR%5Cs*%28%5B%5C%5C%5D%5Cw%2B%29%5Cs*%5B0-9%5D%2F&type=code

cc @rikivillalba (3aee430), I assume it was added to look a little nicer but won't be missed.