R: Make assertions

assert {pkgutils}

R Documentation

Make assertions

Description

A function similar to stopifnot reporting more details on vector elements.

Usage

  assert(cond, orig, msg, quiet = FALSE, ...)

Arguments

`cond`	A logical vector, character scalar or function. If a character scalar, converted to a function with `match.fun`. If a function, `orig` is passed to it as its first argument. The function should return a logical vector of the length of `orig`. Contained `NA` values, if any, are replaced by `FALSE`.
`orig`	Mandatory if `cond` is (the name of) a function, otherwise ignored when empty or missing. Otherwise a vector of the length of `cond` if `cond` is a logical vector, or the single argument of `cond` if it is (the name of) a function.
`msg`	When empty or missing, an error message is constructed automatically in the case of failure. Otherwise either are `sprintf` template to be applied to the failing elements of `orig`, or a character scalar directly providing the error message.
`quiet`	Logical scalar determining the type of output in case of success (i.e., all values of `cond` are `TRUE`) or failure. FALSE `TRUE` is returned when successful, an error is raised otherwise. NA `cond` is returned or the resulting logical vector when `cond` is (the name of) a function. In case of failure, a warning is issued. This can be used to drop parts of objects such as data frames, with a warning. TRUE A character vector with the descriptions of the problems is returned. This vector is empty in case of success.
`...`	Optional arguments passed to `cond` when it is (the name of) a function.

Details

Compared to stopifnot this function can only conduct a test on a single object but can report element-specific details of failures.

Value

The type of return value depends on the values of quiet and cond.

Examples

stopifnot(assert(function(x) x > 0, 1:10))
(x <- try(assert(function(x) x > 0, -1:8), TRUE))

## [1] "Error : assertion 'function(x) x > 0' failed for '-1'\nassertion 'function(x) x > 0' failed for '0'\n"
## attr(,"class")
## [1] "try-error"
## attr(,"condition")
## <simpleError: assertion 'function(x) x > 0' failed for '-1'
## assertion 'function(x) x > 0' failed for '0'>

stopifnot(inherits(x, "try-error"))

[Package pkgutils version 0.7.63 Index]