Teach the syntax engine that one buffer can hold more than one
language. After the root parse, run the grammar's injections.scm, parse
each embedded region with the injected language, and merge every
layer's highlight spans. First consumer: markdown fenced code + inline
(zero new grammars — the block grammar already ships an injection query
and the injected langs already have grammars from #118).
Engine (src/syntax.rs):
- ParseTreeBundle now holds Vec<Layer> (root layer 0 + injected
children, depth-ascending); installed atomically so the existing
Arc::ptr_eq style gate and highlight cache keep working (Q#IJ1).
- run_parse builds layers on the worker: run injections.scm, resolve
the injected language, compute Vec<Range> (exclude NAMED children,
intersect the parent's ranges), set_included_ranges cold-parse,
recurse — bounded by depth (3), a layer backstop (4096), and a
(lang,ranges) visited guard; any child failure drops that child only
(Q#IJ3/IJ5). LanguageEntry gains injections_query; markdown_inline is
registered (retires the M9.7 block-only floor); markdown/rust carry
injection queries.
- Injected languages resolve off the static BUILTIN_LANGUAGES table
(Send loaders + query sources), preserving lazy loading. Dynamic
fence names go through a case-folded alias map seeded with defaults
and Lua-extensible via pmacs.parse.injection_aliases, snapshotted into
ParseRequest at dispatch so the worker never touches the Rc registry
or a Lua table (Q#IJ2/IJ4). Highlight queries are resolved at settle
(resolve_layer_queries), keeping query compilation main-thread/cached.
Producers:
- SyntaxHighlightView (grid) iterates layers shallow-to-deep so a
deeper layer's styling wins within its region (Q#IJ6/IJ7).
- scoped_style_spans (wire) flattens all layers into DISJOINT effective
spans via a boundary sweep, since the GPU re-sorts spans by start
(replace_style_spans / merge_style_spans) and would otherwise destroy
producer order. The GPU source_color_at consumer is fixed to fold all
covering spans (matching semantic_client's effective_style_at) rather
than returning the first.
Named-children exclusion: content ranges exclude only NAMED children
(matching tree-sitter-md's own inline splitter) — excluding a block
inline node's anonymous text tokens would shred the paragraph into
unparseable fragments.
13 acceptance gates (framing docs/multi-language-injections-framing.md):
layer structure, absolute child offsets, alias resolution (static +
case-folded dynamic + unknown-skip + Lua-async override), multi-range
inline, recursion bounds, wire + grid + GPU producers, incremental edit
/ new fence, many-paragraph settle budget with tail coverage, and the
single-layer regression guard.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01YJ9FQ832QwftJXCD9LeFan
Levi Neuwirth
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