Crate lattice_syntax 

Tree-sitter-backed syntax highlighting for lattice (DESIGN.md §5.3).

Status

• Languages bundled: Rust, Python, JavaScript, Markdown (block + inline split), plus a Plain no-op fallback.
• Incremental reparse landed (Option B, slices B.1–B.5). Syntax::parse_at_with_edits accepts EditDeltas, applies tree.edit() to the cached tree, and runs Parser::parse(_, Some(&old_tree)) so unchanged subtrees are reused. SyntaxHandle runs the parse on a spawn_blocking worker; request_reparse takes Buffer (O(1) Arc bump) so the input thread doesn’t allocate the source. App-side cache on App.visible_highlights_key short-circuits the per-frame highlight_lines walk when nothing changed.
• Flicker-free updates landed (C-series, slices C.1–C.5). The C-series turns the algorithmically-correct B-series into a user-visibly-flicker-free experience. The two-stage parse exposes Syntax::try_apply_intermediate (fast: tree.edit + source/version update, no parse) and reparse_with_cached_tree (slow: Parser::parse with cached tree as seed) so the SyntaxHandle worker can publish a byte-aligned intermediate snapshot before the parse completes. App synchronously line-shifts and byte-shifts its visible_highlights cache on every edit so held spans stay aligned with current content; the renderer never sees an empty/wrong intermediate. Grammar- driven edits (operators) flow through the same chokepoint so the C.x logic applies uniformly.
• Plugin extension API used by builtins, not yet by plugins.

Adding a new language:

1. Add the tree-sitter-<lang> crate as a dep.
2. Register it in registry::LangRegistry::standard.
3. Add a variant to Lang (and update Lang::detect_from_path for the canonical extension).

Injections

The shared registry::LangRegistry holds every registered grammar’s HighlightConfiguration; the per-document Syntax borrows refs through it. The injection callback looks up sibling configs by name – so a markdown \``rust … ```` block recurses into the rust config, and a markdown paragraph injects the inline-markdown parser. New languages drop in to the registry and become injection targets without further wiring.

Capture-name -> Style mapping lives in style.rs. The mapping is the v1 stand-in for the themable name-to-color tables described in §5.6 style mappings.

Re-exports

pub use crate::handle::SyntaxHandle;

pub use crate::indent::BracketSyntax;

pub use crate::indent::electric_columns;

pub use crate::indent::indent_columns_for_new_line;

pub use crate::indent::indent_for_new_line;

pub use crate::indent::is_electric_trigger;

pub use crate::indent::tree_levels_for_line;

pub use crate::indent::tree_levels_for_new_line;

pub use crate::lang::Lang;

pub use crate::modes::JavascriptMode;

pub use crate::modes::MarkdownMode;

pub use crate::modes::PythonMode;

pub use crate::modes::RustMode;

pub use crate::modes::TREE_SITTER_COMPLETION_SOURCE_ID;

pub use crate::modes::TreeSitterCompletionMode;

pub use crate::modes::TreeSitterSymbolSource;

pub use crate::modes::lang_for_mode_id;

pub use crate::modes::major_mode_id_for_lang;

pub use crate::modes::register_language_modes;

pub use crate::motions::SyntaxMotionIds;

pub use crate::motions::register_syntax_motions;

pub use crate::oneshot::oneshot_highlight_lines;

pub use crate::plugin_lang::LanguageName;

pub use crate::plugin_lang::LanguageRegistration;

pub use crate::plugin_lang::LanguageRegistrationError;

pub use crate::plugin_lang::PluginLanguages;

pub use crate::plugin_lang::PluginLanguagesHandle;

pub use crate::registry::GrammarSpec;

pub use crate::registry::LangRegistry;

pub use crate::syntax::Syntax;

pub use crate::syntax::SyntaxError;

pub use crate::syntax::SyntaxSnapshot;

pub use crate::text_objects::SyntaxTextObjectIds;

pub use crate::text_objects::register_syntax_text_objects;

pub use crate::theme_style::resolve_syntax_style;

pub use crate::theme_style::syntax_element_id;

Modules

conceal

Conceal rules — the per-language declaration of what to hide.

handle

SyntaxHandle – the async wrapper around per-document Syntax that runs reparses off the UI thread.

indent

Where should this line start?

lang

Languages this crate knows how to parse.

modes

Per-language major modes.

motions

Tree-sitter structural motions — ]f/[f/]F/[F (function), ]c/[c/]C/[C (class), ]a/[a/]A/[A (parameter), ]l/[l/]L/[L (loop). The motion counterpart to the structural text objects (text_objects.rs); both read the same textobjects.scm captures. See docs/dev/architecture/treesitter-motions.md.

oneshot

D.3.b.2 (2026-05-29): one-shot synchronous highlight.

plugin_lang

Languages registered at runtime rather than compiled in.

registry

Process-wide registry of HighlightConfigurations, keyed by language name. Owned via Arc so every Syntax instance holds a cheap clone and the injection callback in Highlighter::highlight can look up sibling configs (markdown block → markdown_inline; markdown’s fenced code blocks → rust / python / javascript / etc.) without each Syntax carrying its own copy.

style

Style category emitted by the highlighter, plus the capture-name table.

syntax

Syntax: per-document tree-sitter state.

text_objects

N.1.4c: structural (tree-sitter) text objects – the universal af/if (function), ac/ic (class), aa/ia (parameter), al/il (loop) grammar objects. They are first-class citizens of Lattice’s vim grammar (compose with every operator: daf, vic, yaa, and the zn narrow operator’s znaf), owned here in lattice-syntax per the locked N.1 design.

theme_style

Syntax → theme-element style bridge.

wasm_grammar

Loading grammars from WebAssembly, and the stores parsers need to run them.

Structs

StyledSpan

Byte-range span within one source line, carrying a semantic Style.

Enums

Style

Semantic style category emitted by the tree-sitter highlighter.