The action

    @assert expression

checks that the result of an expression is true. If not, a message ginvin the location of the faulty assertion is emitted. If the argument evaluates to true, the assertion does nothing.

This action is provided as a facility for debugging and testing, especially with the standalone version of Antescofo. If the standalone runs in strict mode, then the entire program is aborted three seconds after the emission of the localization. Abort never happens in the Max or PD version.