assert_engine: Throws an error if a condition isn't met.
Description
The workhorse of the package. If a condition isn't met,
then an error is thrown.Usage
assert_engine(x, predicate, msg, what = c("all", "any"),
...)Arguments
x
Input to check. If missing, pass no args to
predicate.
predicate
Function that returns a logical value
(possibly a vector).
msg
The error message, in the event of failure.
what
Either 'all' or 'any', to reduce vectorised
tests to a single value.
...
Passed to the predicate function.
Value
FALSE with the attribute message, as
provided in the input.