epiphany/crates
Levi Neuwirth fdb4a57885 Text Projection: the operation layer, and the tests that can see it fail
Projection and strict parse for the whole Chapter-6 operation vocabulary: the 31
kind productions, the envelope with its stamp and causal context, the four
payload variants, and the sub-vocabularies for actions, undo policies, tuplet
compensation, cross-cutting values and position remapping. Written against the
grammar, per `req:textproj:operation-vocabulary`, calling `TextValue` only where a
production says `value`.

Names are generated, never spelled: `OperationKindTag::catalog_name()` comes from
the same vocabulary macro as the wire discriminant and the decoder, and `parse`
dispatches through an exhaustive match, so a kind added to the vocabulary and not
to the projector fails to compile.

Six sequences are order-constrained because their encoders normalize. Both halves
of each are enforced and both halves are tested, which turned out to matter. The
rejecting half was straightforward -- `TransposeOp.targets` mirrors the frozen
multiset exactly, rejecting a strict decrease while accepting a duplicate, and
getting that backwards would silently break a frozen operation's replay. The
*normalizing* half was written correctly by every agent and tested by none: every
fixture was already sorted, so all five outbound sorts survived deletion with the
suite green. The consequence was real -- with one removed, the projector emits
descending targets that its own parser then rejects, and that disagree with the
canonical bytes.

`textproj_conformance.rs` closes that. Each of the five builds a value unsorted in
memory, asserts the fixture pair really is descending before relying on it, then
checks the projection sorts, parses, and matches what encode-then-decode produces
-- pinning text and bytes to one normalization rather than merely to each other.

It also carries a structural injectivity sweep: 3319 mutants of projected
envelopes, of which 259 parse, all re-projecting byte-identically. That is
`req:textproj:roundtrip`'s second equation, and it is the evidence that no
whole-line re-project guard is needed -- every path that could normalize is
pre-empted by a per-site check. The sweep asserts its own reach, because one that
rejected everything would prove nothing. Deleting any per-site order check makes
it fail independently of the dedicated test.

And it locks the companion's worked example byte-for-byte. It was correct and
nothing kept it so, which is how a "machine-checked" claim became true of one run
and of nothing durable at 0.3.0.

All seven checks mutation-verified, each killed by exactly its own named test.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-07-21 13:43:09 -04:00
..
epiphany-bundle Text Projection 0.3.0: every production expanded, and one rule for values 2026-07-09 21:55:49 -04:00
epiphany-core Text Projection: every graph id projects, because graph_id! says so 2026-07-21 13:41:40 -04:00
epiphany-determinism P12-I2: wire the ratified MUSCLOID layout-object id derivation 2026-06-27 12:46:19 -04:00
epiphany-editor-core TransposeInterval becomes undoable; the frozen Transpose stays un-undoable 2026-07-09 16:45:57 -04:00
epiphany-editor-gui TransposeInterval: the faithful transpose, and the frozen one it replaces 2026-07-09 15:46:43 -04:00
epiphany-engrave P13-I2: Staff::default_clef is the fallback, not decoration 2026-07-09 14:47:42 -04:00
epiphany-layout-ir One tag vocabulary the compiler owns, and ratify the corpus in the companion 2026-07-09 20:32:35 -04:00
epiphany-ops Text Projection: the operation layer, and the tests that can see it fail 2026-07-21 13:43:09 -04:00
epiphany-render-svg P13-I3: delete the hand-written notehead anchors; teach the extractor 2026-07-09 14:53:47 -04:00
epiphany-testkit Text Projection 0.6.0: the operation vocabulary is grammar-directed 2026-07-21 13:42:21 -04:00