[Rd] as.POSIXct/as.POSIXlt generics

[Sklyar, Oleg (MI London)]

Hi,

I am trying to define the as.POSIXct as an S4 method for one of my
classes. Trying to define a generic, I am getting an error that it is
already differently defined in base. However, if I query for it, there
is no definition. Being in base, I also cannot really import it. If I
define methods without definig a generic, they will work but with a
warning that a new generic will be automatically created. See the code
chunk below. Any idea how to make it work w/o warnings?

All the same for as.POSIXlt.

Using S3 definition instead works for the parent class, but seems to
require an additional definition for derived ones, well, I'd rather
avoid S3.

Thanks, Oleg

Help page definition: 

> ?as.POSIXct
Usage:
as.POSIXct(x, tz = "")

osklyar:R > R
*** R version 2.6.2 (2008-02-08) ***
> getGeneric("as.POSIXct")
NULL

> setGeneric("as.POSIXct", function(x, tz)
standardGeneric("as.POSIXct"))
New generic for "as.POSIXct" does not agree with implicit generic from
package "base"; a new generic will be assigned with package ".GlobalEnv"
[1] "as.POSIXct"

osklyar:R > R
*** R version 2.6.2 (2008-02-08) ***
> source("TimeDate.R")
Creating a new generic function for "as.POSIXct" in ".GlobalEnv"
Creating a new generic function for "as.POSIXlt" in ".GlobalEnv"

The latter executes: setMethod("as.POSIXct", w/o setGeneric

> sessionInfo()
R version 2.6.2 (2008-02-08)
x86_64-unknown-linux-gnu

locale:
LC_CTYPE=en_GB.UTF-8;LC_NUMERIC=C;LC_TIME=en_GB.UTF-8;LC_COLLATE=C;LC_MO
NETARY=en_GB.UTF-8;LC_MESSAGES=en_GB.UTF-8;LC_PAPER=en_GB.UTF-8;LC_NAME=
C;LC_ADDRESS=C;LC_TELEPHONE=C;LC_MEASUREMENT=en_GB.UTF-8;LC_IDENTIFICATI
ON=C

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base

Dr Oleg Sklyar
Technology Group
Man Investments Ltd
+44 (0)20 7144 3803
osklyar at maninvestments.com


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