> That's two different issues:
>
>> y <- list()
>> y$... <- 2
>> y$..2 <- 3
>> y$break <- 4
> Error: unexpected 'break' in "y$break"
>
> Notice that there is nothing _syntactically_ wrong with ... & friends as
> names:
>
>> quote(...<-4)
> ... <- 4
>
> It's the _evaluator_ that throws the error be
On Jul 6, 2011, at 03:25 , Hadley Wickham wrote:
>> What's wrong with that? They are names alright, just with special meanings.
>
> But you can't really use them for variables:
>
>> ... <- 4
>> ...
> Error: '...' used in an incorrect context
>> ..1 <- 4
>> ..1
> Error: 'nthcdr' needs a list to
> What's wrong with that? They are names alright, just with special meanings.
But you can't really use them for variables:
> ... <- 4
> ...
Error: '...' used in an incorrect context
> ..1 <- 4
> ..1
Error: 'nthcdr' needs a list to CDR down
And make.names generally protects you against that:
> m
On July 5, 2011 04:59:16 PM Hadley Wickham wrote:
> That's not a syntactically valid name - you use backticks to refer to
> names that are not syntactically valid.
I was too loose in my terminology: I meant that `x prime` is a valid name, but
as you said, it is not syntactically valid.
Davor
__
On Jul 6, 2011, at 01:40 , Hadley Wickham wrote:
> On Tue, Jul 5, 2011 at 7:31 PM, steven mosher wrote:
>> regexp approach is kinda ugly
>> http://www.r-bloggers.com/testing-for-valid-variable-names/
>
> Hmm, I think that suggests a couple of small bug in make.names:
>
>> make.names("...")
>
> This is without quoting, right? Because "make.names" replaces spaces with
> periods, and using quoting I can create syntactically valid names that do
> include spaces:
>
> `x prime` <- 3
> ls()
That's not a syntactically valid name - you use backticks to refer to
names that are not syntact
On June 30, 2011 01:37:57 PM Hadley Wickham wrote:
> Is there any easy way to tell if a string is a syntactically valid name?
[...]
>
> One implementation would be:
>
> is.syntactic <- function(x) x == make.names(x)
>
> but I wonder if there's a more elegant way.
This is without quoting, right
regexp approach is kinda ugly
http://www.r-bloggers.com/testing-for-valid-variable-names/
On Tue, Jul 5, 2011 at 3:29 PM, Hadley Wickham wrote:
> > I wouldn't expect so. The basic structure might be handled using a regexp
> of sorts, but even that is tricky because of the "dot not followed by
On Tue, Jul 5, 2011 at 7:31 PM, steven mosher wrote:
> regexp approach is kinda ugly
> http://www.r-bloggers.com/testing-for-valid-variable-names/
Hmm, I think that suggests a couple of small bug in make.names:
> make.names("...")
[1] "..."
> make.names("..1")
[1] "..1"
and
> x <- paste(rep("
> I wouldn't expect so. The basic structure might be handled using a regexp of
> sorts, but even that is tricky because of the "dot not followed by number"
> rule, and then there's the stop list of reserved words, which would make your
> code clumsy whatever you do.
>
> How on Earth would you ex
On Jun 30, 2011, at 22:37 , Hadley Wickham wrote:
> Hi all,
>
> Is there any easy way to tell if a string is a syntactically valid name?
>
> e.g.
>
> is.syntactic("X123")
> # TRUE
> is.syntactic("[[")
> # FALSE
>
> One implementation would be:
>
> is.syntactic <- function(x) x == make.names(
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