Re: Typing Ada

[neff@Shasta.STANFORD.EDU (Randy Neff)]

I would like to point out that very complex functional objects are designed
primarily with graphics, namely integrated circuits.   This is done through
a series of different abstractions and hierarchy.   
Abstractions:	Functional blocks
		Logic gates
		Transistors
		Mask rectangles
Hierarchy:	Cells of cells of cells of mask rectangles

In Ada, there is only a single hierarchy mechanism, the package; and only
a single abstraction, the programming language code.

Our research at Stanford with the language Anna (ANNotataged Ada) is 
adding an additional abstraction layer, an implementation independent
functional specification of a package specification.   This is equivalent
to a logic diagram of an IC;  the logic diagram explains how the chip
behaves, but not exactly how it is implemented in transistors or mask 
rectangles.