DScript

Open-source, object-oriented, JavaScript-like scripting language implemented in C#.

Source is compiled to bytecode and executed on a stack-based virtual machine with a peephole optimiser. Lexically scoped closures, generators, async/await, and a CommonJS/ES module system are built in. An optional standard library (DScript.Extras) provides a Node.js-style API surface.

Installation

dotnet add package DScript
dotnet add package DScript.Extras   # optional standard library

Quick example

using DScript;
using DScript.Extras;

var engine = new ScriptEngine();
new EngineFunctionLoader().RegisterFunctions(engine);

engine.Execute(@"
    function greet(name) {
        return `Hello, ${name}!`;
    }
");

var fn = engine.Root.GetParameter("greet");
var result = engine.CallFunction(fn, null, new ScriptVar("world")).String;
// result == "Hello, world!"

// The same engine, from script side
var nums = [1, 2, 3, 4, 5];
var evens = nums.filter(n => n % 2 === 0);   // [2, 4]
var sum   = nums.reduce((a, n) => a + n, 0); // 15

async function load() {
    var data = await Promise.resolve({ ok: true });
    return data.ok;
}

Documentation

Full documentation is on the DScript Wiki:

Topic	Page
ScriptEngine API, compiling, calling functions, state serialisation	Engine
Language reference — syntax, types, operators, classes, generators, async	Language
Standard library (console, Math, fs, fetch, crypto, …)	Standard Library
CommonJS require and ES module import	Modules
Wall-clock and instruction-count limits	Resource Limits
EnginePermissions sandbox flags	Permissions
Exposing C# objects to scripts with [ScriptVisible]	Host Objects
Step debugger and IDebugger interface	Debugger
Bytecode serialisation and source maps	Bytecode
Interactive REPL	REPL

Building

dotnet build --configuration Release

Both net8.0 and net10.0 targets must build cleanly. Run the test suite with:

dotnet test DScript.Test --configuration Release

Licence

MIT