chkDots: Warn About Extraneous Arguments in the "..." of Its Caller
In robertzk/monadicbase: The R Base Package

Description Usage Arguments Author(s) See Also Examples

Warn about extraneous arguments in the ... of its caller. A utility to be used e.g., in S3 methods which need a formal ... argument but do not make any use of it. This helps catching user errors in calling the function in question (which is the caller of chkDots().

1	chkDots(..., which.call = -1, allowed = character(0))

`...`	“the dots”, as passed from the caller.
`which.call`	passed to `sys.call()`. A caller may use -2 if the message should mention its caller.
`allowed`	not yet implemented: character vector of named elements in `...` which are “allowed” and hence not warned about.

Martin Maechler, first version outside base, June 2012.

warning, ....

seq.default ## <- you will see  ' chkDots(...) '

seq(1,5, foo = "bar") # gives warning via chkDots()

## warning with more than one ...-entry:
density.f <- function(x, ...) NextMethod("density")
x <- density(structure(rnorm(10), class="f"), bar=TRUE, baz=TRUE)