ApolloVM

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ApolloVM is a portable VM (native, JS/Web, Flutter) that can parse, translate, and execute multiple languages such as Dart, Java, Kotlin, Go, C#, JavaScript, TypeScript, Lua, and Python. It also provides on-the-fly compilation to Wasm.

Use Cases

  • 🤖 MCP tool for LLMs — expose ApolloVM over MCP so an LLM can use it as a sandboxed reasoning scratchpad and validate generated code (parse, run, check output).
  • 🔄 Cross-language translation / porting — translate and regenerate source between any supported languages to prototype, migrate, or share logic across stacks.
  • 📱 Embedded scripting in Dart/Flutter — ship logic, UIs, and behavior that update live at runtime, with no rebuild or app-store redeploy.
  • 📐 Business rules & formulas — define pricing, discounts, validation, and eligibility logic as editable rules in a real, familiar language, evaluated safely at runtime — no hardcoding or custom expression engine to build and maintain.
  • 🔒 Sandboxed execution — run untrusted, user-supplied snippets isolated from the host, via the interpreter or compiled Wasm.
  • ⚙️ On-the-fly WebAssembly — compile loaded source to portable Wasm modules at runtime (browser or native) without any external toolchain.
  • 🎓 Playgrounds & education — build multi-language runners/REPLs that show the same program across languages and its translated output.
  • 🧪 Reference implementations / test oracles — write an algorithm once, then run or emit it across language targets to cross-check behavior.
  • 🌳 Polyglot AST tooling — parse multiple languages into one shared AST for analysis, transformation, and code generation.
  • 🪶 Small, multi-platform VM — runs on native, web/JS, and Flutter; the CLI compiles to a self-contained native binary under 10 MB with all features included.

Live Example

Experience ApolloVM in action right from your browser:

If you prefer to run the demo on your local machine:

Supported Features

ApolloVM can parse, execute (interpret), and translate (cross-compile) source code between all supported languages, and compile to WebAssembly on the fly.

Languages

Dart, Java 11, Kotlin, Go, C#, JavaScript, TypeScript, Lua and Python.

Any supported language can be translated to any other (e.g. Java → Dart, C# → Python, Kotlin → JavaScript, Go → Dart), and code can be regenerated back to its original language.

Core capabilities

  • Parsing of each language into a shared AST.
  • Execution: a tree-walking interpreter runs the AST directly.
  • Translation: regenerate the AST as source in any supported language.
  • Wasm compilation: compile to WebAssembly, including async/await (via Asyncify), classes (fields, constructors, instance & static methods, toString() dispatch, Object/dynamic boxing), exceptions, closures, lists/maps and GC types.

Control flow & operators

Legend: ✅ supported · 🧩 supported via the language's idiom · 🚧 not yet supported (exists in the language but not implemented yet) · 🚫 not applicable (the language has no such construct).

The Wasm column shows what the on-the-fly WebAssembly compiler currently supports (any source language is compiled through the same shared AST).

Feature Dart Java Kotlin Go C# JS TS Lua Python Wasm
if / else if / else ✅ ✅ ✅ ✅ ✅ ✅ ✅ ✅ ✅ ✅
for (C-style) ✅ ✅ 🚫 ✅ ✅ ✅ ✅ 🧩¹ 🚫 ✅
for-each / for-in ✅ ✅ ✅ ✅ ✅ ✅ ✅ ✅ ✅ ✅
while ✅ ✅ ✅ 🧩⁸ ✅ ✅ ✅ ✅ ✅ ✅
do / while ✅ ✅ ✅ 🧩⁹ ✅ ✅ ✅ 🧩² 🚫 ✅
switch / case ✅ ✅ 🧩³ ✅ ✅ ✅ ✅ 🚫 🧩⁴ ✅
break ✅ ✅ ✅ ✅ ✅ ✅ ✅ ✅ ✅ ✅
continue ✅ ✅ ✅ ✅ ✅ ✅ ✅ 🚫 ✅ ✅
try / catch / finally ✅ ✅ ✅ 🚧 ✅ ✅ ✅ 🚫 ✅ ✅
throw / raise ✅ ✅ ✅ 🚧 ✅ ✅ ✅ 🚫 ✅ ✅
async / await ✅ 🚫 🧩⁷ 🚫 ✅ ✅ ✅ 🚫 ✅ ✅
Ternary (? :) ✅ ✅ ✅ 🧩¹⁰ ✅ ✅ ✅ 🚫 ✅ ✅
Arithmetic (+ - * / %) ✅ ✅ ✅ ✅ ✅ ✅ ✅ ✅ ✅ ✅
Comparison / logical ✅ ✅ ✅ ✅ ✅ ✅ ✅ ✅ ✅ ✅
Bitwise (& | ^ << >> ~) ✅ ✅ 🧩⁵ 🧩¹¹ ✅ ✅ ✅ 🧩⁶ ✅ ✅
++ / --, compound assign ✅ ✅ ✅ ✅ ✅ ✅ ✅ ✅ ✅ ✅
Lambdas / closures ✅ ✅ ✅ ✅ ✅ ✅ ✅ ✅ ✅ ✅
Named / keyword arguments ✅ 🚫 ✅ 🚫 ✅ 🚫 🚫 🚫 ✅ ✅
Parameter default values ✅ 🚫 ✅ 🚫 ✅ 🚫 🚫 🚫 ✅ ✅
String interpolation / concat ✅ ✅ ✅ ✅ ✅ ✅ ✅ ✅ ✅ ✅
List & map / dict literals ✅ ✅ ✅ ✅ ✅ ✅ ✅ ✅ ✅ ✅
null / None / nil ✅ ✅ ✅ ✅ ✅ ✅ ✅ ✅ ✅ ✅

¹ Lua numeric-for (for i = a, b do).   ² Lua repeat … until.   ³ Kotlin when.   ⁴ Python match / case.   ⁵ Kotlin bitwise are infix functions: and/or/xor/shl/shr and .inv().   ⁶ Lua bitwise use &/|/~ (xor)/<</>> and unary ~ (Lua 5.3).   ⁷ Kotlin's async idiom is suspend / coroutines: ApolloVM generates suspend fun (dropping await) when translating to Kotlin, but does not yet parse Kotlin suspend. await unwraps the awaitable (Future<T> / Promise<T> / Task<T>) to T.   ⁸ Go has no while; the condition-only for cond {} is used.   ⁹ Go has no do/while; emitted as for { … if !cond { break } }.   ¹⁰ Go has no ?:/if-expression; ApolloVM emits an IIFE func() any { if c { return a } else { return b } }().   ¹¹ Go bitwise use &/|/^ (xor)/<</>>, unary ^ for NOT and &^ (AND-NOT). try/catch/throw (Go uses defer/recover/panic) and async/await (Go uses goroutines/channels) are not applicable / not implemented yet.

Classes, types & OOP

Same legend and Wasm column semantics as the table above.

Feature Dart Java Kotlin Go C# JS TS Lua Python Wasm
Classes ✅ ✅ ✅ 🧩⁷ ✅ ✅ ✅ 🚫 ✅ ✅
Fields (with initializers) ✅ ✅ ✅ 🧩⁸ ✅ ✅ ✅ 🧩¹ ✅ ✅
Constructors & instantiation (new Foo(...) / Foo(...)) ✅ ✅ ✅ 🧩⁹ ✅ ✅ ✅ 🧩¹ ✅ ✅
Methods ✅ ✅ ✅ ✅ ✅ ✅ ✅ ✅ ✅ ✅
Static / visibility modifiers ✅ ✅ 🧩³ 🧩¹⁰ ✅ 🧩² ✅ 🚫 🚫 🧩⁴
Inheritance (extends) / interfaces ✅ ✅ ✅ 🚧 ✅ ✅ ✅ 🚫 ✅ 🚧
Enums (rich: ctor args, fields, methods)⁶ ✅ ✅ ✅ 🚧 ✅ 🚫 ✅ 🚫 ✅ ✅⁶
Generics (generic classes + instantiation + type erasure) ✅ ✅ ✅ 🚧 ✅ 🚫 ✅ 🚫 🚫 🚧
Type inference (var / val / auto) ✅ ✅ ✅ ✅ ✅ 🚫 ✅ 🚫 🚫 ✅⁵
Extensions (methods + getters)¹¹ ✅ 🚫 ✅ 🚫 🧩¹² 🚫 🚫 🚫 🚫 🚧

¹ Lua is table-based: "fields" are table entries (obj.x), "constructors" are factory/setmetatable idioms, methods are function Obj:method.   ² JavaScript has static but no visibility keywords (privacy is by convention/closures).   ³ Kotlin private/public visibility round-trips; internal/protected are parsed but not preserved yet; no static (uses companion object, not yet supported).   ⁴ Wasm compiles static methods (exported as Class.method) and instance methods (called with a receiver); only static methods are callable as entry points, with no source-level visibility.   ⁵ Wasm consumes the already type-resolved AST, so var/val-typed code compiles unchanged.   ⁶ Each enum entry is a const instance of the enum's class (Dart enhanced enums): .index, .name, EnumName.values, identity ==, plus rich-enum constructor args, fields and methods. Java/Kotlin emit native rich enums; C#/TS/Python use a class + static-const-instances idiom; Wasm compiles entries to heap instances (a method chained directly on an entry needs a variable first). Breaking change: an entry is no longer an int — use .index (and .value for = N entries).   Generics are 🚫 for JS/Lua/Python: no static type syntax to parameterize.   ⁷ Go has no classes; a class is modeled as a type Name struct { ... } plus receiver methods func (o *Name) m(...) (the same idiom Lua uses for tables).   ⁸ Go struct types can't carry inline field initializers, so initializers are moved into the generated NewName factory.   ⁹ Go constructors/instantiation use a func NewName(...) *Name factory (built around the zero-valued composite literal &Name{}), and call sites read NewName(...), since Go has no new. Every struct gets a factory, so instantiation always resolves. Only the empty-brace composite literal is parsed; field-initializing literals (&Name{x: 1}) are not.   ¹⁰ Go has no static/visibility keywords: static methods become package-level funcs and visibility follows identifier capitalization. Inheritance, rich enums and generics (Go embedding/iota/[T any]) are 🚧 — not implemented for Go yet.   ¹¹ Members added to an existing type (a core type like int/String, or a user class) from outside its declaration: Dart extension E on T { ... }, Kotlin top-level fun T.m() and val T.g: R get(), C# static class E { static R M(this T self) }. A class member always wins over an extension member, and an extension is visible only within its own module (not carried across import). The languages marked 🚫 have no equivalent construct — prototype patching, monkey patching and metatables are not the same thing — so generating an extension for them throws UnsupportedSyntaxError rather than emitting a semantically different shim.   ¹² C# has no extension property, so an extension declaring a getter cannot be emitted as C#; its methods round-trip, with this/self translated both ways.

Per-language behavior is normalized to a shared AST, so types and constructs map cleanly when translating between languages (e.g. C# string ⇄ Dart String, Java List<Integer> ⇄ Dart List<int>).

Command Line Usage

You can use the executable apollovm to run, translate or compile source files, and to start the MCP and LSP servers.

First you should activate the package globally:

$> dart pub global activate apollovm

Now you can use the apollovm Dart executable:

$> apollovm help

ApolloVM - A compact VM for Dart, Java, Kotlin, Go, C#, JavaScript, TypeScript, Lua and Python.

Usage: apollovm <command> [arguments]

Global options:
-h, --help       Print this usage information.
-v, --version    Show ApolloVM version.

Available commands:
  compile     Compile a source file to a binary target (WebAssembly).
  lsp         Start the ApolloVM Language Server (LSP) over stdin/stdout.
  mcp         ApolloVM MCP (Model Context Protocol) server and tools.
  run         Run a source file.
  translate   Translate a source file.

Run "apollovm help <command>" for more information about a command.

To run a Java file:

$> apollovm run -v test/hello-world.java foo
## [RUN]        File: 'test/hello-world.java' ; language: java11 > main( [foo] )
Hello World!
- args: [foo]
- a0: foo

To translate a Java file to Dart:

$> apollovm translate -v --target dart test/hello-world.java
## [TRANSLATE]  File: 'test/hello-world.java' ; language: java11 > targetLanguage: dart
<<<< [SOURCES_BEGIN] >>>>
<<<< NAMESPACE="" >>>>
<<<< CODE_UNIT_START="/test/hello-world.java" >>>>
class Hello {

  static void main(List<String> args) {
    var a0 = args[0];
    print('Hello World!');
    print('- args: $args');
    print('- a0: $a0');
  }

}
<<<< CODE_UNIT_END="/test/hello-world.java" >>>>
<<<< [SOURCES_END] >>>>

The same commands work for any supported language — the language is detected from the file extension (.dart, .java, .kt, .go, .cs, .js, .ts, .lua, .py), and --target accepts any of them.

Compiling ApolloVM executable.

Dart supports compilation to native self-contained executables.

To have a fast and small executable of ApolloVM, just clone the project and compile it:


## Go to a directory to clone the project (usually a workspace):
$> cd ./some-workspace/

## Git clone the project:
$> git clone https://github.com/ApolloVM/apollovm_dart.git

## Enter the project:
$> cd ./apollovm_dart

## Compile ApolloVM executable:
$> dart compile exe bin/apollovm.dart

## Copy the binary to your preferred PATH:
$> cp bin/apollovm.exe /usr/bin/apollovm

Now you can use apollovm as a self-executable, even if you don't have Dart installed.

Package Usage

The examples below load source code into the VM, execute it, and regenerate it in another language. The first two (Dart and Java) show the full host code; the host code is identical for every language — only the language id passed to SourceCodeUnit(...) and vm.createRunner(...) changes.

Language: Dart

Loading Dart source code, executing it, and then converting it to Java 11:

import 'package:apollovm/apollovm.dart';

void main() async {
  var vm = ApolloVM();

  var codeUnit = SourceCodeUnit(
          'dart',
          r'''
      
      class Foo {
      
          static int main(List<Object> args) {
            var title = args[0];
            var a = args[1];
            var b = args[2] ~/ 2;
            var c = args[3] * 3;
            
            if (c > 120) {
              c = 120 ;
            }
            
            var str = 'variables> a: $a ; b: $b ; c: $c' ;
            var sumAB = a + b ;
            var sumABC = a + b + c;
            
            print(str);
            print(title);
            print(sumAB);
            print(sumABC);
            
            // Map:
            var map = <String,int>{
            'a': a,
            'b': b,
            'c': c,
            'sumAB': sumAB,
            "sumABC": sumABC,
            };
            
            print('Map: $map');
            print('Map `b`: ${map['b']}');
            
            return map['sumABC'];
          }
          
      }
      
      ''',
          id: 'test');

  var loadOK = await vm.loadCodeUnit(codeUnit);

  if (!loadOK) {
    print("Can't load source!");
    return;
  }

  print('---------------------------------------');

  var dartRunner = vm.createRunner('dart')!;

  // Map the `print` function in the VM:
  dartRunner.externalPrintFunction = (o) => print("» $o");

  var astValue = await dartRunner.executeClassMethod(
    '',
    'Foo',
    'main',
    positionalParameters: [
      ['Sums:', 10, 30, 50]
    ],
  );

  var result = astValue.getValueNoContext();
  print('Result: $result');

  print('---------------------------------------');

  // Regenerate code in Java11:
  var codeStorageJava = vm.generateAllCodeIn('java11');
  var allSourcesJava = await codeStorageJava.writeAllSources();
  print(allSourcesJava);
}

Note: the parsed function print was mapped as an external function.

Output:

---------------------------------------
» variables> a: 10 ; b: 15 ; c: 120
» Sums:
» 25
» 145
» Map: {a: 10, b: 15, c: 120, sumAB: 25, sumABC: 145}
» Map `b`: 15
Result: 145
---------------------------------------
<<<< [SOURCES_BEGIN] >>>>
<<<< NAMESPACE="" >>>>
<<<< CODE_UNIT_START="/test" >>>>
class Foo {

  static int main(Object[] args) {
    var title = args[0];
    var a = args[1];
    var b = args[2] / 2;
    var c = args[3] * 3;
    if (c > 120) {
        c = 120;
    }

    var str = "variables> a: " + a + " ; b: " + b + " ; c: " + c;
    var sumAB = a + b;
    var sumABC = a + b + c;
    print(str);
    print(title);
    print(sumAB);
    print(sumABC);
    var map = new HashMap<String,int>(){{
      put("a", a);
      put("b", b);
      put("c", c);
      put("sumAB", sumAB);
      put("sumABC", sumABC);
    }};
    print("Map: " + map);
    print("Map `b`: " + String.valueOf( map["b"] ));
    return map["sumABC"];
  }

}
<<<< CODE_UNIT_END="/test" >>>>
<<<< [SOURCES_END] >>>>

Language: Java 11

Loading Java 11 source code, executing it, and then converting it to Dart:

import 'package:apollovm/apollovm.dart';

void main() async {
  var vm = ApolloVM();

  var codeUnit = SourceCodeUnit(
          'java11',
          r'''
            class Foo {
               static public void main(Object[] args) {
                 var title = args[0];
                 var a = args[1];
                 var b = args[2];
                 var c = args[3];
                 var sumAB = a + b ;
                 var sumABC = a + b + c;
                 print(title);
                 print(sumAB);
                 print(sumABC);
                 
                 // Map:
                 var map = new HashMap<String,int>(){{
                  put("a", a);
                  put("b", b);
                  put("c", c);
                  put("sumAB", sumAB);
                  put("sumABC", sumABC);
                }};
                 
                print("Map: " + map);
               }
            }
          ''',
          id: 'test');

  var loadOK = await vm.loadCodeUnit(codeUnit);

  if (!loadOK) {
    throw StateError('Error parsing Java11 code!');
  }

  var javaRunner = vm.createRunner('java11')!;

  // Map the `print` function in the VM:
  javaRunner.externalPrintFunction = (o) => print("» $o");

  await javaRunner.executeClassMethod('', 'Foo', 'main', positionalParameters: [
    ['Sums:', 10, 20, 30]
  ]);

  print('---------------------------------------');

  // Regenerate code:
  var codeStorageDart = vm.generateAllCodeIn('dart');
  var allSourcesDart = await codeStorageDart.writeAllSources();
  print(allSourcesDart.toString());
}

Note: the parsed function print was mapped as an external function.

Output:

» Sums:
» 30
» 60
» Map: {a: 10, b: 20, c: 30, sumAB: 30, sumABC: 60}
---------------------------------------
<<<< [SOURCES_BEGIN] >>>>
<<<< NAMESPACE="" >>>>
<<<< CODE_UNIT_START="/test" >>>>
class Foo {

  static void main(List<Object> args) {
    var title = args[0];
    var a = args[1];
    var b = args[2];
    var c = args[3];
    var sumAB = a + b;
    var sumABC = a + b + c;
    print(title);
    print(sumAB);
    print(sumABC);
    var map = <String,int>{'a': a, 'b': b, 'c': c, 'sumAB': sumAB, 'sumABC': sumABC};
    print('Map: $map');
  }

}
<<<< CODE_UNIT_END="/test" >>>>
<<<< [SOURCES_END] >>>>

The remaining languages follow the same pattern, so only each language's source snippet is shown. Two notes that apply below: instance (non-static) methods — Kotlin's greet, Go receiver methods, Lua's Foo:main, Python's self methods — need a class instance, provided via classInstanceFields: const {}; and each language's native print (println, fmt.Println, …) is normalized to the VM's print, mapped as an external function.

Language: Kotlin

class Foo {
  fun greet(name: String, count: Int) {
    val msg = "Hello $name, you have $count messages."
    println(msg)
  }
}

Kotlin support reaches parity with the Java feature set: top-level and class fun declarations, val/var with type inference, if/else, for (x in …), while, listOf/mapOf literals, and "$x" / "${expr}" string templates — all translatable to Dart, Java or back to Kotlin.

Language: Go

type Foo struct {
}

func (o *Foo) greet(name string, count int) {
  msg := "Hello " + name + ", you have " + count + " messages."
  fmt.Println(msg)
}

Go is bidirectional: ApolloVM parses .go/go source into the AST, executes it, and generates idiomatic Go — package main with an import "fmt" when needed, type-after-name declarations (func f(a int) int, x := …), for-only control flow (for cond {} for while, for { … if !cond { break } } for do/while, for _, x := range xs {} for for-each), Go switch (no fall-through), slices/maps ([]int{…}, map[K]V{…}) and closures (func(x int) int { … }). Classes map to the Go idiom — a type Name struct { … } plus receiver methods func (o *Name) m(...) — so object-oriented code round-trips to and from Dart, Java, Kotlin, C#, JavaScript, TypeScript and Python.

Language: JavaScript

class Foo {
  static greet(name, count) {
    let msg = `Hello ${name}, you have ${count} messages.`;
    print(msg);
  }
}

JavaScript is fully bidirectional: ApolloVM can parse .js/javascript source into the AST, execute it, and generate idiomatic modern ES (let/const, template literals, for...of, top-level functions, ===/!==) from any loaded AST (Dart, Java, or JavaScript).

Language: TypeScript

TypeScript is supported as a superset of JavaScript: everything JavaScript supports, plus type annotations (variables, parameters, return types, fields), interfaces, enums, and access modifiers (public/private/protected/readonly/static/ abstract).

class Foo {
  static greet(name: string, count: number): void {
    let msg: string = `Hello ${name}, you have ${count} messages.`;
    print(msg);
  }
}

TypeScript is bidirectional: ApolloVM parses .ts/typescript source (including interface, enum, and member modifiers) into the AST, executes it, and generates idiomatic TypeScript with type annotations. The same interface/enum/modifier constructs are also supported in Dart (abstract class, enum, static/final), so they cross-translate between Dart, TypeScript and JavaScript.

Language: Lua

Foo = {}
Foo.__index = Foo

function Foo:main(title, a, b, c)
  local sumAB = a + b
  local sumABC = a + b + c
  print(title)
  print(sumAB)
  print(sumABC)
end

Lua is bidirectional: ApolloVM parses .lua source into the AST, executes it, and generates idiomatic Lua (keyword-delimited blocks with end, local variables, .. concatenation, and/or/not/~=, and generic for ... in ipairs(...)) from any loaded AST. Object-oriented code uses the conventional table + metatable form (Name = {}, Name.__index = Name, function Name:method(...)), so classes round-trip to and from Dart, Java, Kotlin, JavaScript and TypeScript.

Language: Python

class Foo:
    def greet(self, name, count):
        msg = f'Hello {name}, you have {count} messages.'
        print(msg)

Python is bidirectional: ApolloVM parses .py/python source into the AST, executes it, and generates strict, idiomatic Python 3. Indentation-significant blocks are handled by an INDENT/DEDENT/NEWLINE pre-tokenizer, and generation emits PEP-484 type hints when the AST type is statically known (def f(x: int) -> int:, x: str = ..., List[T]/Dict[K, V]) with a dynamic fallback. Supported constructs include functions, self-based methods and class declarations, if/elif/else, while, for ... in, try/except/finally with raise, lists & dicts, f-string interpolation, // integer division, and/or/not, True/False/None, and import/from ... import — all cross-translatable with Dart, Java, Kotlin, JavaScript, TypeScript and Lua.

Wasm Support

ApolloVM can compile its AST tree to WebAssembly (Wasm). This means that parsed code loaded into the VM can be compiled on the fly, without the need for any third-party tools.

  • Status: Wasm support is under active development. It already compiles a broad subset of the AST — functions, full control flow (if/for/for-each/while/do-while/switch/ break/continue/ternary), arithmetic/comparison/logical/bitwise operators, try/catch/throw, classes, closures, lists/maps, and async/await (via Asyncify); see the feature table. Constructs not yet compiled to Wasm are limited to a few higher-level features (e.g. non-integer switch).

Example compiling Dart code to WebAssembly (Wasm):

import 'dart:typed_data';
import 'package:apollovm/apollovm.dart';

void main() async {
  var wasmBytes = await compileToWasm('dart', '''
    
    int main( int a , double b ) {
      var x = (a + b) / 2 ;
      if (x > 1000) {
        return -1;
      }
      return x ;
    }
    
  ''');

  // Execute or save the compiled Wasm...
}

Future<Uint8List> compileToWasm(String codeLanguage, String code) async {
  var vm = ApolloVM();

  var codeUnit = SourceCodeUnit(codeLanguage, code, id: 'test');

  Object? loadError;
  var loadOK = false;
  try {
    loadOK = await vm.loadCodeUnit(codeUnit);
  } catch (e, s) {
    loadError = e;
  }

  if (!loadOK) {
    throw StateError(
            "Can't load source! Language: $codeLanguage\n\n$loadError");
  }

  var storageWasm = vm.generateAllIn<BytesOutput>('wasm');
  var wasmModules = await storageWasm.allEntries();

  var namespace0 = wasmModules.values.first;

  var wasmModule = namespace0.entries.first;
  var wasmOutput = wasmModule.value; // BytesOutput

  print(wasmOutput.toString()); // Show bytes description.

  var wasmBytes = wasmOutput.output();
  return wasmBytes;
}

Generated Wasm bytes with description:


  ## Wasm Magic:
  [0 97 115 109]
  ## Version 1:
  [1 0 0 0]
  ## Section: Type:
      ## Section Type ID:
      [1]
      ## Bytes block length:
      [7]
      ## Functions signatures:
        ## Types count:
        [1]
          ## Type: function:
          [96]
          ## Parameters types:
          [2 126 124]
          ## Return value:
          [1 126]
  ## Section: Function:
      ## Section Function ID:
      [3]
      ## Bytes block length:
      [2]
      ## Functions type indexes:
      [1 0]
  ## Section: Export:
      ## Section Export ID:
      [7]
      ## Bytes block length:
      [8]
      ## Exported types:
        ## Exported types count:
        [1]
        ## Export function:
          ## Function name(`main`):
          [4 109 97 105 110]
          ## Export type(function):
          [0]
          ## Type index(0):
          [0]
  ## Section: Code:
      ## Section Code ID:
      [10]
      ## Bytes block length:
      [35]
      ## Functions bodies:
        ## Bodies count:
        [1]
          ## Bytes block length:
          [33]
          ## Function body:
              ## Local variables count:
              [1]
              ## Declared variable count:
              [1]
              ## Declared variable type(f64):
              [124]
                  ## [OP] local get: 0 $a:
                  [32 0]
                ## [OP] convert i64 to f64 signed:
                [185]
                  ## [OP] local get: 1 $b:
                  [32 1]
                ## [OP] operator: add(f64):
                [160]
                ## [OP] push constant(i64): 2:
                [66 2]
              ## [OP] convert i64 to f64 signed:
              [185]
              ## [OP] operator: divide(f64):
              [163]
              ## [OP] local set: 2 $x:
              [33 2]
                ## [OP] local get: 2 $x:
                [32 2]
                ## [OP] push constant(i64): 1000:
                [66 232 7]
              ## [OP] convert i64 to f64 signed:
              [185]
              ## [OP] operator: greaterThan(f64):
              [100]
              ## [OP] if ( x > (int) 1000 ):
              [4 64]
              ## [OP] push constant(i64): -1:
              [66 127]
              ## [OP] return value: (int) -1:
              [15]
              ## [OP] if end:
              [11]
              ## [OP] local get: 2 $x (return):
              [32 2]
              ## f64TruncateToI64Signed:
              [176]
              ## [OP] return variable: 2 $x:
              [15]
              ## Code body end:
              [11]
  • NOTE: When compiling to WebAssembly, ApolloVM keeps track of the stack and performs automatic type casting to facilitate operations between different types or return values.

MCP Server

ApolloVM ships an MCP (Model Context Protocol) server that exposes the VM as a programmable execution engine for AI agents. Agents can parse, execute, translate, compile, and inspect code across all supported languages through MCP tools.

Start it over stdio (the standard local transport):

apollovm mcp serve

or over HTTP/SSE for networked agents:

apollovm mcp serve --http 8080          # binds 127.0.0.1:8080, SSE at /sse

Example MCP client configuration (e.g. for an agent/IDE):

{
  "mcpServers": {
    "apollovm": { "command": "apollovm", "args": ["mcp", "serve"] }
  }
}

mcp subcommands

Subcommand Purpose
mcp serve Run the MCP server over stdio (default) or HTTP/SSE (--http <port>).
mcp list List the available tools (names, descriptions, input schemas) as JSON.
mcp call <tool> Invoke one tool once and print its JSON result — source via --source/--file/stdin, args via flags. Use it from scripts/CI with no MCP client.
mcp info Print server metadata: version, MCP protocol, transports, languages, limits.
mcp schema [tool] Print the JSON input schema(s) for one or all tools.
mcp doctor Check the server/tools and report capabilities (e.g. whether the native wasm_run lib is available to run compiled Wasm). 
# Run a tool from the shell without an MCP client:
apollovm mcp call apollovm.execute --language dart \
  --source 'int main(List a){ print("hi"); return 42; }'

apollovm mcp call apollovm.translate --from go --to dart --file main.go

Tools

Tool Input Output
apollovm.parse language, source parse ok, diagnostics, summary (classes/functions/imports)
apollovm.execute language, source, function?, className?, args?, timeoutMs? result, output (console), diagnostics
apollovm.translate from, to, source generated source
apollovm.ast language, source, maxDepth? full AST as JSON
apollovm.symbols language, source symbol graph (functions/classes/fields/methods/constructors)
apollovm.types language, source deduplicated type table (class/builtin/unknown)
apollovm.wasm language, source WebAssembly modules as base64 bytes

Supported language values: dart, java, kotlin, go, csharp, javascript, typescript, lua, python, wasm.

Code-inspection tools (LSP)

The apollovm.lsp.* tools let an agent inspect code the way an editor does — backed by ApolloVM's in-process Language Server (results carry precise LSP line/character ranges). They accept the same language values above (except wasm).

Tool Input Output
apollovm.lsp.diagnostics language, source, uri? diagnostics (with ranges), ok
apollovm.lsp.symbols language, source, uri? document outline (nested symbols + ranges)
apollovm.lsp.hover language, source, line, character, uri? hover (signature, type, doc)
apollovm.lsp.definition language, source, line, character, uri? definition location
apollovm.lsp.references language, source, line, character, includeDeclaration?, uri? references
apollovm.lsp.completion language, source, line, character, uri? completion items
apollovm.lsp.workspaceSymbols query, files: [{uri, source, language?}] matching symbols across the files

apollovm.lsp.workspaceSymbols takes multiple in-memory files, enabling codebase-wide symbol search. See example/apollovm_example_mcp_lsp.dart.

Workspace / repository tools

Start the server with --workspace <dir> to additionally expose tools that work on real files in a repository, so a coding agent can explore, search, navigate and version-control the codebase without shelling out to POSIX:

apollovm mcp serve --workspace .                       # read-only
apollovm mcp serve --workspace . --allow-write --allow-git-write
Group Tools Replaces
apollovm.fs.* read, list, find, stat, write, edit, mkdir, move, delete cat/ls/find/sed/mv/rm
apollovm.search.* text (regex), symbols (language-aware) grep
apollovm.code.* outline, definition, references, hover, diagnostics, workspaceSymbols editor navigation
apollovm.git.* status, diff, log, show, blame, add, commit, checkout, restore the git CLI

search.symbols and code.* reuse ApolloVM's parsers/LSP, so they match declarations (not comment/string text) with precise ranges. Everything is read-only by default; writes and git mutations are opt-in (--allow-write / --allow-git-write). Paths are confined to the workspace root (../absolute rejected), and fs.edit supports an atLine safety anchor. See doc/MCP.md for details.

These tools are a thin JSON layer over a standalone repository library — the features are not MCP-exclusive. A web IDE, editor, agent or test can use them directly via RepositoryService (a typed façade over a pluggable RepositoryAdapter):

import 'package:apollovm/apollovm_repository_io.dart'; // web: apollovm_repository.dart

final repo = RepositoryService(
  LocalRepositoryAdapter('.'),                 // or InMemoryRepositoryAdapter(files)
  config: const RepoConfig(allowWrite: true),
);
final outline = await repo.outline('lib/foo.dart');   // typed, language-aware
final hits = await repo.searchText('TODO', glob: 'lib/**');
print(await repo.gitStatus());
await repo.close();

RepositoryAdapter backends: LocalRepositoryAdapter (dart:io + git), InMemoryRepositoryAdapter (web-safe), or a future remote/web backend — enabling file edits and git commands from the browser. A PermissionGuard enforces the RepoConfig uniformly across backends.

Security model

  • File/network access is denied by construction — executed code is only ever granted print; no filesystem or socket bridge is exposed, and tools operate on inline source strings only (never a path).
  • Timeout / CPU — apollovm.execute runs inside a killable isolate by default, so a hard wall-clock timeout is enforced even against a runaway synchronous loop (--timeout-ms, default 5000). Other tools run in-process. Which tools use an isolate is configurable (--isolate-tools).
  • Input/output caps — --max-source-chars (default 262144) and --max-output-chars (default 65536) bound request/response size.
  • Memory — Dart has no per-isolate hard heap cap, so memory limiting is best-effort; run the process with --old_gen_heap_size=<MB> for a hard ceiling.

The embeddable API lives in package:apollovm/apollovm_mcp.dart (ApolloMcpServer, serveStdio, HttpSseTransport, McpLimits). See doc/MCP.md for the full tool schemas and protocol notes.

Language Server (LSP)

ApolloVM ships a Language Server (LSP 3.17) for its supported languages, included in the apollovm package as the separate library package:apollovm/apollovm_lsp.dart.

Start it over stdio (for local editors):

apollovm lsp

The library imports no dart:io, so a browser IDE or an AI agent can embed the server and drive it with decoded JSON-RPC messages via MessageLspEndpoint (StreamLspEndpoint provides Content-Length framing for stdio/sockets):

import 'package:apollovm/apollovm_lsp.dart';

final endpoint = MessageLspEndpoint((msg) => hostPort.send(msg)); // outgoing
final server = LspServer(endpoint);
endpoint.receive(incomingMessage); // deliver each incoming JSON-RPC object

To consume the server, use LspClient. It correlates responses to requests, streams server-pushed diagnostics, and offers typed helpers (hover, definition, documentSymbol, completion, references, documentHighlight, prepareRename, rename, workspaceSymbol). LspClient.inProcess() pairs a client with a fresh server in the same isolate — no subprocess, no dart:io:

import 'package:apollovm/apollovm_lsp.dart';

final client = LspClient.inProcess();
client.diagnostics.listen((d) => print('${d.uri}: ${d.diagnostics.length} problems'));

await client.initialize();
client.initialized();
client.didOpen('file:///Foo.dart', source);

final hover = await client.hover('file:///Foo.dart', Position(2, 13));
print(hover?.contents.value);

await client.shutdown();
client.exit();

For an out-of-process server, wrap its transport instead — LspClient(StreamLspEndpoint(process.stdout, process.stdin))..start().

In-process API — no socket, no handshake (web / agents)

For the simplest embedding, use LspService: a document-oriented facade over an in-process server. There is no transport to wire, no socket to open and no initialize handshake to run by hand — construct it, hand it code, ask questions. Being dart:io-free, it runs unchanged in the browser.

import 'package:apollovm/apollovm_lsp.dart';

final lsp = LspService();

// One-shot: analyze a buffer and get its diagnostics.
final errors = await lsp.analyze('file:///Foo.dart', source);

// Or query features against the current buffer.
final hover = await lsp.hover('file:///Foo.dart', Position(2, 13));
final outline = await lsp.documentSymbols('file:///Foo.dart');
final edit = await lsp.rename('file:///Foo.dart', Position(2, 13), 'compute');

lsp.change('file:///Foo.dart', edited); // update as the buffer changes
await lsp.dispose();

LspService exposes analyze, open/change/close, a diagnostics stream, and typed hover, definition, documentSymbols, completion, references, documentHighlight, prepareRename, rename and workspaceSymbols. Use LspService.wrap(client) to layer the same convenience over a client connected to a remote (out-of-process) server.

Runnable walkthroughs are in example/apollovm_example_lsp_api.dart (the LspService API) and example/apollovm_example_lsp.dart (the lower-level LspClient).

A minimal VS Code client, an example workspace and a latency benchmark live in the repository's lsp/ directory (not part of the published package) — see lsp/README.md for features, design and editor setup.

Module Imports & Dart Package Importer

ApolloVM has a language-agnostic module import system: import declarations in loaded code resolve through pluggable ModuleLoaders (in-memory, filesystem, or custom). See doc/module_resolution.md.

For Dart code, the opt-in library package:apollovm/apollovm_pub.dart adds a package: importer that resolves dependencies from a local package_config.json (PackageConfigProvider) or directly from pub.dev (PubDevProvider, web-compatible) — see example/apollovm_example_pub_importer.dart. It is intentionally not exported from package:apollovm/apollovm.dart, so VMs that don't import it stay fully sandboxed.

See Also

ApolloVM uses PetitParser for Dart to define the grammars of the languages and to analyze the source codes.

Features and bugs

Please file feature requests and bugs at the issue tracker.

Contribution

Any help from the open-source community is always welcome and needed:

  • Have an issue? Please fill a bug report 👍.
  • Feature? Request with use cases 🤝.
  • Like the project? Promote, post, or donate 😄.
  • Are you a developer? Fix a bug, add a feature, or improve tests 🚀.
  • Already helped? Many thanks from me, the contributors and all project users 👏👏👏!

Contribute an hour and inspire others to do the same.

TODO

  • JavaScript: extended support (destructuring, spread, this.x constructor parameters, full ESM modules). Named arrow functions (const f = (a, b) => a + b;), anonymous arrow callbacks/closures ((x) => x * 2), the ternary operator (c ? a : b), and async/await are already supported.

  • TypeScript: extended support (union/intersection types, type aliases, parameter properties, decorators). Type annotations, interface, enum (incl. member access at runtime), generic classes/instantiation, and access modifiers (public/private/protected/readonly/static/abstract) are already supported.

  • Lua: extended support (multiple assignment/returns, varargs, non-ipairs numeric-for round-tripping, and hand-written metatable styles beyond the Name = {} / function Name:method convention).

  • Python: extended support (comprehensions, decorators, with statements, *args/**kwargs, multiple assignment/returns). Functions, classes/self-methods, if/elif/else, while, for ... in, try/except/finally + raise, lists & dicts, f-strings, keyword arguments, lambda expressions, conditional expressions (a if c else b), and import/from ... import are already supported.

  • Go: extended support (panic/recover/defer for try/catch/throw, interfaces + struct embedding for inheritance, const/iota enums, and [T any] generics). Top-level and struct receiver funcs, struct types + fields + factory constructors, var/:= with type inference, if/else if/else, for (C-style, condition-only, range, infinite), switch, slices/maps, closures, string + concatenation, and fmt.Println (normalized to print) are already supported.

  • Full Wasm support:

Author

Graciliano M. Passos: gmpassos@GitHub.

Don't be shy, show some love, and become our GitHub Sponsor. Your support means the world to us, and it keeps the code caffeinated! ☕✨

Thanks a million! 🚀😄

License

Apache License - Version 2.0

Libraries

apollovm
A portable virtual machine for Dart, web (JavaScript), and Flutter.
apollovm_lsp
ApolloVM Language Server (LSP 3.17) — editor/agent tooling for ApolloVM sources.
apollovm_mcp
MCP (Model Context Protocol) server for ApolloVM.
apollovm_mcp_io
Native (dart:io) MCP server extras for ApolloVM.
apollovm_pub
Optional Dart package importer for ApolloVM.
apollovm_repository
ApolloVM repository features — read, search, navigate, edit and version-control a codebase through a pluggable RepositoryAdapter.
apollovm_repository_io
Native (dart:io) repository extras for ApolloVM.