MSV Language for VS Code

MSV is an interpreted programming language with support for object-oriented, functional, and procedural paradigms. It features a clean syntax with actions, classes, protocols, hooks, computed properties, pattern matching, and a built-in test system.

Installation

From VS Code Marketplace

Open VS Code
Go to Extensions (Ctrl+Shift+X)
Search for "MSV Language"
Click Install

From VSIX

Download the .vsix file from releases
Open VS Code
Go to Extensions (Ctrl+Shift+X)
Click ... → Install from VSIX...
Select the downloaded file

Manual Installation

Clone this repository
Copy the msv-vscode folder to ~/.vscode/extensions/
Restart VS Code

Features

Syntax Highlighting

Full TextMate grammar with semantic scopes for:

Keywords (control flow, declarations, operators)
Built-in types (int, float, bool, string, array, dict)
Strings with escape sequence support
Numbers (integer and float)
Comments (# single-line)
Function definitions and calls
Class, protocol, and computed property declarations

Snippets

Prefix	Description
`action`	Define a new action (function)
`actionr`	Define an action with return type
`class`	Define a new class
`class-adopt`	Define a class adopting a protocol
`protocol`	Define a new protocol
`when`	Conditional when/otherwise block
`when-only`	Conditional when without otherwise
`switch`	Switch/case block with multiple cases
`switch-min`	Minimal switch/case block
`try`	Try/catch error handling
`test`	Define a test block
`test-assert`	Test with assertion
`assert`	Assert a condition
`hook-before`	Hook that runs before an event
`hook-after`	Hook that runs after an event
`extend`	Extend an existing class
`computed`	Define a computed property
`wloop`	While loop
`floop`	For-each loop
`floop-range`	For loop with range
`map`	Map over a collection
`filter`	Filter a collection
`reduce`	Reduce a collection
`adopt`	Adopt a protocol
`action`	Define a new action

Language Configuration

Auto-closing brackets: {}, [], ()
Auto-closing quotes: "", ''
Bracket matching and surrounding pairs
Comment toggling with Ctrl+/ (# comments)
Smart indentation for blocks

Example Code

# Hello World
action greet(name) {
    paint "Hello, " + name + "!"
}

# Class with protocol
protocol Speakable {
    action speak()
}

class Dog adopt Speakable {
    action speak() {
        paint "Woof!"
    }
}

# Conditional
when x > 10 {
    paint "Large"
} otherwise {
    paint "Small"
}

# Switch
switch value {
    case 1 {
        paint "One"
    }
    default {
        paint "Other"
    }
}

# Loop
floop item in items {
    paint item
}

# Error handling
try {
    result = riskyOperation()
} catch error {
    paint "Error: " + error
}

# Test
test "addition works" {
    assert add(2, 3) == 5
}

# Functional
squared = numbers.map(action(x) { x * x })
evens = numbers.filter(action(x) { x % 2 == 0 })
sum = numbers.reduce(action(acc, x) { acc + x }, 0)

# Hook
hook before render {
    paint "Preparing..."
}

# Computed property
computed fullName {
    return firstName + " " + lastName
}

Snippets Documentation

All snippets are triggered by typing the prefix and pressing Tab or Enter. Placeholders ($1, $2, etc.) can be cycled through with Tab. See the table above for available snippets.

Requirements

VS Code 1.70.0 or higher

Extension Settings

This extension contributes the following settings:

msv.language: Language identifier (msv) registered for .msv files

Known Issues

No LSP support yet (syntax highlighting only)
No autocompletion or error checking
No debugger integration

Release Notes

0.1.0

Initial release:

Syntax highlighting for all MSV constructs
23 practical snippets
Language configuration with auto-closing and indentation
Comment toggling support

Future Plans

Language Server Protocol (LSP): Go-to-definition, hover info, autocomplete, diagnostics
Debugger: Step-through debugging for MSV scripts
Code Actions: Refactoring and quick fixes
Formatter: MSV code formatter
Test Explorer: Integration with VS Code's test UI

Contributing

Contributions are welcome! Please open an issue or pull request on GitHub.

License

MIT

MSV Language

msv-lang