[R] Seemingly bizarre behavior in R CMD check

Bartz, Kevin Kevin.Bartz at FMR.COM
Fri Jul 27 16:14:14 CEST 2001

Maybe someone can help shed some light on an odd and repeatedly irritating
error I noticed when running the check Perl script on my R 1.3 project. In
following it line by line, I traced my problem down to the
code/documentation matching within check, the most recent version of which
seems to verify proper .Rd formatting by means of R's codoc and undoc
functions. Under R --vanilla, those two then unpack and repack my project,
with each assembling a kind of test tempfile to ensure various structural
requirements within my project. At first, I got bogged down in a mysterious
"parse" problem, R's not-too-revealing result of a simple eval, but after
discovering the keep.tempfiles flag I was able to trace the obvious errors
without running codoc line by line interactively. Apparently, R keeps very
stringent requirements on its documentation's usage field. If it's anything
other than myFunc(arg1, arg2...), codoc won't parse it correctly in its
tempfiles. And the particular S code I was translating used chiefly example
calls in its documentation's usage fields. Is this formatting an intended
necessity? I know it ensures consistency but it's too often the source of
cryptic errors. 

Anyway, fixing these usage fields worked for the time being but without fail
another similar problem soon emerged, this time with the check for
undocumented objects. This leg of the script uses undoc, and after
examination I found that undoc's concatenation of the R code in the
project/R directory fails to insert a newline at the end of each .R file's
contribution to the appended tempfile. Now I'm a clean kind of guy and I
like to keep my code immaculate, so it was more than disturbing when my R
functions, each stored in a single .R file, bombed out because each did not
have a newline proceeding its closing bracket. Without that, undoc's file
appending sticks the next function right up against the last's final
bracket, triggering an obvious syntax error, albeit one hidden underneath
tempfiles and a parse/eval combo. Now I can understand somewhat the benefits
of establishing consistency in the usage fields, but for the life of me I
can't figure out the reasoning behind this seemingly superfluous stringency.
Is this R's intended behavior, and if so, forgive me for asking, but why?

Thanks in advance for any light you can cast on the issue.

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