Thanks for the tips so far. I have modified the example so that
(a) I do not define an S4 method for print [I use summary instead, which
gets similar treatment in mle as far as I can see]
(b) I do not do use the 'import(methods)' directive [I previously did this
because John Chambers explicitly and as point number 1 stated that this was
required, in his email dated 6th September - actually I seem to get the same
results either way]
Nevertheless I get the same behaviour when trying to access a generic method
defined in one package [barpkg in my example] and imported into a second
package [wazpkg in my example]. If I require() the package I get the
behaviour I expect.
- Giles
#the first bit which is fine------------------
#the .R file for package barpkg
setClass("bar",representation("numeric"))
setMethod("summary",signature(object="bar"),
function(object,...)
{
print("summary method for bar")
summary([EMAIL PROTECTED],...)
}
)
setGeneric("barprint",useAsDefault=print)
setMethod("barprint",signature(x="bar"),
function(x,...)
{
print("barprint method for bar")
print([EMAIL PROTECTED],...)
}
)
#the NAMESPACE file for package barpkg
exportMethods(barprint,summary)
exportClasses("bar")
#in R
> require(barpkg)
Loading required package: barpkg
[1] TRUE
> x <- new("bar",1:5)
> summary(x)
[1] "summary method for bar"
Min. 1st Qu. Median Mean 3rd Qu. Max.
1 2 3 3 4 5
> barprint(x)
[1] "barprint method for bar"
[1] 1 2 3 4 5
>
#now the bit which is has been puzzling to me ------------
#the .R file for package wazpkg
wazsummary <- function(x)
{
summary(new("bar",x))
}
wazbarprint <- function(x)
{
barprint(new("bar",x))
}
#the NAMESPACE file for package wazpkg
import(barpkg)
importMethodsFrom(barpkg)
importClassesFrom(barpkg)
export(wazsummary,wazbarprint)
#in R
> require(wazpkg)
Loading required package: wazpkg
[1] TRUE
> wazbarprint(1:5)
[1] "barprint method for bar"
[1] 1 2 3 4 5
> wazsummary(1:5)
[1] "summary method for bar"
Error in .setMethodsForDispatch(f, fdef, resetMlist) :
Internal error: did not get a valid generic function object for
function "summary"
Error in summary([EMAIL PROTECTED], ...) : S language method selection got an
error when called from internal dispatch for function "summary"
>
#HOWEVER... -----------------------
> require(barpkg)
Loading required package: barpkg
[1] TRUE
> require(wazpkg)
[1] TRUE
> wazbarprint(1:5)
[1] "barprint method for bar"
[1] 1 2 3 4 5
> wazsummary(1:5)
[1] "summary method for bar"
Min. 1st Qu. Median Mean 3rd Qu. Max.
1 2 3 3 4 5
-----------------------------
platform i386-pc-mingw32
arch i386
os mingw32
system i386, mingw32
status
major 1
minor 8.1
year 2003
month 11
day 21
language R
I use the following:
Rcmd install --doc="none" --save wazpkg
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