Several structure fields (now) computed in ocda do not yet have a
consumer outside the `.ssp` writer (which shares ocda fields in a
PEG parsable .ssp file). Their addition is to facilitate future
output processing: each representing document structure
information that document output generators of various formats,
such as html, epub, latex, sql and any DOM based / tree-graph
(node based hierarchical) representations, previously had to, or
would have to, work out for themselves based on what ocda offered
(without them).
Computing them (upstream) in ocda once and sharing them (and
providing the .ssp), means that:
- future output formats can start from prepared structure rather
than deriving it;
- existing generators can be simplified to consume them instead
of re-deriving;
- a (dlang) generator could in principle be populated either from
ocda directly or from a `.ssp` file;
- `.ssp` being PEG parsable puts the same prepared structure in
reach of implementations in other languages.
`test/test-abstraction-ssp.sh` the `.ssp` reference regression
test is used to catch regression in ocda including these as yet
unused fields, which otherwise would remain unseen until used by
other output-format consumers. This also is the reason issues now
made easily visible and are being addressed (without issue to
existing output generators).
(assisted by Claude-Code)