These functions are soft-deprecated, please use is_call() and its n argument instead.

is_lang(x, name = NULL, n = NULL, ns = NULL)

is_unary_lang(x, name = NULL, ns = NULL)

is_binary_lang(x, name = NULL, ns = NULL)




An object to test. If a formula, the right-hand side is extracted.


An optional name that the call should match. It is passed to sym() before matching. This argument is vectorised and you can supply a vector of names to match. In this case, is_call() returns TRUE if at least one name matches.


An optional number of arguments that the call should match.


The namespace of the call. If NULL, the namespace doesn't participate in the pattern-matching. If an empty string "" and x is a namespaced call, is_call() returns FALSE. If any other string, is_call() checks that x is namespaced within ns.


A quosure to test.