For information on converting to InterSystems IRIS, see the
InterSystems IRIS Adoption Guide
and the InterSystems IRIS In-Place Conversion Guide,
both available on the WRC Distributions page (login required).
Tests if the logical value %val, which is an integer value, is valid.
The validation is based on the class parameter settings used
for the class attribute this data type is associated with.
In this case, MAXVAL and MINVAL.