A “To Be Determined” package for Ada development

This paper illustrates how the Ada language supports simple and convenient techniques for maintaining the syntactic and semantic validity of unfinished designs, thereby enabling designers and implementors of software systems to benefit from the consistency checking that an Ada compiler performs on its libraries well before that would otherwise be possible. It is asserted that this capability is likely to be particularly useful for large systems development. Both a rationale for and a concrete example of an Ada package which supports the techniques are provided.