Language support for MetaScript -- a systems programming language with TypeScript syntax, compile-time macros, match expressions, Rust-style error handling, and multiple backends (C, JavaScript, Erlang experimental).
Features
Syntax Highlighting
Rich TextMate grammar covering all MetaScript syntax:
- Keywords, control flow, declarations
- Match expressions with
=> arms and | alternatives
- Macro decorators (
@target, @comptime, @emit, @derive, etc.)
- Sized integers (
int8-int64, uint8-uint64, float32, float64)
- Ownership keywords (
move, borrow, defer, unreachable)
- JSX tags and attributes
- Template literals with
${expr} interpolation
.code compile-time character code access
Semantic Highlighting
When the language server is running, semantic tokens provide more accurate highlighting than the TextMate grammar alone, including:
- Correct differentiation of types, variables, parameters, and functions
- Mutable vs. immutable bindings
- Compile-time vs. runtime expressions
Language Server Features
Powered by the msc lsp language server:
- Diagnostics -- real-time error and warning reporting
- Completions -- context-aware suggestions with snippet support
- Hover -- type information and documentation on hover
- Go to Definition -- jump to symbol definitions
- Find References -- find all usages of a symbol
- Rename -- project-wide symbol renaming
- Inlay Hints -- inline type annotations and parameter names
- Code Actions -- quick fixes and refactoring suggestions
Code Snippets
30+ snippets for common MetaScript patterns:
| Prefix |
Description |
fn |
Function declaration |
efn |
Exported function declaration |
iface |
Interface (data struct) |
match |
Match expression |
rmatch |
Match expression with return |
enum |
Enum declaration |
forof |
For-of loop |
test |
Test case |
testgroup |
Test group |
imp |
Import statement |
result |
Result<T, E> type |
try |
Try expression with catch |
target |
@target conditional block |
defer |
Defer statement |
extern |
Extern FFI function |
class |
Class declaration |
type |
Type alias |
distinct |
Distinct type |
arrow |
Arrow function |
move |
Move ownership |
outp |
Out parameter |
Type any prefix and press Tab to expand.
Status Bar
The status bar shows the language server state:
- Spinning icon -- server is starting
- Check mark -- server is ready
- Error icon -- server has stopped or crashed
Click the status bar item to restart the language server.
Auto-Restart
If the language server crashes, the extension automatically restarts it with exponential backoff (up to 5 attempts). After 5 failures, it stops and prompts you to restart manually.
Installation
From VS Code Marketplace
Search for "MetaScript" in the Extensions view (Ctrl+Shift+X / Cmd+Shift+X) and click Install.
From VSIX
- Build the extension:
cd tools/editor-plugin/vscode
npm install
npm run package
- Install the
.vsix file:
code --install-extension metascript-0.2.0.vsix
Development
- Open this directory in VS Code
- Run
npm install
- Press
F5 to launch the Extension Development Host
Configuration
| Setting |
Type |
Default |
Description |
metascript.serverPath |
string |
"" |
Path to msc executable. Leave empty to auto-detect. |
metascript.trace.server |
string |
"off" |
LSP trace level: off, messages, or verbose. |
metascript.diagnostics.enable |
boolean |
true |
Enable diagnostics from the language server. |
metascript.inlayHints.enable |
boolean |
true |
Enable inlay hints (type annotations, parameter names). |
metascript.semanticHighlighting.enable |
boolean |
true |
Enable semantic token highlighting. |
metascript.completion.snippets |
boolean |
true |
Enable snippet completions from the server. |
Commands
| Command |
Description |
MetaScript: Restart Language Server |
Stop and restart the LSP server |
MetaScript: Expand Macro at Cursor |
Show the expanded form of a macro |
MetaScript: Show Output Channel |
Open the MetaScript output panel |
Requirements
- VS Code 1.85.0 or later
- MetaScript compiler (
msc) installed and available on PATH, or configured via metascript.serverPath
To install the MetaScript compiler:
git clone https://github.com/metascriptlang/metascript
cd metascript
zig build install
Server Discovery
The extension searches for msc in the following order:
metascript.serverPath setting (supports ~ expansion)- Workspace directory:
./zig-out/bin/msc, ./bin/msc, ./node_modules/.bin/msc
- Extension directory:
./bin/msc
- System PATH
Troubleshooting
Server not found: Set metascript.serverPath to the full path of your msc binary, or ensure it is on your system PATH.
Server crashes on startup: Open the MetaScript output channel (MetaScript: Show Output Channel) to see error details. Try running msc lsp directly in a terminal to check for issues.
No semantic highlighting: Verify that metascript.semanticHighlighting.enable is true and that the server is in the "Ready" state (check the status bar).
Stale diagnostics: Use MetaScript: Restart Language Server to force a fresh analysis.
Contributing
Contributions are welcome. Please file issues and pull requests at github.com/metascriptlang/metascript.
License
MIT
