The example is invoking NextMethod via an anonymous function, which is not allowed (see documentation for NextMethod). Normally one gets a runtime error "'NextMethod' called from an anonymous function", but not here as the anonymous function is called via do.call. I will fix so that there is a runtime error in this case as well, thanks for uncovering this problem.
I don't think there is a way to replace (unnamed) arguments in dots for NextMethod.
Tomas On 02/21/2018 02:16 PM, Iñaki Úcar wrote:
I've set up a repo with a reproducible example of the issue described in my last email: https://github.com/Enchufa2/dispatchS3dots Iñaki 2018-02-20 19:33 GMT+01:00 Iñaki Úcar <i.uca...@gmail.com>:Hi all, Not sure if this belongs to R-devel or R-package-devel. Anyways... Suppose we have objects of class c("foo", "bar"), and there are two S3 methods c.foo, c.bar. In c.foo, I'm trying to modify the dots and forward the dispatch using NextMethod without any success. This is what I've tried so far: c.foo <- function(..., recursive=FALSE) { dots <- list(...) # inspect and modify dots # ... do.call( function(..., recursive=FALSE) structure(NextMethod("c"), class="foo"), c(dots, recursive=recursive) ) } foobar <- 1 class(foobar) <- c("foo", "bar") c(foobar, foobar) Error: C stack usage 7970788 is too close to the limit There's recursion (!). But the funniest thing is that if c.foo is exported by one package and c.bar is exported by another one, there's no recursion, but c.bar is never called (!!). Why is the same code behaving in a different way depending on whether these functions are defined in the .GlobalEnv or in two attached packages? (BTW, isS3method() is TRUE, for c.foo and c.bar in both cases). I'm blocked here. Am I missing something? Is there a way of doing this? Thanks in advance. Regards, Iñaki
______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
