Supply macro definitions in print.dev_help

[hadley]

print.dev_topic() — the documentation suggests that ... in Rd2txt() and Rd2html() is passed on to parse_Rd(). I don't remember exactly what you need to supply in the macros argument, but I'm pretty sure I got it working in pkgdown.

Would also need to work with the IDE team to get the necessary information passed along to the previewRd() API call.

[dmurdoch]

This has come up in this discussion: https://stat.ethz.ch/pipermail/r-package-devel/2020q2/005420.html. The mathjaxr package supplies macros to allow MathJax to be used in Rd help files; packages need to list it in the RdMacros field in DESCRIPTION. pkgload::load_rd_macros() should be looking there.

[lionel-]

IIUC, this is a duplicate of #115 which was fixed in #116. Am I missing something @hadley?

[hadley]

@lionel- I think @dmurdoch is saying that the current support is incomplete — as well as loading the macros defined in the current package, we also need to load the packages provided by the packages listed in the RdMacros field.

[lionel-]

ok I think I understand now, we already have support for foreign and local RdMacros outside RStudio that Gabor implemented in #116. I have added unit tests in #205 (see also e3c282a which fixes a bug in RStudio introduced in this PR).

What was missing is support inside RStudio because we call into the IDE API in that case. @dmurdoch opened an issue about foreign macros in rstudio/rstudio#6871 which has been fixed by Kevin since. However, it seems that local macros are still not loaded. I have opened rstudio/rstudio#11336 to get this fixed.

I think we can now close this but please let me know if I'm still missing something.

[lionel-]

Kevin found a way for us to display our own generated html files in the help pane of RStudio.