checkmate (version 2.3.1)

makeAssertion: Turn a Check into an Assertion

Description

makeAssertion is the internal function used to evaluate the result of a check and throw an exception if necessary. makeAssertionFunction can be used to automatically create an assertion function based on a check function (see example).

Usage

makeAssertion(x, res, var.name, collection)
makeAssertionFunction(
  check.fun,
  c.fun = NULL,
  use.namespace = TRUE,
  coerce = FALSE,
  env = parent.frame()
)

Value

makeAssertion invisibly returns the checked object if the check was successful, and an exception is raised (or its message stored in the collection) otherwise.

makeAssertionFunction returns a function.

Arguments

x

[any]
Object to check.

res

[TRUE | character(1)]
The result of a check function: TRUE for successful checks, and an error message as string otherwise.

var.name

[character(1)]
The custom name for x as passed to any assert* function. Defaults to a heuristic name lookup.

collection

[AssertCollection]
If an AssertCollection is provided, the error message is stored in it. If NULL, an exception is raised if res is not TRUE.

check.fun

[function]
Function which checks the input. Must return TRUE on success and a string with the error message otherwise.

c.fun

[character(1)]
If not NULL, instead of calling the function check.fun, use .Call to call a C function “c.fun” with the identical set of parameters. The C function must be registered as a native symbol, see .Call. Useful if check.fun is just a simple wrapper.

use.namespace

[logical(1)]
Call functions of checkmate using its namespace explicitly. Can be set to FALSE so save some microseconds, but the checkmate package needs to be imported. Default is TRUE.

coerce

[logical(1)]
If TRUE, injects some lines of code to convert numeric values to integer after an successful assertion. Currently used in assertCount, assertInt and assertIntegerish.

env

[environment]
The environment of the created function. Default is the parent.frame.

See Also

Other CustomConstructors: makeExpectation(), makeTest()

Examples

# Simple custom check function
checkFalse = function(x) if (!identical(x, FALSE)) "Must be FALSE" else TRUE

# Create the respective assert function
assertFalse = function(x, .var.name = vname(x), add = NULL) {
  res = checkFalse(x)
  makeAssertion(x, res, .var.name, add)
}

# Alternative: Automatically create such a function
assertFalse = makeAssertionFunction(checkFalse)
print(assertFalse)