VS Code Extension

This note covers the Visual Studio Code extension for Compact, which provides syntax highlighting, snippets, and integrated compilation.

Docs: VS Code Extension

Intuition First

The VS Code extension adds Compact language support to Visual Studio Code. It highlights keywords, provides code snippets, and integrates with the compiler for error reporting.

Installed via a VSIX file, not the VS Code marketplace. The extension is maintained by the Midnight team.

Installation

Download the VSIX

Download the latest release:

curl -LO https://raw.githubusercontent.com/midnight-ntwrk/releases/gh-pages/artifacts/vscode-extension/compact-0.2.13/compact-0.2.13.vsix

Install in VS Code

Open VS Code
Go to Extensions (Ctrl+Shift+X)
Click Install from VSIX…
Select the downloaded file

Features

Feature	What it does
Syntax highlighting	Keywords, types, circuits colored
Code snippets	Insert common patterns
Error highlighting	Inline compiler errors
Build integration	Compile from VS Code
File templates	New Compact files

Syntax Highlighting

The extension recognizes:

Keywords: circuit, witness, export, ledger, enum, struct, module, import, assert
Types: Uint<n>, Uint<0..n>, Field, Boolean, Bytes<n>, Map, Vector
Literals: strings, numbers, booleans
Comments: // and /* */

Code Snippets

Type the snippet prefix and press Tab:

Prefix	Inserts
`ledger`	State declaration
`constructor`	Constructor block
`circuit`	Circuit function
`witness`	Witness function
`stdlib`	Standard library import
`if`	If statement
`for`	For loop
`fold`	Fold expression
`enum`	Enum definition
`struct`	Struct definition
`module`	Module definition
`assert`	Assert statement
`compact`	Full contract template

Building from VS Code

Add a Build Script

In package.json:

{
  "scripts": {
    "compact": "compact compile --vscode ./contracts/myContract.compact ./contracts/managed/myContract"
  }
}

The --vscode flag formats errors for VS Code.

Compile

yarn compact

Errors appear in the Problems panel.

Task Configuration

For integrated building, create .vscode/tasks.json:

{
  "version": "2.0.0",
  "tasks": [
    {
      "label": "Compile Compact",
      "type": "shell",
      "command": "npx compact compile --vscode --skip-zk ${file} ${workspaceFolder}/contracts/managed",
      "group": "build",
      "problemMatcher": [
        "$compactException",
        "$compactInternal",
        "$compactCommandNotFound"
      ]
    }
  ]
}

Then press Ctrl+Shift+B to build.

Creating a New Contract

Open the command palette (Ctrl+Shift+P)
Type Snippets: Fill File with Snippet
Select Compact

This creates a full contract template:

pragma language_version 0.22;

import CompactStandardLibrary;

export ledger state: State;

enum State { UNSET, SET }

constructor() {
}

export circuit init(): [] {
}

export circuit interact(): [] {
}

Quick Recap

Install via VSIX file.
Syntax highlighting works automatically.
Use snippets for common patterns.
Add --vscode to compile command for error integration.
Use Ctrl+Shift+B to build.

Cross-Links

Previous: Neovim Setup Neovim editor
Next: Testing and Debugging Error handling
See also: Setting Up the Compiler Toolchain installation

Keyboard shortcuts

Compact Book