gsx — VS Code Extension

VS Code language support for gsx — JSX-style HTML templating for Go.

What it is

gsx is a Go templating language that uses JSX-style syntax: components are capitalized tags, holes are { expr } blocks, and files embed Go, CSS, and JavaScript inline. This extension provides syntax highlighting and a full language client backed by gsx lsp.

Requirements

The extension requires the gsx binary for diagnostics, hover, go-to-definition, references, and formatting. Install it with:

go install github.com/gsxhq/gsx/cmd/gsx@latest

Alternatively, when you open a .gsx file without gsx on your PATH the extension shows a one-click "Install gsx" prompt that runs the command for you.

Features

• Syntax highlighting — tags, components, holes ({ expr }), embedded Go blocks, and embedded <style>/<script> with proper scope nesting
• Diagnostics — parse and type errors shown inline, powered by gsx lsp
• Hover — Go identifier documentation on hover
• Go-to-definition — navigate to symbol definitions across the workspace
• Find references — list all references to a symbol
• Formatting — format-on-save via gsx lsp / gsx fmt

Settings

Commands

How it works

When a .gsx file is opened the extension resolves the gsx binary (setting

PATH > GOBIN > GOPATH/bin) and launches gsx lsp as a stdio LSP server. All diagnostics, hover, go-to-definition, references, and formatting responses come from that process. Syntax highlighting works independently of the binary via the bundled TextMate grammar.

Testing the grammar

Two tiers, run together by npm test:

• Curated scope assertions (npm run test:grammar) — the test/grammar/*.gsx files pin exact scopes at specific positions (vscode-tmgrammar-test).
• Corpus balance gate (npm run test:corpus) — test/corpus-authoritative/ holds .gsx snippets vendored from the canonical gsx codegen corpus (gsx/internal/corpus/testdata/cases/**). The gate tokenizes each with the grammar and asserts the scope stack returns to root at EOF, catching runaway scopes (an unterminated string/comment/embedded block that bleeds across the file). It does not check per-token correctness — the curated tier does that.

Re-sync the corpus when the gsx corpus changes: npm run sync:corpus (gsx checkout at ../gsx or $GSX_REPO). This mirrors tree-sitter-gsx's authoritative-corpus gate.

Releasing

Releases are one-click via the Release GitHub Actions workflow (workflow_dispatch). It runs the full CI gate, bumps package.json, tags, pushes to main, cuts a GitHub release, and publishes to the VS Code Marketplace + Open VSX. Update CHANGELOG.md on main before triggering — the workflow does not touch it.

Trigger from the CLI (version is patch / minor / major, or an explicit version like 0.0.4):

gh workflow run release.yml -f version=patch
gh run watch "$(gh run list --workflow release.yml --limit 1 --json databaseId --jq '.[0].databaseId')"

Or from the GitHub UI: Actions → Release → Run workflow.

Links

• Documentation: gsxhq.github.io
• Source: github.com/gsxhq/gsx
• Extension source: github.com/gsxhq/vscode-gsx