Using
jml <- function(...) UseMethod("jml")
will do.
/Henrik
On Wed, Nov 11, 2009 at 4:26 PM, Doran, Harold <hdo...@air.org> wrote:
> I have constructed the following functions and need a little clarification:
>
> ### function to fit the model parameters
> jml.fit <- function(dat, con = 1e-3, bias=FALSE, ...){
> do stuff ...
> }
>
> ### default function which calls jml.fit
> jml.default <- function(dat, con = 1e-3, bias=FALSE, ...){
> result <- jml.fit(dat, con = 1e-3, bias)
> result$call <- match.call()
> class(result) <- "jml"
> result
> }
>
> ### Function to make use of formula
> jml.formula <- function(formula, data, na.action, subset, ...){
> mf <- match.call(expand.dots = FALSE)
> m <- match(c("formula", "data", "na.action", "subset"), names(mf), 0L)
> mf <- mf[c(1L, m)]
> mf$drop.unused.levels <- TRUE
> mf[[1L]] <- as.name("model.frame")
> mf <- eval(mf, parent.frame())
> mt <- attr(mf, "terms")
> dat <- mf
> result <- jml.default(dat, ...)
> result$call <- match.call()
> result$formula <- formula
> result
> }
>
> ### and the generic function
> jml <- function(dat, con = 1e-3, bias=FALSE, ...) UseMethod("jml")
>
> Writing R Extensions states, "If the generic specifies defaults, all methods
> should use the same defaults."
>
> In my example above, the generic function has 2 defaults: one for argument
> con and another bias. I'm a little confused on exactly how the generic
> function should be structured for proper package development.
>
> I think the options are:
>
> 1) jml <- function(dat, con = 1e-3, bias=FALSE, ...) UseMethod("jml")
> 2) jml <- function(x, con = 1e-3, bias=FALSE, ...) UseMethod("jml")
> 3) jml <- function(formula, data, na.action, subset, con = 1e-3, bias =
> FALSE, ...) UseMethod("jml")
>
> I'm inclined to believe #3 is correct because the .Rd page needs to reflect
> the args in this function, is that right? Then, this generic function would
> include the formula, data, na.action, and subset and it includes the proper
> defaults as the other functions.
>
> Thank you
> Harold
>
>> sessionInfo()
> R version 2.10.0 (2009-10-26)
> i386-pc-mingw32
>
> locale:
> [1] LC_COLLATE=English_United States.1252 LC_CTYPE=English_United States.1252
> [3] LC_MONETARY=English_United States.1252 LC_NUMERIC=C
> [5] LC_TIME=English_United States.1252
>
> attached base packages:
> [1] stats graphics grDevices utils datasets methods base
>
> other attached packages:
> [1] scoreFoo_1.1 MiscPsycho_1.4 statmod_1.4.1
>
> loaded via a namespace (and not attached):
> [1] tools_2.10.0
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