assertions (version 0.3.0)

assert_function_variadic: Assert function is variadic

Description

Assert that a function signature declares the ... argument (variadic arguments).

Usage

assert_function_variadic(
  x,
  msg = NULL,
  call = rlang::caller_env(),
  arg_name = NULL
)

Value

invisible(TRUE) if function x declares ..., otherwise aborts with the error message specified by msg

Arguments

x

a function to check includes ... in its signature

msg

The error message thrown if the assertion fails (string)

call

Only relevant when pooling assertions into multi-assertion helper functions. See cli_abort for details.

arg_name

Advanced use only. Name of the argument passed (default: NULL, will automatically extract arg_name).

Examples

my_fun <- function(x, ...) x
assert_function_variadic(my_fun)

try({
  my_fun_no_dots <- function(x) x
  assert_function_variadic(my_fun_no_dots)
})