2.  ADL Data types

     Structured	data types are the heart of  any  structured
language.   ADL	is not lacking in structured data types.  It
is through the proper definition of  specific  instances  of
these data types that the ADL programmer defines a scenario.
Note that all data types in ADL	are represented	by  sixteen-
bit integer IDs.  Although there is little facility for	pro-
ducing user-defined data types,	the power  of  the  existing
set  makes  it	unlikely that such would be required for any
reasonable scenario.