Re: [Rd] Getting param names of primitives

From: Martin Maechler <>
Date: Wed, 11 Jul 2007 12:28:57 +0200

>>>>> "BDR" == Prof Brian Ripley <> >>>>> on Wed, 11 Jul 2007 05:48:56 +0100 (BST) writes:

>> formals(args(log))
    BDR> $x

    BDR> $base
    BDR> exp(1)

    BDR> gives what formals(log) used to.

(I knew). I've been asking myself several times now, if we should not make
formals() do this automatically.
I know that the change might break some code which has used things like

if(is.null(formals(fun))) {  

  ## treat fun as a primitive function


but I think R has provided is.primitive(.) long enough now so that
we could consider the change.


    BDR> On Wed, 11 Jul 2007, miguel manese wrote:

>> Hi,
>> In the latest R this does not work anymore
>> args <- formals(log)
>> because log is primitive. Is there any other way to get the argument
>> list? I just need the name of the parameter to display some error
>> message about it. I have looked at args() but I can't find anything to
>> extract the argument names from it.
>> Thanks,
>> M. Manese

    BDR> -- 
    BDR> Brian D. Ripley,        
    BDR> Professor of Applied Statistics,
    BDR> University of Oxford,             Tel:  +44 1865 272861 (self)
    BDR> 1 South Parks Road,                     +44 1865 272866 (PA)
    BDR> Oxford OX1 3TG, UK                Fax:  +44 1865 272595

    BDR> ______________________________________________
    BDR> mailing list     BDR> mailing list Received on Wed 11 Jul 2007 - 10:39:38 GMT

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