CATCH CAT CAT`
CATCH
* CATCH ( xt -- 0|n )

execute the given execution-token and catch
any exception that can be caught therein.
software can arbitrarily raise an exception
using THROW - the value 0 means there
was no exception, other denote implementation
dependent exception-codes.

FORTH/ANS exception (dpANS9.6.1.0875) ordinary primitive