[R-pkg-devel] help fixing CRAN package sos-now fails on GitHub

[Duncan Murdoch]

On 23/05/2023 6:53 a.m., Martin Maechler wrote:
>>>>>> Duncan Murdoch
>>>>>>      on Mon, 22 May 2023 15:38:10 -0400 writes:
> 
>      > On 22/05/2023 3:07 p.m., Ivan Krylov wrote:
>      >> I fed your vignette to R CMD Sweave, and here's the
>      >> relevant fragment from the resulting *.tex file:
>      >>
>      >>> This returned a {\tt "findFn"} object identifying 405
>      >>> help pages.  When this was run while preparing this
>      >>> manuscript, the sixth row was {\tt pspline_checker} in
>      >>> the \pkg{JOPS} package, which has a {\tt Score} of
>      >>> 47. (On another day, the results could be different,
>      >>> because CRAN changes over time.)  This was the sixth row
>      >>> in this table, because it is in the \pkg{JOPS} package,
>      >>> which had a total of 54 help pages matching the search
>      >>> term, but this was the only one whose name matched the
>      >>> {\tt pattern} passed to {\tt grepFn}.
>      >>
>      >> This corresponds to the following part of the vignette:
>      >>
>      >>> This returned a {\tt "findFn"} object identifying
>      >>> \Sexpr{nrow(g)} help pages.  When this was run while
>      >>> preparing this manuscript, the sixth row was {\tt
>      >>> \Sexpr{gFunc6}} in the \pkg{\Sexpr{gPac6}} package,
>      >>> which has a {\tt Score} of \Sexpr{gScore6}.
>      >>
>      >> So, you need to escape the underscores in
>      >> gFunc6. Probably not gPac6 because underscores are not
>      >> allowed in package names.
>      >>
> 
>      > Nice find.  Just in case Spencer has trouble with escaping
>      > the escapes, I think he should change
> 
>      >    "{\tt \Sexpr{gFunc6}}"
> 
>      > to
> 
>      >    "{\tt \Sexpr{sub("_", "\\\\_", gFunc6)}}
> 
>      > Even better would be to write a little function
>      > "sanitizeForLatex" that did this and any other necessary
>      > changes, and call that.
> 
> Yes, indeed (2 x).
> 
> If I grep the base R package sources, I find three occurrences
> of something like the above:
> 
> grep --color -nH --null -e 'sub *(.*\\\\_' */R/*.R
> 
>   tools/R/Rd2latex.R:295:        x <- fsub("\\_", "_", x)
>   tools/R/Rd2latex.R:303:        x <- fsub("\\_", ".Rul.", x)
>   tools/R/Rd.R:681:    txt <- gsub("\\_", "_", txt, fixed=TRUE)
> 
> all of which do the transformation in the other direction
> (because *.Rd in those cases already *is* LaTeX-alike, and needs
>   to convert for non-LaTeX use).
> 
> Note that the last one gives a hint to be more general --- gsub()
> also working a.g. for 'parse_me_not' ---
> *and* possibly faster (fixed=TRUE)  leading to
> 
>       "{\tt \Sexpr{gsub("_", "\\\\_", gFunc6, fixed=TRUE)}}
> 
> Martin

Yes, a good idea to use gsub and fixed = TRUE.

There are some changes in the other direction as well in that file (Rd 
format is very complicated).  I think the characters it handles are \, 
&, $, %, _, #, {, }, ^, ~, occurring near line 145.  Only _ is allowed 
in a "syntactic" name, but others might turn up when trying to display 
other code.

Duncan