Smalltalk for Visual Studio Code

A complete, offline IDE experience for GNU Smalltalk — IntelliSense, refactoring, diagnostics, and navigation, with no image and no gst required.

Rich language support for Smalltalk (.st / .gst) with a file-based workflow. All language intelligence runs locally against a bundled TypeScript language server — fully offline, zero network I/O, and no telemetry — so it works the moment you install it, with or without GNU Smalltalk on your machine. Also on Open VSX for VSCodium, Gitpod, and Eclipse Theia.

Features

Everything here works offline with no gst installed — only Run Current File uses gst.


Syntax & semantic highlighting Role-accurate colors — instance vs. class variables, temporaries, parameters, selectors, and real classes.	Outline & navigation Outline, breadcrumbs, folding, workspace symbol search, and go-to-definition.
IntelliSense Completion over the GNU Smalltalk kernel + your workspace; keyword sends insert as snippets.	Diagnostics Syntax errors flagged as you type, with quick fixes to insert a missing closer or close a string.
Run Current File Execute the active `.st` / `.gst` with GNU Smalltalk in the integrated terminal.

Language intelligence — no `gst` required

IntelliSense / completion — kernel classes & selectors + workspace symbols; multi-part keyword selectors insert as snippets (at:put:). Kernel source is your installed GNU Smalltalk when found, otherwise a bundled reference (GNU Smalltalk 3.2.5).
Hover — selector signatures & implementors, class superclass chains, variable kinds, and numeric-literal decoding (16rFF → 255).
Diagnostics — live syntax squiggles badged smalltalk(parse), with insert-closer / close-string quick fixes.
Semantic highlighting — a capitalized name is colored as a class only when it resolves in your workspace or the kernel — otherwise a global.
References · Senders · Implementors · Call Hierarchy — the System Browser's cross-reference muscle memory, framed as an honest union of your workspace and the kernel, each result tagged with its source (dynamic dispatch can't be resolved statically — likely responders rank first, none are hidden).
Signature help — keyword messages show the matching selector(s) with the active parameter tracked.
Formatting — conservative and idempotent: document / selection / on-type. It only rewrites whitespace, so comments and code are never changed; formatting twice changes nothing. A file with a syntax error is left untouched.
Rename (refactor) — safe, scope-aware Rename Symbol (F2) for temporaries, arguments, instance variables, and classes, workspace-wide, with a Refactor Preview for multi-file changes. Selectors and kernel classes are refused with a reason rather than guessed.

Editing

Syntax highlighting for both brace- and chunk-format (!) files.
Snippets — idiomatic block-bearing templates (whileTrue:, on:do:, ifNil:ifNotNil:, inject:into:, detect:ifNone:, …).
Bracket matching & autoclosing, comment toggling (Ctrl/Cmd+/), auto-indent, and folding.

Requirements

GNU Smalltalk (gst) is optional. Every editing and language-intelligence feature above works without it. You only need gst for the Run Current File command, which executes your code.

Install GNU Smalltalk from the official site and ensure gst is on your PATH (or set smalltalk.gnuSmalltalkPath).
Verify with gst --version.

Quick start

Install — search leocamello.vscode-smalltalk in the Extensions view (Ctrl/Cmd+Shift+X), or get it from the Marketplace / Open VSX.
Open a .st file — highlighting, completion, outline, and diagnostics activate immediately (no gst needed).
Run it (optional) — with gst installed, run Smalltalk: Run Current File from the Command Palette or the editor right-click menu:
```
Transcript showCr: 'Hello, Smalltalk!'.
```

Settings

Setting	Default	Description
`smalltalk.gnuSmalltalkPath`	`""`	Absolute path to the `gst` executable. If empty, `gst` is looked up on your `PATH`.
`smalltalk.completion.kernelLibrary`	`auto`	Kernel-completion source: `auto` (installed kernel, else bundled), `bundled` (GNU Smalltalk 3.2.5 reference), or `off` (workspace symbols only). Active source is shown in the status bar.
`smalltalk.completion.kernelPath`	`""`	Optional path to a GNU Smalltalk kernel source directory (used when `kernelLibrary` is `auto`). Auto-discovered if empty.
`smalltalk.format.indentSize`	`4`	Spaces per indent level when formatting (tabs vs. spaces follow `editor.insertSpaces`).
`smalltalk.format.cascades`	`align`	Cascade layout — `align` (one segment per line) or `preserve`.
`smalltalk.format.keywordWrap`	`100`	Wrap a keyword message one-keyword-per-line past this column (`0` disables).
`smalltalk.format.blockStyle`	`preserve`	Block/method/class body layout — `preserve` your line breaks, or `expand` to one statement per line.
`smalltalk.trace.server`	`off`	Log the LSP client/server communication (`off` / `messages` / `verbose`).

Formatting is always available — it runs only on your format gestures (Format Document / Format Selection, or editor.formatOnSave) and is whitespace-only, so it never changes your code.

Commands

Available from the Command Palette (Ctrl/Cmd+Shift+P) and the editor right-click menu on a Smalltalk file:

Command	Description
Smalltalk: Run Current File	Save and run the active `.st` / `.gst` file with GNU Smalltalk in the integrated terminal.
Smalltalk: Senders of…	Find every send of the selector under the cursor (workspace ∪ kernel).
Smalltalk: Implementors of…	Find every implementor of the selector under the cursor (workspace ∪ kernel).

Privacy & Workspace Trust

No telemetry, fully offline. The extension performs no network I/O and collects no telemetry — your code never leaves your machine. This is enforced by a guard test in CI.
Workspace Trust. All language intelligence works in Restricted Mode. Because Run Current File executes code with gst, it is disabled until you trust the workspace, and a workspace-scoped smalltalk.gnuSmalltalkPath is ignored while untrusted.

Troubleshooting

gst not found — install GNU Smalltalk and ensure gst is on your PATH, or set smalltalk.gnuSmalltalkPath to its absolute path (e.g. /usr/local/bin/gst, or C:\Program Files\GnuSmalltalk\gst.exe). Only Run Current File needs it.
No highlighting — confirm the file has a .st / .gst extension and the language mode (bottom-right) is Smalltalk; reload the window if needed.
Semantic colors missing — set editor.semanticHighlighting.enabled to true (some themes default it off).

More help: the GitHub issues page.

Contributing

Contributions are welcome! This project follows a spec-driven process — see the Contribution Guide and the Roadmap. Bug reports and feature requests are best filed with the issue templates.

Feedback

File issues and ideas on the GitHub issues page. If the extension helps you, a Marketplace rating is much appreciated.

License

MIT.

Smalltalk

Leonardo Nascimento