Aster Lang TypeScript Compiler

TypeScript implementation of the Aster CNL (Controlled Natural Language) compiler pipeline.

Overview

Aster is a pragmatic, type-safe language with human-readable controlled natural language syntax. This package provides the pure TypeScript compiler infrastructure:

- Canonicalizer: Normalizes CNL source code
- Lexer: Tokenizes source with multi-language lexicon support
- Parser: Generates AST from token stream
- Core IR: Intermediate representation
- Type Checker: Static type analysis
- LSP Server: Language Server Protocol implementation

Installation

``bash
pnpm install @aster-cloud/aster-lang-ts
`

Quick Start

`typescript
import { canonicalize, lex, parse, lowerModule } from '@aster-cloud/aster-lang-ts';

// Compile pipeline
const source =
This module is greeting.

To greet with name, produce:
Return Text.concat("Hello, ", name).
;

const canonical = canonicalize(source);
const tokens = lex(canonical);
const ast = parse(tokens);
const core = lowerModule(ast);
`

Multi-Language Support

Aster supports writing policies in multiple natural languages:

`typescript
import { canonicalize, lex, parse } from '@aster-cloud/aster-lang-ts';
import { ZH_CN } from '@aster-cloud/aster-lang-ts/lexicons/zh-CN';

const zhSource =
【模块】问候。

问候 入参 姓名，产出：
返回「你好，」 加 姓名。
;

const tokens = lex(canonicalize(zhSource, ZH_CN), ZH_CN);
const ast = parse(tokens);
`

Supported languages:
- English (en-US) - Default
- Simplified Chinese (zh-CN)
- German (de-DE)

Current CNL Style

- Type inference is the default; examples avoid explicit type annotations.
- Operator-call chaining is removed. Use standard calls or infix operators.
- Statements end with periods, and block headers end with colons.

Documentation

- docs/overview.md
- docs/cnl-syntax.md
- docs/type-inference.md
- docs/operator-call.md
- docs/examples.md
- docs/contributing.md
- Localized docs:
- English (default): same list above.
- 简体中文: docs/zh/overview.md, docs/zh/cnl-syntax.md, docs/zh/type-inference.md, docs/zh/operator-call.md, docs/zh/examples.md, docs/zh/contributing.md
- Deutsch: docs/de/overview.md, docs/de/cnl-syntax.md, docs/de/type-inference.md, docs/de/operator-call.md, docs/de/examples.md, docs/de/contributing.md

Development

`bash


Install dependencies

pnpm install

Build

pnpm build

Run tests

pnpm test:unit

Start LSP server

pnpm lsp

REPL

pnpm repl
`

Project Structure

`
src/
├── canonicalizer.ts # Source normalization
├── lexer.ts # Tokenization
├── parser.ts # AST generation
├── ast.ts # AST definitions
├── lower_to_core.ts # Core IR lowering
├── core_ir.ts # Core IR definitions
├── typecheck/ # Type checker
├── lsp/ # Language Server Protocol
└── config/
└── lexicons/ # Multi-language lexicons
├── en-US.ts
├── zh-CN.ts
└── de-DE.ts
`

API Reference

$3

| Export | Description |
|--------|-------------|
| canonicalize(source, lexicon?) | Normalize CNL source |
| lex(source, lexicon?) | Tokenize source |
| parse(tokens) | Parse to AST |
| lowerModule(ast) | Convert AST to Core IR |
| typecheck(module) | Type check module |

$3

`typescript
import { EN_US } from '@aster-cloud/aster-lang-ts/lexicons/en-US';
import { ZH_CN } from '@aster-cloud/aster-lang-ts/lexicons/zh-CN';
import { DE_DE } from '@aster-cloud/aster-lang-ts/lexicons/de-DE';
``

License

MIT