Display math in R documentation

Helper function to insert tex math expressions into R documentation (.rd) files. Uses Katex rendering for documentation in html format, and the appropriate latex macros for documentation rendered in pdf or plain-text.

Usage

math_to_rd(tex, ascii = tex, displayMode = TRUE, ..., include_css = TRUE)

Arguments

tex

input string with tex math expression.

ascii

alternate text-only representation of the input math to show in documentation rendered to plain text format.

displayMode

render math in centered 2D layout, similar to $$ in tex. Set to FALSE to render (non-centered) inline layout for use in text. For pdf output, this corresponds to the \deqn{} and \eqn{} macros, see WRE 2.6: Mathematics

...

additional html rendering options passed to katex.render

include_css

adds the katex css file to the output. This is only required once per html webpage. Set to FALSE if you include css files into the your html head some other way.

Value

a string with an rd fragment to be included in R documentation

Details

Use math_to_rd() inside \Sexpr to embed math in your R package documentation pages. For example the code below can be inserted in your rd (or roxygen) source code:

\Sexpr[results=rd, stage=build]{
  katex::math_to_rd(katex::example_math())
}

Which results in the following output:

$$f(x)= {\frac{1}{\sigma\sqrt{2\pi}}}e^{- {\frac {1}{2}} (\frac {x-\mu}{\sigma})^2}$$

Optionally you can specify an alternate ascii representation that will be shown in the plain-text format rendering of the documentation:

\Sexpr[results=rd, stage=build]{
  katex::math_to_rd('E=MC^2', 'E=mc²')
}

$$E=MC^2$$

If no ascii representation is given, the input tex in displayed verbatim into the plain-text documentation.

Note for Windows

On Windows, R versions before 4.1.2 had a bug which could lead to incorrect HTML encoding for \Sexpr{} output. As a workaround, we automatically escape non-ascii html characters on these versions of R. Linux and MacOS are unaffected.

See also

Other katex: katex, pandoc