Hi
It seems that names of the form "..#" and "..." are not
fixed by
make.names(), even though they are reserved words. The documentation reads:
> [...] Names such as ".2way" are not valid, and neither are the
reserved words.
> Reserved words in R: [...] ... and ..1, ..2 etc, which are used to
refer to arguments passed down from a calling function, see ?... .
I have pasted a reproducible example below.
I'd like to suggest to convert these to "...#" and
"....", respectively.
Happy to contribute PR.
Best regards
Kirill
make.names(c("..1", "..13", "..."))
#> [1] "..1"? "..13" "..."
`..1` <- 1
`..13` <- 13
`...` <- "dots"
mget(c("..1", "..13", "..."))
#> $..1
#> [1] 1
#>
#> $..13
#> [1] 13
#>
#> $...
#> [1] "dots"
`..1`
#> Error in eval(expr, envir, enclos): the ... list does not contain any
elements
`..13`
#> Error in eval(expr, envir, enclos): the ... list does not contain 13
elements
`...`
#> Error in eval(expr, envir, enclos): '...' used in an incorrect
context
Kirill Müller
2019-Mar-08 21:26 UTC
[Rd] Ellipsis and dot-dot-number [Re: Dots are not fixed by make.names()]
Hi In addition to the inconsistency in make.names(), the text in ?Reserved seems incomplete: "Reserved words outside quotes are always parsed to be references to the objects linked to in the ?Description?, and hence they are not allowed as syntactic names (see make.names). They **are** allowed as non-syntactic names, e.g. inside backtick quotes." `..1` and `...` are allowed for assigning, but these symbols cannot be used in the context of a variable. Example: `..1` <- 1 `..13` <- 13 `...` <- "dots" `..1` #> Error: ..1 used in an incorrect context, no ... to look in `..13` #> Error: ..13 used in an incorrect context, no ... to look in `...` #> Error in eval(expr, envir, enclos): '...' used in an incorrect context Does the ?Reserved help page need to mention this oddity, or link to more detailed documentation? Best regards Kirill On 05.10.18 11:27, Kirill M?ller wrote:> Hi > > > It seems that names of the form "..#" and "..." are not fixed by > make.names(), even though they are reserved words. The documentation > reads: > > > [...] Names such as ".2way" are not valid, and neither are the > reserved words. > > > Reserved words in R: [...] ... and ..1, ..2 etc, which are used to > refer to arguments passed down from a calling function, see ?... . > > I have pasted a reproducible example below. > > I'd like to suggest to convert these to "...#" and "....", > respectively. Happy to contribute PR. > > > Best regards > > Kirill > > > make.names(c("..1", "..13", "...")) > #> [1] "..1"? "..13" "..." > `..1` <- 1 > `..13` <- 13 > `...` <- "dots" > > mget(c("..1", "..13", "...")) > #> $..1 > #> [1] 1 > #> > #> $..13 > #> [1] 13 > #> > #> $... > #> [1] "dots" > `..1` > #> Error in eval(expr, envir, enclos): the ... list does not contain > any elements > `..13` > #> Error in eval(expr, envir, enclos): the ... list does not contain > 13 elements > `...` > #> Error in eval(expr, envir, enclos): '...' used in an incorrect context > > ______________________________________________ > R-devel at r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-devel
Martin Maechler
2019-Mar-12 11:07 UTC
[Rd] Ellipsis and dot-dot-number [Re: Dots are not fixed by make.names()]
>>>>> Kirill M?ller >>>>> on Fri, 8 Mar 2019 22:26:17 +0100 writes: >>>>> Kirill M?ller >>>>> on Fri, 8 Mar 2019 22:26:17 +0100 writes:> Hi > In addition to the inconsistency in make.names(), the text in ?Reserved > seems incomplete: > "Reserved words outside quotes are always parsed to be references to the > objects linked to in the ?Description?, and hence they are not allowed > as syntactic names (see make.names). They **are** allowed as > non-syntactic names, e.g. inside backtick quotes." > `..1` and `...` are allowed for assigning, but these symbols cannot be > used in the context of a variable. Example: > `..1` <- 1 > `..13` <- 13 > `...` <- "dots" > `..1` > #> Error: ..1 used in an incorrect context, no ... to look in > `..13` > #> Error: ..13 used in an incorrect context, no ... to look in > `...` > #> Error in eval(expr, envir, enclos): '...' used in an incorrect context > Does the ?Reserved help page need to mention this oddity, or link to > more detailed documentation? > Best regards > Kirill I see> `..9` <- 999 > get("..9")[1] 999> `..9`Error: ..9 used in an incorrect context, no ... to look in> `...` <- "3 dots" > `...`Error: '...' used in an incorrect context> get("...")[1] "3 dots">> assign("...", "3 DOTS") > assign("..1", "1st dot arg")So get() works for these, but `...` does not for getting but for assignment. OTOH, assign() works for all, reserved words or not, so that should not count. Honestly, I'm not sure if the current behavior is necessary in some sense or just a coincidence. I do see that the C-internal isValidName() [defined in the grammar: gram.y (=> gram.c)] does say that "..." and "..1" etc are valid names and that's what the C code of make.names() uses. Also, as you know they *are* valid names as one does and should use them unquoted although only to "get" and only inside functions. So, no conclusion from here for now for the latter part. For the first, about your make.names() "inconsistency", I'd say it *is* consistent because e.g. ... can be used without quotes and hence is a valid name (mostly ;-). OTOH, make.names() being used to construct "valid" data frame column names, maybe make.names() could be changed, probably via a new optional logical argument say 'dotsValid = TRUE' which when set to FALSE would also treat '...' and '..1' etc. Unfortunately the code changes needed may be a bit ugly as the consistency between make.names() and {C level} isValidName() would be broken for 'dotsValid = FALSE'. Martin > On 05.10.18 11:27, Kirill M?ller wrote: >> Hi >> >> >> It seems that names of the form "..#" and "..." are not fixed by >> make.names(), even though they are reserved words. The documentation >> reads: >> >> > [...] Names such as ".2way" are not valid, and neither are the >> reserved words. >> >> > Reserved words in R: [...] ... and ..1, ..2 etc, which are used to >> refer to arguments passed down from a calling function, see ?... . >> >> I have pasted a reproducible example below. >> >> I'd like to suggest to convert these to "...#" and "....", >> respectively. Happy to contribute PR. >> >> >> Best regards >> >> Kirill >> >> >> make.names(c("..1", "..13", "...")) >> #> [1] "..1"? "..13" "..." >> `..1` <- 1 >> `..13` <- 13 >> `...` <- "dots" >> >> mget(c("..1", "..13", "...")) >> #> $..1 >> #> [1] 1 >> #> >> #> $..13 >> #> [1] 13 >> #> >> #> $... >> #> [1] "dots" >> `..1` >> #> Error in eval(expr, envir, enclos): the ... list does not contain >> any elements >> `..13` >> #> Error in eval(expr, envir, enclos): the ... list does not contain >> 13 elements >> `...` >> #> Error in eval(expr, envir, enclos): '...' used in an incorrect context >> >> ______________________________________________ >> R-devel at r-project.org mailing list >> https://stat.ethz.ch/mailman/listinfo/r-devel > ______________________________________________ > R-devel at r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-devel