Fix parsing of valid tag names that collide with move/NAG tokens#65
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The PGN tokenizer (TokenStream.consumeToken) is context-free and tries the
move-number / move / NAG matchers before HEADER_ID. Immediately after a
BEGIN_HEADER ('['), the only valid token is the tag name, but a name matching
the NAG regex (e.g. N, RR) or the move regex (e.g. Nf3, e4) was tokenized as a
NAG/move first, so the header parser rejected it with "Missing or invalid PGN
game header ID". This made spec-valid tag pairs such as [New "..."] impossible
to parse.
Make the tokenizer header-context-aware: when the previously emitted token is
BEGIN_HEADER, match HEADER_ID first (and only), falling back to the existing
MISSING_PGN_HEADER_ID error at the same position when no tag name is present
(preserving the diagnostic for malformed input like ["Somewhere"]). _matchHeaderId
already matches exactly the spec-permitted tag-name characters, so only the
dispatch order changes.
Adds a resource-driven regression fixture (tag-name-token-collision) covering
New, bare N, RR, Nf3, e4, and New alongside a recognized Annotator tag.
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Closes #64
Summary
Fixes parsing of spec-valid PGN tag pairs whose tag name looks like a SAN move or a NAG token (e.g.
[New "..."],[N "..."],[RR "..."],[Nf3 "..."],[e4 "..."]), which previously threwMissing or invalid PGN game header ID.Root cause
TokenStream.consumeToken()is context-free and tries the move-number / move / NAG matchers beforeHEADER_ID.Right after a
BEGIN_HEADER([) the only valid token is the tag name, but a name matching the NAG regex (N,RR) or the move regex (Nf3,e4) was tokenized as a NAG/move first, so the header parser failed.Fix
Make the tokenizer header-context-aware: when the previously emitted token is
BEGIN_HEADER, matchHEADER_IDfirst (and only).If no tag name is present, throw the existing
MISSING_PGN_HEADER_IDerror at the same position, preserving the diagnostic for malformed input like["Somewhere"]._matchHeaderId(/(\w+)/) already matches exactly the spec-permitted tag-name characters (letters/digits/underscore, section 8.1), so no regex change is needed — only the dispatch order.Tests
Adds a resource-driven regression fixture
tag-name-token-collision(6 games coveringNew, bareN,RR,Nf3,e4, andNewalongside a recognizedAnnotator).13 content-tests fail without the fix; the whole suite (5616 tests) passes with it, and
npm test(lint + unit) is green.