check_that
(Package: ensurer) :
Ensure Certain Conditions for a Value at Runtime.
Use ensure_that (imperitive form) to ensure conditions for a value "on the fly". The present tense form, ensures_that is used to make reusable "contracts" (functions) which can subsequently be applied to values; see examples below. It is also possible to check (rather than ensure) whether conditions are satisfied; the check_that function works like ensure_that but will return TRUE or FALSE.