codegen.mbt

Generic code generation library for MoonBit with abstract IR (Intermediate Representation).

Features

• Abstract IR: Define types, structs, enums, functions once, emit to multiple targets
• Multi-language emitters: MoonBit, TypeScript, Rust, Protocol Buffers, JSON Schema, FlatBuffers, Zod
• Fluent builders: Easy-to-use builder pattern for constructing IR
• Validation: Generate validation code from JSON Schema

Installation

moon add mizchi/codegen

Usage

// Build a module using fluent API
let module = @builder.ModuleBuilder::new()
  .with_name("example")
  .add_struct(
    @builder.StructBuilder::new("User")
      .add_field("id", @ir.Type::int())
      .add_field("name", @ir.Type::string())
      .add_field("email", @ir.Type::optional(@ir.Type::string()))
      .build()
  )
  .add_enum(
    @builder.EnumBuilder::new("Status")
      .add_unit_variant("Active")
      .add_unit_variant("Inactive")
      .add_variant("Pending", [("reason", @ir.Type::string())])
      .build()
  )
  .build()

// Emit to MoonBit
let moonbit_code = @emit.MoonBitEmitter::new().emit_module(module)

// Emit to TypeScript
let ts_code = @emit.TypeScriptEmitter::new().emit_module(module)

// Emit to Rust
let rust_code = @emit.RustEmitter::new().emit_module(module)

Supported Emitters

Emitter	Output
MoonBitEmitter	MoonBit source code
TypeScriptEmitter	TypeScript interfaces and types
RustEmitter	Rust structs and enums
ProtobufEmitter	Protocol Buffers v3 schema
JsonSchemaEmitter	JSON Schema
FlatBuffersEmitter	FlatBuffers schema
ZodEmitter	Zod validation schemas

IR Types

pub enum Type {
  Primitive(String)      // "Int", "String", "Bool", etc.
  Optional(Type)         // Option[T]
  Array(Type)            // Array[T]
  Map(Type, Type)        // Map[K, V]
  Named(String, Array[Type]) // Custom types with generics
  Function(Array[Type], Type) // (A, B) -> C
  Tuple(Array[Type])     // (A, B, C)
  Error(Type)            // Error type for raise
}

Packages

• @ir - Core IR types (Type, Struct, Enum, Function, Module, etc.)
• @builder - Fluent builders (ModuleBuilder, StructBuilder, EnumBuilder, FunctionBuilder)
• @emit - Code emitters for various target languages
• @utils - Utility functions (naming conventions, escaping)

License

MIT