[Rd] rep fails on pairlist

[Gabor Grothendieck]

On Thu, Jul 26, 2012 at 7:29 PM, Duncan Murdoch
<murdoch.duncan at gmail.com> wrote:
> On 12-07-26 3:55 PM, Gabor Grothendieck wrote:
>>
>> This code which has worked for years in R but fails under R-devel:
>>
>>> R.version.string
>>
>> [1] "R Under development (unstable) (2012-07-25 r59963)"
>>>
>>>
>>> n <- 3
>>> f <- function(x) {}
>>> formals(f) <- rep(formals(f), n) ##
>>
>> Error in rep(formals(f), n) : replication of pairlists is defunct
>>
>> The message suggests that the change was intentional.
>> Why was this functionality removed?
>> What code should be used in its place?
>>
>>
>
> rep() on a pairlist didn't return a pairlist, it coerced to a list and then
> rep'd that.  So you could do the same explicitly if that's what you really
> want:
>
> formals(f) <- rep(as.list(formals(f)), n)
>
> This works because the formals<- code is forgiving; other uses of pairlists
> would not accept the result of rep on a pairlist.
>

Thanks. I will use that instead.

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