R devel - Nov 2007 - namespace crash on S3method("as.ff",function)

Dear all,

I have defined a generic as.ff(x, ...) and a method as.ff.function(x, ...) which
converts a standard R function x into a chunked version operating on large ff
objects. Everything works fine, but when registering

S3method("as.ff",function)

in NAMESPACE, the installation fails with some kind of parsing error:

  adding build stamp to DESCRIPTION
  installing NAMESPACE file and metadata
Fehler in parse(nsFile) : Unerwartetes ')' bei
348:
349: S3method("as.ff",function)
Calls: <Anonymous> -> parseNamespaceFile -> parse
Ausf?hrung angehalten
make[2]: *** [nmspace] Error 1
make[1]: *** [all] Error 2
make: *** [pkg-ff] Error 2
*** Installation of ff failed ***

Is this a bug? Any ideas?

Best regards


Jens


P.S. with as.ff() we can do things like
ffx <- as.ff(x) # as.ff.default() turns a standard R object into an ff object
stored on disk
as.ff(log)(ffx) # as.ff.function() turns 'log' into a function that we
can call on ffx: taking the log of an almost arbitrarily large object

> version
               _                           
platform       i386-pc-mingw32             
arch           i386                        
os             mingw32                     
system         i386, mingw32               
status                                     
major          2                           
minor          6.0                         
year           2007                        
month          10                          
day            03                          
svn rev        43063                       
language       R                           
version.string R version 2.6.0 (2007-10-03)

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On 11/5/2007 7:41 AM, Jens Oehlschl?gel wrote:
> Dear all,
> 
> I have defined a generic as.ff(x, ...) and a method as.ff.function(x, ...)
which converts a standard R function x into a chunked version operating on large
ff objects. Everything works fine, but when registering
> 
> S3method("as.ff",function)
> 
> in NAMESPACE, the installation fails with some kind of parsing error:
> 
>   adding build stamp to DESCRIPTION
>   installing NAMESPACE file and metadata
> Fehler in parse(nsFile) : Unerwartetes ')' bei
> 348:
> 349: S3method("as.ff",function)
> Calls: <Anonymous> -> parseNamespaceFile -> parse
> Ausf?hrung angehalten
> make[2]: *** [nmspace] Error 1
> make[1]: *** [all] Error 2
> make: *** [pkg-ff] Error 2
> *** Installation of ff failed ***
> 
> Is this a bug? Any ideas?
"function" is a reserved keyword for the parser.  Even though you
don't
execute a NAMESPACE file, it's parsed by the standard parser, and that's
causing the problem.  (You couldn't have a function call that looked 
like that without a parse error, either.)

I don't have time to explore this today, but what I'd do is try

S3method("as.ff", `function`)

or

S3method("as.ff","function")

first, and if those don't fix it and you don't get a better suggestion, 
then report this as a design bug.

Duncan Murdoch
> Best regards
> 
> 
> Jens
> 
> 
> P.S. with as.ff() we can do things like
> ffx <- as.ff(x) # as.ff.default() turns a standard R object into an ff
object stored on disk
> as.ff(log)(ffx) # as.ff.function() turns 'log' into a function that
we can call on ffx: taking the log of an almost arbitrarily large object
> 
> 
>> version
>                _                           
> platform       i386-pc-mingw32             
> arch           i386                        
> os             mingw32                     
> system         i386, mingw32               
> status                                     
> major          2                           
> minor          6.0                         
> year           2007                        
> month          10                          
> day            03                          
> svn rev        43063                       
> language       R                           
> version.string R version 2.6.0 (2007-10-03)
>

On Mon, 5 Nov 2007, "Jens Oehlschl?gel" wrote:
> Dear all,
>
> I have defined a generic as.ff(x, ...) and a method as.ff.function(x, ...)
which converts a standard R function x into a chunked version operating on large
ff objects. Everything works fine, but when registering
>
> S3method("as.ff",function)
>
> in NAMESPACE, the installation fails with some kind of parsing error:
>
>  adding build stamp to DESCRIPTION
>  installing NAMESPACE file and metadata
> Fehler in parse(nsFile) : Unerwartetes ')' bei
> 348:
> 349: S3method("as.ff",function)
> Calls: <Anonymous> -> parseNamespaceFile -> parse
> Ausf?hrung angehalten
> make[2]: *** [nmspace] Error 1
> make[1]: *** [all] Error 2
> make: *** [pkg-ff] Error 2
> *** Installation of ff failed ***
>
> Is this a bug? Any ideas?
You need to quote "function".  It falls under

   (Note that variable names may be quoted, and non-standard names such as
   @code{[<-.fractions} must be.)

since reserved words cannot be standard names.  But it could stand being 
spelt out in R-exts.

There are examples in package 'utils'.

-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595