VJ Language for Visual Studio Code

Rich language support for VJ - a modern systems programming language with Ruby-like syntax.

✨ Features

🎨 Syntax Highlighting

• Full syntax support for VJ source files (.vj)
• Markdown code blocks: Syntax highlighting in Markdown files for ```vj code blocks
• Semantic highlighting for keywords, types, functions, and more

💡 IntelliSense

• Code Completion: Smart suggestions as you type
• Hover Information: See type info and documentation
• Signature Help: Parameter hints for functions

🔍 Code Navigation

• Jump to definition (F12)
• Find all references (Shift+F12)
• Symbol search across workspace (Ctrl+T / Cmd+T)

🐛 Real-time Diagnostics

• Undefined variable detection
• Type checking
• Unused variable warnings
• Division safety analysis

🎯 Code Formatting

Integrated vjfmt formatter - use Cmd+Shift+F (Mac) or Ctrl+Shift+F (Windows/Linux)

🔧 Built-in Functions

VJ provides global built-in functions for I/O operations (no import required):

• I/O Functions: print(), println(), eprint(), eprintln(), flush(), clear(), readln()
• Utility Functions: len(), typeof(), assert()

All I/O functions have IntelliSense support with signature help and documentation.

📝 Quick Examples

Basic Program

func main() {
    let name = "World"
    println("Hello, " + name + "!")
}

Structs and Methods

struct Point {
    x: float;
    y: float;
}

impl Point {
    func distance(other: Point) -> float {
        let dx = this.x - other.x
        let dy = this.y - other.y
        return sqrt(dx * dx + dy * dy)
    }
}

Pattern Matching

enum Status {
    Active,
    Paused,
    Stopped
}

match status {
    Status::Active => println("Running"),
    Status::Paused => println("Paused"),
    Status::Stopped => println("Done"),
}

Interfaces

interface Drawable {
    func draw() -> void;
}

struct Circle {
    radius: float;
}

impl Drawable for Circle {
    func draw() {
        println("Drawing circle")
    }
}

Generics with Constraints

interface Comparable {
    func compare(other: Self) -> int;
}

func max<T: Comparable>(a: T, b: T) -> T {
    return a.compare(b) > 0 ? a : b
}

🚀 Getting Started

Installation

Install from VS Code Marketplace: Search for "VJ Language" in Extensions (Ctrl+Shift+X / Cmd+Shift+X)

Quick Setup

1. Install the extension
2. Open or create a .vj file
3. Start coding with IntelliSense support!

Optional: vjfmt Formatter

# If you have the VJ toolchain installed
which vjfmt  # Should show path to formatter

Configure formatter path if needed:

{
  "vj.format.vjfmtPath": "vjfmt"
}

📚 Language Features

let x = 10
const PI = 3.14159
let mut counter = 0

counter = counter + 1

// Both 'func' and 'fn' keywords work
func add(a: int, b: int) -> int {
    return a + b
}

fn multiply(x: int, y: int) -> int {
    return x * y
}

// Public function
pub fn greet(name: string) {
    println("Hello, " + name)
}

enum Option {
    Some(int),
    None
}

enum Result {
    Ok { value: int },
    Err { message: string }
}

match result {
    Result::Ok { value } => println("Success: " + str(value)),
    Result::Err { message } => println("Error: " + message),
}

// If-elif-else
if x > 0 {
    println("positive")
} elif x < 0 {
    println("negative")
} else {
    println("zero")
}

// Loops
for i in 0..10 {
    println(str(i))
}

while running {
    process()
}

// Defer for cleanup
defer cleanup()

// Import entire module
import std.math

// Selective imports
import std.math.{ PI, sqrt }

// Module declaration
mod utils {
    pub func helper() { }
}

⚙️ Configuration

Useful Settings

{
  // Number of problems to show
  "vj.maxNumberOfProblems": 100,
  
  // Path to vjfmt formatter
  "vj.format.vjfmtPath": "vjfmt",
  
  // Debug language server communication
  "vj.trace.server": "off"
}

Commands

cd vscode-vj
npm install
cd server && npm install && cd ..
npm run compile

npm run package  # Creates .vsix file

🐛 Troubleshooting

Extension not working?

• Make sure you're editing a .vj file
• Check Output panel: View → Output → "VJ Language Server"
• Try: Command Palette → "VJ: Restart VJ Language Server"

Performance issues?

• Reduce max problems: "vj.maxNumberOfProblems": 50

📄 License

MIT License - see LICENSE