@domainlang/language

Core language library for DomainLang - a Domain-Driven Design modeling language built with Langium.

Features

• 🔤 Parser - Full DomainLang grammar with error recovery
• ✅ Validation - Semantic validation for DDD best practices
• 🔗 Linking - Cross-reference resolution across files and packages
• 🔍 Model Query SDK - Programmatic access to DDD models with fluent queries
• 🌐 Browser Support - Works in Node.js and browser environments

Installation

npm install @domainlang/language

Quick Start

Parse and Query Models

import { loadModelFromText } from '@domainlang/language/sdk';

const { query } = await loadModelFromText(`
  Domain Sales {
    vision: "Enable seamless commerce"
  }
  
  bc OrderContext for Sales as Core by SalesTeam {
    description: "Handles order lifecycle"
  }
`);

// Query bounded contexts
const coreContexts = query.boundedContexts()
  .withRole('Core')
  .toArray();

console.log(coreContexts[0].name); // 'OrderContext'

Load from File (Node.js)

import { loadModel } from '@domainlang/language/sdk/loader-node';

const { model, query } = await loadModel('./my-model.dlang');

// Access domains
for (const domain of query.domains()) {
  console.log(`${domain.name}: ${domain.vision}`);
}

API Overview

Entry Points

| Function | Environment | Use Case | | -------- | ----------- | -------- | | loadModelFromText(text) | Browser & Node | Parse inline DSL text | | loadModel(file) | Node.js only | Load from file system | | fromDocument(doc) | LSP integration | Zero-copy from Langium document | | fromModel(model) | Advanced | Direct AST wrapping |

Query Builder

The SDK provides fluent query builders with lazy evaluation:

// Find all bounded contexts owned by a team
const teamContexts = query.boundedContexts()
  .withTeam('PaymentsTeam')
  .toArray();

// Get context maps containing specific contexts
const maps = query.contextMaps()
  .containing('OrderContext')
  .toArray();

Direct Property Access

// Direct AST properties
const desc = boundedContext.description;
const vision = domain.vision;

// SDK-augmented properties (with precedence resolution)
const role = boundedContext.effectiveRole;  // Header 'as' wins over body 'role:'
const team = boundedContext.effectiveTeam;  // Header 'by' wins over body 'team:'

DomainLang Syntax

DomainLang models Domain-Driven Design concepts:

// Define domains with vision
Domain Sales {
  vision: "Drive revenue through great customer experience"
}

// Bounded contexts with ownership
bc OrderContext for Sales as Core by SalesTeam {
  description: "Order lifecycle management"
}

bc PaymentContext for Sales as Supporting by PaymentsTeam

// Context maps showing integrations
ContextMap SalesIntegration {
  contains OrderContext, PaymentContext
  
  [OHS,PL] OrderContext -> [CF] PaymentContext
}

Package Structure

| Path | Purpose | | ---- | ------- | | src/domain-lang.langium | Grammar definition | | src/generated/ | Auto-generated AST (do not edit) | | src/validation/ | Semantic validation rules | | src/lsp/ | LSP features (hover, completion, formatting) | | src/sdk/ | Model Query SDK |

Related Packages

• @domainlang/cli - Command-line interface
• DomainLang VS Code Extension - IDE support

Documentation

• Getting Started
• Language Reference
• Quick Reference
• SDK Documentation

Development

From the workspace root (dsl/domain-lang/):

# After editing the grammar
npm run langium:generate

# Build this package
npm run build --workspace packages/language

# Run tests
npm test --workspace packages/language

License

Apache-2.0