editor-syntaxes

name	editor-syntaxes
description	How to maintain editor syntax definitions for Dang. Use when adding or removing keywords, tokens, or language constructs.

Editor Syntax Maintenance

Dang has syntax definitions for three editors. When the language grammar changes (keywords added/removed, tokens renamed, new constructs), all three must be updated in sync.

Locations

VSCode

• editors/vscode/syntaxes/dang.tmLanguage.json — TextMate grammar
• Lives in the main repo (not a submodule)
• Keywords are in the keyword-control pattern as a \b(...)\b regex

Zed

• editors/zed/languages/dang/highlights.scm — tree-sitter highlights
• Submodule pointing to https://github.com/vito/zed-dang
• Commit inside the submodule first, then update the submodule pointer in the parent repo

Neovim

• editors/nvim/queries/dang/highlights.scm — tree-sitter highlights
• Submodule pointing to https://github.com/vito/dang.nvim
• Commit inside the submodule first, then update the submodule pointer in the parent repo

Tree-sitter highlights (Zed + Neovim)

The two .scm files are nearly identical but use different capture names (Zed uses @keyword.control, @variable.special, etc.; Neovim uses @keyword, @variable.builtin, etc.). Edit both when making changes.

Keywords are listed as (foo_token) nodes inside [ ... ] @keyword blocks. To add or remove a keyword, add or remove the corresponding (foo_token) line in both files.

TextMate grammar (VSCode)

Keywords live in the keyword-control repository entry as a single regex. To add or remove a keyword, edit the \b(...)\b alternation.

Committing

Since Zed and Neovim are submodules:

# 1. Commit in each submodule
cd editors/zed && git add -A && git commit -m "..." && cd ../..
cd editors/nvim && git add -A && git commit -m "..." && cd ../..

# 2. Commit submodule pointers + VSCode changes in parent
git add editors/zed editors/nvim editors/vscode/syntaxes/dang.tmLanguage.json
git commit -m "chore(editors): ..."

Embedded highlight query (REPL)

The REPL highlights its input with the same Zed highlights.scm, embedded into the binary at pkg/dang/highlights.scm (a generated copy, since go:embed can't follow the treesitter/queries/highlights.scm symlink into the submodule). ./hack/generate (via go generate ./...) refreshes it with cp, so it tracks the query automatically — just re-run generation after editing the Zed query. New capture names also need a case in captureClass in pkg/dang/highlight_common.go (kept in lockstep with docs/go/highlight.go).

Stale-parser gotcha (cgo build cache)

pkg/dang/danglang binds the generated parser by #include-ing treesitter/src/parser.c across package directories, and Go's build cache does not track that file. After ./hack/generate regenerates the grammar, cached builds keep linking the old parser; the first symptom is the embedded highlight query failing to compile ("Invalid node type <new_token>") and the REPL silently rendering plain text (TestHighlightCodeStylesAndPreservesText fails). Force one rebuild:

go test -a ./pkg/dang/ -run TestHighlight

(-a recomputes the cache entry; subsequent normal builds are fine.)

Checklist

When a language keyword or token changes:

1. Update editors/zed/languages/dang/highlights.scm
2. Update editors/nvim/queries/dang/highlights.scm
3. Update editors/vscode/syntaxes/dang.tmLanguage.json
4. Re-run ./hack/generate to refresh the embedded pkg/dang/highlights.scm
5. Force-rebuild the cgo parser binding (see gotcha above)
6. Add/refresh treesitter/test/corpus/ and editors/highlights/corpus/ cases for the new construct (tree-sitter test --update, go test ./editors/ -run TestNeovimHighlights -update)
7. Commit submodules, then parent repo