R: Assert an argument has known prototype and/or size

vec_assert {vctrs}

R Documentation

Assert an argument has known prototype and/or size

vec_is() is a predicate that checks if its input conforms to a prototype and/or a size.
vec_assert() throws an error when the input doesn't conform.

vec_assert(x, ptype = NULL, size = NULL, arg = as_label(substitute(x)))

vec_is(x, ptype = NULL, size = NULL)

`x`	A vector argument to check.
`ptype`	Prototype to compare against. If the prototype has a class, its `vec_ptype()` is compared to that of `x` with `identical()`. Otherwise, its `typeof()` is compared to that of `x` with `==`.
`size`	Size to compare against
`arg`	Name of argument being checked. This is used in error messages. The label of the expression passed as `x` is taken as default.

vec_is() returns TRUE or FALSE. vec_assert() either throws a typed error (see section on error types) or returns x, invisibly.

If the prototype doesn't match, an error of class "vctrs_error_assert_ptype" is raised.
If the size doesn't match, an error of class "vctrs_error_assert_size" is raised.

Both errors inherit from "vctrs_error_assert".

[Package vctrs version 0.2.2 Index]