Three root causes: (1) a '%' begins a directive only in directive position (before document content, outside flow); everywhere else it is plain content, fixing misfires inside plain scalars, flow mappings, and block scalars. (2) %YAML accepts any 1.x (a higher minor is treated as 1.2 without error), rejects major != 1 and duplicate %YAML, and requires a following '---'; reserved and %TAG directives are accepted and ignored. A directive not followed by a document start is rejected with the new directiveWithoutDocument error. (3) An explicit '...' end marker closes the current document so following content begins a fresh document in parseStream; single-document parse still rejects multi-document input at compose time.
Tests/UnsupportedYAMLGapsFixtures.swift, StreamParsingTests, ScannerTests, and ParsingErrorTests were updated in lockstep to assert the now-correct behavior (percent-after-content is plain text; '...' then content is two documents; %YAML 1.3 is valid while 2.0 and duplicate %YAML are rejected); no test was weakened and multi-document rejection for single-document parse is still covered.
Flips 15 official YAML test suite cases (295/402); SF5V, 9MMA, B63P, H7TQ now correctly rejected. 6LVF and W4TN are reclassified to json-mismatch (blocked by other scalar gaps). Updates the manifest, fixtures, counts, and roadmap.
A mapping key is a full node: it may carry &anchor and !tag properties and may itself be an *alias. Fixes: (1) anchor/alias name scanning now stops at the first non-name character per yaml_parser_scan_anchor, so *a: reads as alias 'a' plus a mapping indicator instead of name 'a:'; (2) the block-mapping parser enters on a leading node property or alias, attaches same-line key properties to the key node, and emits alias keys directly; (3) an anchor or tag at value position with no same-line node composes an empty (null) value carrying the property, so 'a: &anchor' registers the anchor; (4) the composer registers an anchor's resolved model value (an empty anchored scalar registers null); (5) implicit keys with trailing spaces before the colon are recognized.
Flips 10 official YAML test suite cases to passing (280/402), including G9HC now correctly rejected. 2SXE no longer false-rejects but still value-mismatches on compact-mapping interpretation (a separate gap), so it is reclassified in the manifest rather than removed. Updates the manifest, fixtures, counts, and roadmap.
Compose an empty scalar wherever a node is grammatically required but the next token is a structural indicator or line/stream end, mirroring libyaml's process_empty_scalar: after a tag or anchor property with no node, as an absent mapping value (block and flow), as an absent mapping key (both the plain ': v' form and the explicit '?' form), in flow empty key/value forms ({ : }, { , : v }), and for an indented block node following properties. Also fixes a pre-existing block-sequence bug that nested a sibling '-' as a child when only properties remained on the entry line.
Empty scalars resolve through the existing resolver against the empty string, so !!str yields the empty string, bare empty or !!null yields null, and an empty key yields the empty string.
Flips 20 official YAML test suite cases to passing (270/402). CT4Q no longer false-rejects but still value-mismatches on flow plain-scalar folding (a separate gap), so it is reclassified in the manifest rather than removed. Updates the gap manifest, fixtures, counts, and roadmap.
Single (') and double (") quoted multi-line scalars now apply YAML 1.2 flow folding (sections 6.5, 7.3.1, 7.3.2): trailing whitespace before a break is stripped, leading whitespace on continuation lines is stripped, a single break between non-empty lines folds to one space, and N consecutive breaks yield N-1 literal line feeds (first and last lines keep their own leading/trailing spaces as content). A double-quoted backslash at end of line suppresses the break entirely.
Complete the double-quoted escape set: add \xXX and \UXXXXXXXX hex escapes plus the previously missing \0 \a \v \e, literal backslash-space, and named breaks \N \_ \L \P (existing \uXXXX surrogate-pair handling kept). The folding state machine mirrors scanner.c yaml_parser_scan_flow_scalar; implemented in Sources/Parsing/Scalar.swift.
Flips 30 official YAML test suite cases to passing (250/402). Updates the gap manifest, fixtures, count assertions, and roadmap.
Rewrite literal (|) and folded (>) block scalar content to YAML 1.2 section 8.1: preserve interior blank lines, apply 8.1.3 line folding (a single break between equally indented non-empty lines folds to a space, while blank lines and more-indented lines keep their breaks), preserve tabs in content (only block-indentation columns are stripped), and support the + keep chomping indicator alongside clip and strip.
The block scalar is now scanned as a single unit (header line plus all content lines) with indentation auto-detection in Scanner.BlockScalar.swift, mirroring the reference scanner, instead of being reassembled from a lossy per-line token array.
Flips 24 official YAML test suite cases to passing (220/402). Updates the gap manifest, vendored fixtures, count assertions, and the conformance roadmap.
Add structured validation diagnostics, JSON and Yams comparison gates, and lazy token/event parsing so production behavior is measured without retaining full intermediate parser arrays.
Add internal parsing events with marks, scalar styles, collection styles, alias events, and anchor/tag metadata. Add golden parser event tests for current block parser behavior.
Closes#2
