[Rd] data() misbehaving inside a function
maechler at stat.math.ethz.ch
Fri Oct 17 09:28:59 MEST 2003
>>>>> "KH" == Kurt Hornik <Kurt.Hornik at wu-wien.ac.at>
>>>>> on Fri, 17 Oct 2003 09:04:40 +0200 writes:
>>>>> Peter Dalgaard writes:
>> David James <dj at research.bell-labs.com> writes:
>>> Calls of the form data(package = pkg) inside a function
>>> incorrectly fail ("pkg" is a local variable). For instance,
>>> foo <- function(pkg) data(package = pkg)
>>> Error in .find.package(package, lib.loc, verbose = verbose) :
>>> none of the packages were found
>> This is pretty much unavoidable if you want a function to accept
>> unquoted names. It's not in principle different from
>> women <- "airquality"
>> not being equivalent to data("airquality"). Some functions (library(),
>> require(), demo()) have a character.only argument to prevent it, and I
>> suppose we should consider putting it on help() and data() as well.
KH> Or get rid of non-standard evaluation and educate users to use quoted
KH> strings where strings should be used.
and infuriate those who know and used the S language for more
than 15 years, where help(help) has always worked?
Definitely not worth the pain (I *know* I'd hear ... comments from them!)!
I'd go for adding `character.only'.
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