A plain-text output that keeps the object numbers, written as CommonMark
with GFM pipe tables, one .md per document-language in <lang>/markdown/,
(linked from the metadata page) with images into that shared directory
itself, skipping any already there, so --markdown alone still gives a complete tree.

provided as an alternative to --text rather than a replacement

--markdown  produces a document that renders, (both provide objext
  numbering survives both. Every object carries an anchor and a
  superscript number linking to itself, so a citation by object number
  is a link in any markdown renderer.
--text may still be of value to read in a terminal

A note is written where it is referenced, with a link back to the
object it came from, rather than gathered into an endnotes
section.

(assisted by Claude-Code)

typst provides a new pdf build path replacing latex as the primary pdf
builder.
  --typst (--typ) writes the .typ;
  --pdf writes the .typ and compiles it by spawning `typst compile`.
    (--pdf is redefined, being typst to pdf rather than latex).
  --latex is unchanged and writes the .tex;

One .typ per document-language (not one per paper size). The paper and
the orientation are read from sys.inputs with a default, so the same
file compiles to every paper --set-papersize asks for, the pdfs keep
their original names.

Spine's paper names (derived from what suited latex) and typst's are
different vocabularies and are mapped; a paper typst does not have is
named and skipped.

With the flag --pdf spine invokes a typesetter to generate the pdf
output directly, which is new (the latex path writes a .tex and leaves
xelatex to the caller). If typst is not available on the machine it is
reported absent, naming the binary and printing the command, and the run
continues, the .typ is written.

Several useful features of an object-centric pdf are easily met, usually
being a few lines each.
- The object number goes in the margin as one `place` at a coordinate
  inside the object's own block, carrying the label every citation
  points at.
- A note is a real footnote at the point of reference, with the
  document's own number and one link back to the object.
- The table of contents locates by object number rather than by page, so
  it holds true across every paper and every setting.

That typst compiles silently across the sample set means every internal
link in every document resolves (--pdf over the collection with two
paper sizes gives 144 pdfs, none skipped and none failed, each the page
size its name claims and each tagged).

paths: .typ, pdf named in same way as .tex based built pdfs so site
linkage works either way

flake.nix: added a typst dev shell, for .typ pdf typesetter
- dsh-typst-pdf providing a pdf typsetter for spine's .typ.
- dsh-latex-pdf provides xelatex for .tex which can still be written.

(assisted by Claude-Code)

flags names tidied so that each names the artefact it acts on.

--ocda-db and --abstraction-db do the same thing. --ocda-db is the
official flag (--abstraction-db remains but undocumented)

--db-round-trip becomes --ocda-db-round-trip, so that it agrees with
--ssp-round-trip: each names the artefact it reads rather than one
naming a container and the other a format.

--abstraction-source is untouched named after he stage as it takes .sst,
a pod, .ssp or .ocda.db, rather than any one artefact.

(assisted by Claude-Code)

spine automatically builds some segments, including: (toc, endnotes,
glossary, bibliography, bookindex, blurb, _the_title) these are now
identified as reserved names and a user is now warned if any of these
names have been manually assigned to a heading by markup. A document
still builds but to disambiguate the ocn of the heading is attached to
the markup (reserved) name and this is seeded before a document not
after. It is read off the finished abstraction rather than reported by
the parser, and beside the ocn alignment check for the same reason: it
is a statement about a document rather than a step in building one.

  WARNING reserved segment name: the_autonomous_contract... [en]
    heading 1 at ocn 135 asks for "endnotes", which spine gives its
    own generated section
      it is named "endnotes-135" instead; ...

A warning: the document is correct and complete and the name it ends
up with works.

--strict makes it a failure for the run, as it does for ocn alignment,
and by the same reasoning: the outputs are written and can be looked at,
and the exit status is taken at the end.

Two of the thirty-six sample documents have reserved segment names,
"1~endnotes" heading. Output is unchanged: nothing here touches the
abstraction.

(assisted by Claude-Code)

need a character to split filenames on in certain circumstances.
there problems with use of a colon in filenames, which is legal on posix
but not on Windows."~" fits the bill better being legal on every
filesystem of interest and is unreserved in rfc 3986, needing no escaping in a url.

The reference abstraction is renamed, its content unchanged. Over
the sample collection two filenames move and nothing else does: the
abstraction and database digests are identical, the archive's
members and their sizes are unchanged, and only the member order
shifts, "~" collating after letters where ":" sorted before them. The
document's epub dc:identifier is a v5 uuid derived from the uid, so it
changes for those filenames.

Every document's uid changes in the search database (spine.search.db).

(assisted by Claude-Code)

--help now names the five source forms before the options, and after
them states the contract: what a .ssp and a .ocda.db each carry and do
not, that both record the digest of the markup they were built from,
which five actions need that markup and what happens when they cannot
have it, and the three ways to verify.

And the version, 0.24.1 to 0.25.0, for abstraction format 2.0 and what
it made possible: (one database per document holding every language of
it, carrying the markup, images, configuration, manifest and
translation catalogues it was built from, with the implications that
carries)

(assisted by Claude-Code)

ensure that db uses the names it carries in manifest which produce
deterministic output (and fix divergence in db rendering of output
names, (which previously also looked for variable input from the
environment))

Output built from a database with --config naming the site configuration
is now byte identical to output built from the pod, on the render route
as it already was on the materialise route.

(assisted by Claude-Code)

dr_document_make in three identifier spellings becomes document_make,
which is what the file has been called since the rename.

The mixin import audit, a template declares its imports at template
scope and they are then visible in every scope it is mixed into (which
is how a template-level split once hijacked a UFCS lookup in code that
had not been touched). Disabling htmlSnippet's imports and rebuilding
names the consumers that were relying on them rather than on their own:
across twelve mixin sites, exactly one. metadata.d now imports the `to`
it uses. The templates keep their imports, their own functions needing
them, and narrowing those is a change of its own rather than a cleanup.

And the standing FIX in source_pod.d: the insert digest line for a non
pod source recorded the insert's path, where every other line in
digests.txt is a filename and a digest naming a file that is not in
the pod under that name cannot be checked against it.

(assisted by Claude-Code)

does this spine still produce this abstraction?

A database states an abstraction and carries the markup it was built
from, so re-parsing the one and comparing against the other says whether
the two still agree. Checked as follows:
- automatically and unskippably when a document is built from a
  database, at the moment it is parsed and before anything has been
  written from it.
- on --ocda-verify=<file>, an action of its own that materialises,
  parses every language, compares, reports and writes nothing, the exit
  status being the answer.
- on --no-verify as the escape, warning per document, for a newer spine
  reading an older artefact where the abstraction is expected to differ
  and the output is wanted anyway.

A build ends at the first failure rather than skipping the language.

A document rebuilt from a database now has its whole abstraction built.

(assisted by Claude-Code)

actions requiring source first materialise the pod

One route per argument, decided by what was asked for. --source, --pod,
--pod2, --show-abstraction and --ocda-db need original markup, so an
.ocda.db given with any of them is written back out as a pod and parsed.
Asked only to render, it is read as an abstraction as before.

To ensure consistency, where a pod is materialized by an argument, that
pod is used for the whole run, including for html and epub that could
have been built from the loaded abstraction instead.

--show-abstraction and --ocda-db join the markup side deliberately.
They could be satisfied by re-serialising the abstraction already
loaded, and were. But an artefact is a statement about the source:
written from a loaded abstraction it says only that the loader is
self consistent, where written from the markup it says what this
spine (whatever current version) makes of that document today.

The chain is checkable against itself: --ocda-db from a database now
goes database, pod, parse, database, and returns the same 9,908,224
bytes it started from. --show-abstraction likewise re-emits the .ssp
files byte for byte.

A .ssp carries no markup by construction and a database written
before the format carried it has none, so both are refused for those
actions, once and by name, and the rest of the run goes on.

(assisted by Claude-Code)