A ':' that opens a line with no key before it is a mapping entry with a
null key (': value', a bare ':', or a null-keyed entry among others). The
scanner emitted the ':' with no preceding key, so the parser rejected it
as a missing node.
The scanner now synthesizes the empty key and its node for such a ':'. To
avoid mistaking an explicit key's value indicator for a null key, it tracks
a pending block-level '?' key: a ':' opening a line is that key's value
when one is pending, and only a synthesized null key otherwise. The flag
is set and cleared only at flow depth zero, so a ':' inside a flow complex
key ('? {a: b}' then ': c') does not disturb the pending block key.
Measured against the official YAML test-suite, parse-level conformance
rises from 283/333 (85.0%) to 287/333 (86.2%) with no regression.
A block sequence entry cannot follow a flow collection that closed earlier
on the same line ('- { y: z }- invalid', '- [a] - b'): the entry would
begin a sequence inline after a complete node. The scanner accepted it,
producing extra sequence items.
The scanner now records when a flow collection closes at the top level on
the current line and rejects a following block entry. The flag resets at
each line break, so a flow collection on its own line is unaffected, and a
nested block entry ('- -') has no preceding flow close, so it stays valid.
Measured against the official YAML test-suite, parse-level conformance
rises from 276/333 (82.9%) to 277/333 (83.2%) with no regression.
In a flow collection a '-' that begins a plain scalar must be followed by
a non-indicator character. Immediately before a flow indicator ('[-]',
'[-, -]', '{a: -}') the dash is not a valid scalar, but the scanner
accepted it as the scalar '-'.
scanToken now rejects a '-' in flow context when the next character is a
flow indicator, before falling through to plain-scalar scanning. A dash
followed by ordinary content stays valid: negative numbers, a dash inside
a scalar, a dash starting a word, and a quoted dash are unaffected.
Measured against the official YAML test-suite, parse-level conformance
rises from 273/333 (82.0%) to 275/333 (82.6%) with no regression.
A block scalar's leading empty lines must not be more indented than its
first non-empty line, so a blank line wider than the content (a 5-space
blank above 2-space content, or 2,3-space blanks above 1-space content) is
malformed. The scanner buffered the leading blanks without comparing their
indentation to the content, folding such input into the value.
The scanner now records the widest leading blank and rejects the scalar
when it exceeds the content indentation, established for both auto-detected
and explicit indicators. Indentation is counted in leading spaces, not
tab-expanded width, so a tab on a blank line ('␣\t') is one space rather
than a jump to the next tab stop, keeping such valid block scalars intact.
Measured against the official YAML test-suite, parse-level conformance
rises from 270/333 (81.1%) to 273/333 (82.0%) with no regression.
A block sequence cannot be an implicit key's value on the same line as its
':' (key: - a); the value must begin on a following line, or use flow
style. The scanner accepted the inline block entry and parsed it as the
key's sequence value.
The block-entry case now rejects a '-' that starts a sequence when the
line already holds an implicit-key mapping value, reusing the same
same-line-pair flag as the inline nested mapping rule. As there, an
explicit- or null-key ':' opens its line and does not set the flag, so a
compact sequence value after it stays valid, as do a sequence on the next
line, a nested sequence, a flow sequence, and a negative number (key: -1).
Measured against the official YAML test-suite, parse-level conformance
rises from 260/333 (78.1%) to 261/333 (78.4%) with no regression.
Block style permits only one mapping pair per line, so a scalar followed
by ':' after a block-level value on the same line (a: b: c, a: 'b': c,
x: { y: z }in: valid, or trailing content after a quoted value) is not a
new key but a forbidden inline nested mapping. The scanner synthesized an
implicit key for any scalar followed by ':', regardless of position, so
these parsed as nested mappings instead of failing.
The scanner now records when a line already holds a block-level mapping
pair and suppresses a further implicit key on that line, in plain and
quoted scalars alike. The flag is set only for an implicit-key ':' (one
preceded by its key on the same line): a ':' that opens its line is an
explicit- or null-key value indicator, whose value may be a compact
mapping (? k then : a: 1), so that, flow mappings, next-line nesting, and
colons inside scalars stay valid.
Measured against the official YAML test-suite, parse-level conformance
rises from 256/333 (76.9%) to 260/333 (78.1%) with no regression.
The YAML grammar requires every directive to head an explicit document,
so a directive must be followed by a '---' marker. The scanner accepted a
directive with no document at all: '%YAML 1.2' alone, or '%YAML 1.2' then
a '...' document-end marker, parsed without error.
The scanner now records the line of a directive awaiting its document,
clears it at a document start, and rejects a still-pending directive at a
document-end marker and at stream end. Both scan drivers finalize through
the same stream-end path, so the check lives in one helper called from
each. The rule applies to any directive, including an unrecognized one
(which is otherwise still ignored); the directive test that relied on an
unrecognized directive parsing without a '---' is corrected to include
one, since that leniency is not permitted by the grammar.
Measured against the official YAML test-suite, parse-level conformance
rises from 253/333 (76.0%) to 255/333 (76.6%) with no regression.
The %YAML directive takes exactly one parameter, the version, and at most
one may appear per document. The scanner checked only that a valid version
was present: it ignored any further tokens, so '%YAML 1.2 foo' was
accepted, and it did not track that a %YAML directive had already been
seen, so a repeated directive was accepted too. It now rejects an extra
parameter (allowing only a trailing comment) and a second %YAML directive,
resetting the per-document flag at each document boundary. A well-formed
directive, with or without a trailing comment, is unaffected.
Measured against the official YAML test-suite, parse-level conformance
rises from 251/333 (75.4%) to 253/333 (76.0%) with no regression.
A '#' that begins a comment must be preceded by whitespace or open the
line; glued to earlier same-line content (e.g. "value"# c, [ a, b ]#c,
>#c, a flow entry then ,#c) it is neither a comment nor, in those
positions, plain-scalar content, so the document is malformed. Such input
was previously accepted as a comment.
A '#' that opens a line, follows a space, or sits inside a plain scalar
(a#b, where it stays literal content and never reaches this check) is
unaffected. The scanner tracks whether a real token has been scanned on
the current physical line, reset on each line break, rather than comparing
token line numbers: the streaming tokenizer drains its token buffer
between scans, and a block scalar's blank line emits an empty scalar
attributed to the next line, either of which would misread as content.
Measured against the official YAML test-suite, parse-level conformance
rises from 243/333 (73.0%) to 247/333 (74.2%): four wrongly-accepted
invalid documents are now rejected, with no valid document regressing.
The scalar-scanning routines move to Scanner.Scalars.swift to keep the
file within the length limit.
A quoted mapping key followed by a space and then ':' ('"key" : value')
failed to parse: the scanner synthesizes the implicit mapping-key token by
checking the character immediately after the key, but a quoted scalar
stops at its closing quote, leaving the separating space, whereas a plain
scalar consumes that space into itself and ends at the colon. The quoted
path now looks past spaces for the colon, which the spec allows between an
implicit key and its value indicator.
Quoted keys with no space, quoted values, and plain keys (which already
worked with a space) are unaffected. Measured against the official YAML
test-suite, parse-level conformance rises from 238/333 (71.5%) to
240/333 (72.1%), with no regression.
A multi-line plain scalar whose value sits one line below its mapping key
stopped after the first line: the continuation check compared the next
line's indent against the value's own indent, which had been pushed onto
the indentation stack, so a continuation at the same indent failed the
strict '>'. It now compares against the parent block's indent (the level
below the value's, when the scalar begins exactly at the indentation top),
matching the spec: a continuation must exceed the mapping's indentation,
not the value's own. Inline values are unaffected, since their top-of-
stack already is the parent block's indent.
Measured against the official YAML test-suite, parse-level conformance
rises from 211/333 (63.4%) to 221/333 (66.4%) with no regression across
the existing 306 tests. The +10 covers the multi-line plain scalar family
the harness flagged, not just the case investigated.
Blank lines between a block scalar header and its first content line come
before the indent token, so the earlier blank-line capture skipped them.
Buffer leading blanks while the block indentation is still pending and
flush them as empty content once the indent is established, in the shared
indentation path used by both scan loops. Also fix folded bodies to emit
a break for a leading blank rather than folding it into a leading space.
This closes the last block-scalar blank-line edge from #57.
The scanner dropped every blank line within and after a block scalar, so
a literal block lost internal blank lines, a folded block turned a blank
line into a space rather than a newline, and the keep indicator could not
preserve trailing blank lines. Capture blank lines as empty content in
both the batch scan loop and the streaming TokenCursor loop, which had
drifted as duplicate copies. Rework blockScalarValue to apply literal
versus folded line semantics and clip/strip/keep chomping over the
captured lines; content without blank lines is unchanged. Re-pin the
multiline-scalar test whose expectation encoded the old dropped-blank
behavior, and add a chomping-and-folding test matrix.
The scanner consumed the `+` indicator of a `|+` / `>+` block scalar but
mapped it to nothing, so keep was silently treated as clip, and a scanner
test baked that in. Add a `keep` case to BlockScalarChomping, recognize
`+` in the header scanner, and correct the test. Full keep value semantics
(preserving trailing blank lines) depend on scanner blank-line capture and
are tracked in #57; this commit fixes the token classification only.
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.
