John,
Thanks very much. As you suggested, this turned out not to have anything to do
with R-devel. Instead, it seemed traceable
to my decision a while back to start require()'ing packages in my .Rprofile, at
least when I removed .Rprofile then my original
code for image methods worked fine in the current version of R-devel. "Ours
not to reason why..."
Roger
url: www.econ.uiuc.edu/~roger Roger Koenker
email rkoen...@uiuc.edu Department of Economics
vox: 217-333-4558 University of Illinois
fax: 217-244-6678 Urbana, IL 61801
On Jul 11, 2014, at 8:35 PM, John Chambers <j...@r-project.org> wrote:
> Roger,
>
> Are you implying that your current code works differently under R-devel than
> with the current release? Nothing I'm aware of would suggest that.
>
> With or without setGeneric() (in either version but the single-argument is
> cleaner), a generic function for image() is created in your package's
> namespace.
>
> If you don't export that function, calls from other functions in your package
> will still get the generic version but calls from outside the package will
> get graphics::image.
>
> Here's an example. In my PkgA I have:
>
> setGeneric("image")
>
> setMethod("image", "A", function(x, ...) message("dummy image for class
> A"))
>
> showStuff <- function() showMethods("image")
>
> In the NAMESPACE, I exported showStuff, but not image.
>
> As a result:
>
>> require(PkgA)
> Loading required package: PkgA
>> image
> function (x, ...)
> UseMethod("image")
> <bytecode: 0x7fa835170b08>
> <environment: namespace:graphics>
>> showMethods("image")
>
> Function "image":
> <not an S4 generic function>
>> showStuff
> function ()
> showMethods("image")
> <environment: namespace:PkgA>
>> showStuff()
> Function: image (package graphics)
> x="A"
> x="ANY"
>
> The methods are visible to code inside PkgA but others see only the S3
> function.
>
> John
>
>
> On Jul 11, 2014, at 11:27 AM, Roger Koenker <rkoen...@illinois.edu> wrote:
>
>> I've installed R-devel
>>
>> R Under development (unstable) (2014-07-09 r66111)
>> Platform: x86_64-apple-darwin13.1.0 (64-bit)
>>
>> and am trying to resolve some problems that I am seeing with my
>> SparseM package. In prior versions I explicitly had:
>>
>> setGeneric("image", function(x, ...) standardGeneric("image"))
>>
>> and then used setMethod to define a method for the class matrix.csr
>> but my reading of the setGeneric manpage suggests that this call to
>> setGeneric need not, and probably should not have this second
>> argument, and indeed, need not exist at all, since the generic is
>> automatically created by the setMethod invocation.
>>
>> However, what is puzzling to me is that in my new R-devel version
>> none of these options have the intended effect of making "image"
>> a generic and allowing R to dispatch for matrix.csr objects. When
>> I omit the setGeneric() call, I do get a message at INSTALL time
>> that a generic for image is being created, but then after loading
>> SparseM:
>>
>>> showMethods(image)
>> Function "image":
>> <not an S4 generic function>
>>
>> On the command line, I can make this work:
>>
>>> setGeneric("image")
>> [1] "image"
>>> showMethods(image)
>> Function: image (package graphics)
>> x="ANY"
>> x="matrix.csr"
>>
>> And -- even more irritating -- if I require(Matrix) then the generic
>> is created together with my method and all the Matrix methods. At
>> the risk of theorizing without data, I suspect that this has something
>> to do with NAMESPACES, and I have tried to follow the setup for
>> Matrix by having:
>>
>> importFrom("graphics", image)
>> exportMethods("image")
>>
>> but clearly I'm still missing some crucial aspect. Any suggestions
>> would be most welcome.
>>
>> Roger
>>
>>
>>
>> url: www.econ.uiuc.edu/~roger Roger Koenker
>> email rkoen...@uiuc.edu Department of Economics
>> vox: 217-333-4558 University of Illinois
>> fax: 217-244-6678 Urbana, IL 61801
>>
>> ______________________________________________
>> R-devel@r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-devel
>
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