1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
|
\name{on_failure}
\alias{on_failure}
\alias{on_failure<-}
\title{Custom failure messages for assertions.}
\usage{
on_failure(x)
on_failure(x) <- value
}
\arguments{
\item{x}{a assertion function that returns \code{TRUE} if
the assertion is met, \code{FALSE} otherwise.}
\item{value}{a function with parameters \code{call} and
\code{env} that returns a custom error message as a
string.}
}
\description{
Custom failure messages for assertions.
}
\examples{
is_odd <- function(x) {
assert_that(is.numeric(x), length(x) == 1)
x \%\% 2 == 1
}
see_if(is_odd(2))
on_failure(is_odd) <- function(call, env) {
paste0(deparse(call$x), " is even")
}
see_if(is_odd(2))
}
|
