The JSON writer escapes the characters a YAML reader mangles. PureYAML.JSON.parse and parseLocated read JSON with those characters held back and given back, so no position moves, and Convert.convert takes the format of its source.
The validation module already implemented the composable-rule idiom under
its own names (Check/Issue/SubjectContext) and a value-type Validator with
duplicated traversal machinery per layer. Renamed the core types to the
canonical names (Validation/ValidationError/ValidationErrorCollection/
ValidationContext/BuiltinValidation/AnyValidation), converted Validator to
a reference-type class with the two-tier default-rule split, and genericized
it over both Subject and Document via a new Traversable protocol so the
model and tagged layers share one walk engine instead of two copies. Wired
the JSON-representability rule set into the same shape and closed the two
missing pieces (unwrap combinator, JSON coverage/config-pin tests).
The ported engine wins every conflict: main's post-fork patches to the
hand-rolled Scanner and TokenEventParser land on deleted files and are
dropped; their behaviors are carried by the port and guarded by the
whole-suite conformance gate (402/402 passing).
Merge adaptations, all gates green (style, namespacing, forbidden
patterns, changelog, roadmap, swiftformat, swiftlint strict, build,
full test suite, whole-suite conformance sweep):
- PureYAMLJSON representability rules move onto the Check algebra,
replacing the retired legacy Rule type.
- The permissive tag-handle pre-pass is removed; the port rejects an
undefined handle at parse time (suite case QLJ7) and the validation
report carries it as a parse diagnostic.
- EventStreamComposer's nested types split one-per-file per the
namespacing gate.
- Tests pinned to old-engine behavior were re-verified against the
reference and updated: libyaml rejects an explicit-key continuation
ending at a value colon, and suite case QB6E requires rejecting a
quoted continuation at column 0.
- CHANGELOG unreleased entries from both lines are preserved in two
groups with a provenance note.
Closes#1, closes#3
PureYAMLJSON is a separate library product layered on the core engine. JSON is
a subset of YAML 1.2, so the existing parser already reads both into one value
tree; this product adds the missing half and the value-level policy:
- JSON.Writer: a pure-Swift RFC-8259 serializer (no Foundation; WASI-clean),
pretty or compact, rejecting non-string keys and non-finite numbers.
- JSON representability rules expressed in PureYAML's own Validation framework:
mappingKeysAreStrings and numbersAreFinite join the core mappingKeysAreUnique.
- JSON.Validator: the representability rule set plus issues(for:)/isRepresentable.
- JSON.Convert: standalone convert(_:to:) with the round-trip law (parse ->
validate representability -> emit -> re-parse must equal the source). To JSON
rejects complex keys and non-finite numbers; to YAML rejects duplicate keys,
which are legal in JSON but not in YAML.
19 tests cover the writer, the rules, and both conversion directions including
the dual-rejection edges. Carved out of the catch-all Sources/Tests paths via
exclude so the core PureYAML target is unchanged.
