Rd parser throws error for user macros invoked with empty argument
While on the topic of Rd macro arguments, it seems that if a multiline argument is supplied, the lines after the first are silently ignored:
f <- tempfile()
mac6 <- "\\newcommand{\\mac6}{mac6: #1}"
cat(mac6, "\\mac6{2*3
2+2
sin(pi)
}\n", file = f)
rd <- tools::parse_Rd(f)
rd
mac6: 2*3
---
Georgi Boshnakov
-----Original Message-----
From: Tomas Kalibera [mailto:tomas.kalibera at gmail.com]
Sent: 25 May 2018 10:05
To: Georgi Boshnakov; r-devel at r-project.org
Subject: Re: [Rd] Rd parser throws error for user macros invoked with empty argument
Thanks for the report and the examples - and they do not have to be that
verbose, it is enough to just define and use a command, e.g.
cat("\\newcommand{\\mac1}{MAC1:#1}\\mac1{}", file=f)
rd <- tools::parse_Rd(f)
Whenever you get an error message like "Value of SET_STRING_ELT() must
be a 'CHARSXP' not a 'NULL'", there is a bug (at least the error message
should be relevant/informative).
I am testing a patch that will allow empty arguments to macros (they
will expand to an empty string, like in LaTeX).
Best
Tomas
On 05/14/2018 11:23 PM, Georgi Boshnakov wrote:
Bug or feature?
I get the following error from parse_Rd() when a user Rd macro (including system ones) is invoked with empty argument {},
eg \mymacro{}:
Error in tools::parse_Rd(fn) :
Value of SET_STRING_ELT() must be a 'CHARSXP' not a 'NULL'
A full example is further below with the system macro \CRANpkg{}. In this example it doesn't make sense to use empty argument but the error is not specific to this particular macro.
------
Georgi Boshnakov
Create an Rd file containing system macro \CRANpkg{bibtex}, parse_Rd() is ok:
=================
fn <- tempfile()
writeLines("\\name{dummyfun}
\\alias{dummyfun}
\\title{Dummy title}
\\description{Dummy description}
\\usage{
dummyfun(x, ...)
}
\\arguments{
\\item{x}{a value.}
\\item{\\dots}{further arguments.}
}
\\details{
\\CRANpkg{bibtex}
}
", fn)
tools::parse_Rd(fn)
...
\details{
\href{{https://CRAN.R-project.org/package=bibtex}{\pkg{bibtex}}}
}
================
With empty argument - \CRANpkg{} - Rd parser throws error. Of course it is silly in this example but I have used it with other user defined macros where it may make sense to have empty argument.
================
writeLines("\\name{dummyfun}
\\alias{dummyfun}
\\title{Dummy title}
\\description{Dummy description}
\\usage{
dummyfun(x, ...)
}
\\arguments{
\\item{x}{a value.}
\\item{\\dots}{further arguments.}
}
\\details{
\\CRANpkg{}
}
", fn)
tools::parse_Rd(fn)
Error in tools::parse_Rd(fn) : Value of SET_STRING_ELT() must be a 'CHARSXP' not a 'NULL' [[alternative HTML version deleted]]
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