Yes, there's a change from R 2.6.2 to 2.7.0 that might have been unintended and hence a bug. The short version is this
setClassUnion("OptionalPOSIXct", c("POSIXct", "NULL")) as(Sys.time(), "OptionalPOSIXct", strict=FALSE) which now gives >> Error .. >> no method or default for coercing "POSIXt" to "OptionalPOSIXct and used to work in 2.6.2. Unfortunately, the expert master mind on these issues, John Chambers, is basically offline these days, and I'd rather have waited on his opinion on the issue. Class unions are a bit special and from that may have been quite untested. Excuse me, but why did you not find this when beta or even alpha testing R 2.7.0? We now have always 2 weeks of alpha testing and 1+1 week of beta testing before an x.y.0 release, *EXACTLY* in order to find such issues in time and discuss about them {and John was around then ...} Best regards (all the same ;-), Martin >>>>> "PaulG" == Paul Gilbert <[EMAIL PROTECTED]> >>>>> on Wed, 23 Apr 2008 11:01:21 -0400 writes: PaulG> Something has changed in the S4 default for coercing. Am I now suppose PaulG> to use setAs, or is there something else I should do to make this work: PaulG> R version 2.7.0 (2008-04-22) PaulG> .... >> require("methods") >> setClassUnion("OptionalPOSIXct", c("POSIXct", "NULL")) PaulG> [1] "OptionalPOSIXct" >> setClass("TSmetax", PaulG> representation(serIDs="character", ExtractionDate="OptionalPOSIXct" )) PaulG> [1] "TSmetax" >> setGeneric("TSmetax", def= function(x, ...) standardGeneric("TSmetax")) PaulG> [1] "TSmetax" >> setMethod("TSmetax", signature(x="character"), definition= PaulG> function(x, ...){ PaulG> new("TSmetax", serIDs=x, ExtractionDate=Sys.time()) } ) PaulG> [1] "TSmetax" >> z <- new("TSmetax", serIDs="whatever", ExtractionDate= Sys.time()) PaulG> Error in as(slotVal, slotClass, strict = FALSE) : PaulG> no method or default for coercing "POSIXt" to "OptionalPOSIXct" PaulG> (It did work in R-2.6.2.) PaulG> Paul ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel