wit-mode

wit-mode: the major mode for WIT files (`.wit`) — tree-sitter highlighting and folds for the WebAssembly Interface Type language.

The major mode for WIT — WebAssembly Interface Types, the language plugin APIs are declared in. Activates automatically on .wit.

It is here for a reason more direct than most bundled languages: WIT is lattice's plugin API. Every seam a plugin implements is declared in a .wit file, so anyone writing a plugin reads and edits these, and until this mode existed they opened as plain text.

What it gives you

• Syntax highlighting — declarations (world, interface, record, enum, variant, flags, resource, type) and their names, function names, parameter names, types, @-attributes and package versions. /// doc comments style exactly as they do in Rust — lattice's syntax vocabulary has one comment style, so a doc comment is a comment.
• Folds — every braced item. A wit/ file is often one long interface, so folding is how you see its shape at all. za toggles, zR / zM open and close everything.
• Comment operators — gcc and gc{motion} use //, gC uses /* */.

What it does not give you

• No formatter. :format does nothing here. There is no consensus stdin-oriented WIT formatter — wasm-tools component wit rewrites a file in place, which is a different shape from the pipe every other language uses.
• No attribute highlighting. @since(...) and friends style through their constituent tokens rather than as a unit: in this grammar an attribute node spans the doc comment attached to its item, so capturing it whole paints the /// line as an attribute.
• No symbol list or text objects yet. :symbols will not find WIT items. Both want query files this mode does not ship; they are additive when a real need appears.

Notes

The highlighting query is lattice's own rather than the grammar crate's. The upstream query names its captures in the TextMate vocabulary (entity.name.type.interface), which lattice's theme resolver does not read — against it, a .wit file renders entirely unstyled.