vld_error_msg: Get or set a validation error message

In egnha/rong: Functional Input Validation

Description

Get or set a validation error message

Usage

vld_error_msg(f)

vld_error_msg(f, env = parent.frame()) <- value

new_vld_error_msg(msg, env = parent.frame())

Arguments

f	Predicate function.
env	Environment that is in scope when a {{...}} substring of the error message is interpolated.
value	Error message (string or quosure of a string).
msg	Error message (string).

Details

An error message can only be set for predicate functions that are closures. To set an error message of a primitive predicate, e.g., is.array(), transform it to a closure with rlang::as_closure().

Value

Quosure of a string.

Examples

is_integer <- rlang::as_closure(is.integer)
vld_error_msg(is_integer) <- "{{.}} not of integer type (type: {typeof(.)})"
vld_error_msg(is_integer)

foo <- firmly(identity, is_integer)
foo(1:3)
## Not run: 
foo(runif(3))
## End(Not run)

is_integer <- rlang::is_integer
msg <- local({
  len <- function(n) if (is.null(n)) "" else paste(" of length", n)
  new_vld_error_msg("{{.}} is not an integer vector{{len(.value$n)}}")
})
vld_error_msg(is_integer) <- msg

foo <- firmly(identity, is_integer(n = 3))
foo(1:3)
## Not run: 
foo(1:2)
## End(Not run)

egnha/rong documentation built on May 7, 2019, 9:48 p.m.