The middle way approach for Ada based PDL syntax

This note presents a middle way approach in Ada based PDL syntax. The proposed PDL syntax allows simple syntactic entities like TRW's PDL [1, 2], fully formed constructs like IBM's PDL and any degree of design details between these two extremes.This PDL represents missing design parts in a natural and consistent way by adding the 'not defined yet' lexical element to Ada syntax. This new lexical element consists of any free text enclosed in curly brackets and can replace almost any Ada language construct.