Allen McIntosh wrote:
> Seth Falcon wrote:
>
>> Allen McIntosh <[EMAIL PROTECTED]> writes:
>>
>>> Is it possible to override S4 methods in an installed package?
>>> The naive
>>> library("pkg")
>>> setMethod("foo", signature(obj = "bar"),
>>> function(obj , x, y) { new definition }
>>> , where="package:pkg")
>>> results in the error
>>> Error in setMethod("foo", signature(obj = "bar"), function(obj, :
>>> the environment "pkg" is locked; cannot assign methods for function
>>> "foo"
>>>
>> If foo is a generic that you are calling directly, then you can
>> probably define it in the global environment (omit the where arg) and
>> test it that way.
>>
>> OTOH, if foo is used by pkg internally, then it will be much easier to
>> simply edit the source for pkg, reinstall and test. If you find and
>> fix a bug, most package maintainers will be quite happy to integrate
>> your fix.
>>
>
> Thanks for the suggestion. Unfortunately, foo() uses internal
> functions. When foo() is defined in the global environment, these are
> not visible.
>
I think you can set the environment of your method to see the package
internals. Those internals won't see your method, though.
To do this, you'd do something like
newfoo <- function(obj , x, y) { new definition }
environment(newfoo) <- environment(foo) # or some other function from
the package
setMethod("foo", signature(obj = "bar"),
newfoo)
> I was hoping to avoid recompiling and installing under Windows. Looks
> like I may not have a choice.
>
This is getting easier: we're down to a single install, as long as you
don't need all possible formats of man pages.
Duncan Murdoch
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