R: Warn About Extraneous Arguments in the "..." of Its Caller

chkDots {base}

R Documentation

Warn About Extraneous Arguments in the "..." of Its Caller

Description

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()).

Usage

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

Arguments

`...`	“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.

Author(s)

Martin Maechler, first version outside base, June 2012.

Examples

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)