Skip to content

Grammar School

A multi-language framework for building tiny LLM-friendly DSLs

Grammar School is a lightweight, multi-language framework for creating small, precise, LLM-friendly domain-specific languages (DSLs). It provides a simple way to define grammar rules, map DSL methods to implementations, and execute DSL programs through a clean parser → AST → interpreter → execute pipeline.

Features

  • 🎯 Simple Grammar Definition - Define grammars via strings or structured combinators
  • 🔗 Method Mapping - Map DSL methods to implementations with decorators/annotations
  • 🔄 Complete Pipeline - Parse → Interpret → Execute workflow
  • 🌍 Multi-Language - Independent implementations in Python and Go
  • 🤖 LLM-Friendly - Designed for LLM-generated DSL code
  • 📦 Lightweight - Minimal dependencies, focused API
  • 🔧 OpenAI CFG Integration - Built-in utilities for GPT-5 Context-Free Grammar constraints

Quick Example

from grammar_school import Grammar, method

class MyDSL(Grammar):
    @method
    def greet(self, name):
        print(f"Hello, {name}!")

dsl = MyDSL()
dsl.execute('greet(name="World")')
# Output: Hello, World!

type MyDSL struct{}

func (d *MyDSL) Greet(args gs.Args, ctx *gs.Context) ([]gs.Action, *gs.Context, error) {
    name := args["name"].Str
    action := gs.Action{
        Kind: "greet",
        Payload: map[string]interface{}{
            "name": name,
        },
    }
    return []gs.Action{action}, ctx, nil
}

type MyRuntime struct{}

func (r *MyRuntime) ExecuteAction(ctx context.Context, a gs.Action) error {
    fmt.Printf("Hello, %v!\n", a.Payload["name"])
    return nil
}

dsl := &MyDSL{}
engine, _ := gs.NewEngine("", dsl, parser)
runtime := &MyRuntime{}
plan, _ := engine.Compile(`greet(name="World")`)
engine.Execute(context.Background(), runtime, plan)
// Output: Hello, World!

Architecture

DSL Code (string)
   ↓
Parse → CallChain (AST)
   ↓
Interpret → Execute methods directly

All implementations follow the same conceptual design, ensuring consistency across languages while remaining independent.

Installation

pip install grammar-school

cd go
go mod download

Documentation

License

MIT License - see LICENSE file for details.