OCCAM-equivalent syntax with pure singleton descent structure

Minor corrections and semantically valid restrictions, and one significant but equivalent change, allow the occam 2.0 syntax to be expressed in a yacc-compatible syntax (actually flex and bison are used) with very desirable properties. A rich 13-level descent structure (descent happens when a syntactic object is part of a definition of another syntactic object) is all singletons except for two levels (one equivalent to expression and the other equivalent to process), and these are broken up themselves into singletons by extended descent (parenthesis plus square bracket enclosure count, and indentation count, respectively). This will allow formal proofs of syntactic object behavior, and hence whole language behavior, to be vastly simplified.