I.e., layering is, IMO at least, a model. Fine for describing things, but
not necessarily a good blueprint for an implementation.
compilation systems can be constructed which will procuce efficient inlined
code for nicely modularized (layered) source. just not for programs which
use type-free pointers and similar analysis-defeating features.
Also seems to be a good electric fence - you can cross layers, but very
carefully.
try reading my message again, the one with >> above. i was NOT suggesting
crossing layers at all, but in fact, suggesting why one does not need to.
randy