[Rd] formals() adds 0 to complex function arguments
peter dalgaard
pdalgd at gmail.com
Sun Jan 19 22:16:16 CET 2014
It's not formals() that is doing you in. Rather, it is a conspiration between two things:
(a) R always displays complex constants as x+yi, even if x is zero and (b) there really is no way to specify complex constants with non-zero real part, i.e. 1+2i is a sum of a real and and imaginary complex constant. You can see the effect already at
> quote(1+2i)
1 + (0+2i)
> q <- quote(1+2i)
> q[[1]]
`+`
> q[[2]]
[1] 1
> q[[3]]
[1] 0+2i
> str(q)
language 1 + (0+2i)
> str(q[[3]])
cplx 0+2i
Someone might want to fix this by implementing a full syntax for complex constants, but meanwhile, I think a passable workaround could be
> formals(test)$a <- 1+2i
> args(test)
function (a = 1+2i)
NULL
> test
function (a = 1+2i)
{
}
Or maybe, less sneaky
Cplx_1plus2i <- 1+2i
test <- function(a = Cplx_1plus2i){}
-pd
On 19 Jan 2014, at 20:45 , baptiste auguie <baptiste.auguie at gmail.com> wrote:
> Dear list,
>
> I'm facing an issue with the automated documentation of a function using
> roxygen2. The function has a complex-valued default argument, which is
> picked up by roxygen2 using formals() to generate the corresponding Usage
> section of the Rd file. Unfortunately, it appears that formals() reformats
> complex numbers. Consider the example below,
>
> test <- function(a = 1+2i){}
>
>> args(test)
> function (a = 1 + (0+2i))
> NULL
>> formals(test)
> $a
> 1 + (0+2i)
>
> As a result, R CMD check issues a warning that my Rd file is inconsistent
> between Code and Docs. Redefining the function with this syntax (a = 1 +
> (0+2i)) doesn't help, as a new 0 gets added to become 1 + (0 + (0+2i)).
>
> Is this reformatting necessary?
>
> Regards,
>
> baptiste
>
> sessionInfo()
> R Under development (unstable) (2013-11-25 r64299)
> Platform: x86_64-apple-darwin10.8.0 (64-bit)
>
> locale:
> [1] en_NZ.UTF-8/en_NZ.UTF-8/en_NZ.UTF-8/C/en_NZ.UTF-8/en_NZ.UTF-8
>
> attached base packages:
> [1] stats graphics grDevices utils datasets methods base
>
> loaded via a namespace (and not attached):
> [1] tools_3.1.0
>
> [[alternative HTML version deleted]]
>
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--
Peter Dalgaard, Professor,
Center for Statistics, Copenhagen Business School
Solbjerg Plads 3, 2000 Frederiksberg, Denmark
Phone: (+45)38153501
Email: pd.mes at cbs.dk Priv: PDalgd at gmail.com
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