Generate Swift code programmatically with declarative syntax

1 hour ago 2

Generate Swift code programmatically with declarative syntax. SyntaxKit is a Swift package that provides a type-safe, result builder-based API for generating Swift code structures. It's designed for macro development, model transformers, and migration utilities—scenarios where you need to programmatically create Swift code rather than writing it by hand.

Unlike manually writing SwiftSyntax AST nodes, SyntaxKit uses result builders to make code generation readable and maintainable. Perfect for macro authors who need to generate complex Swift structures, or developers building tools that automatically create boilerplate code from external schemas, APIs, or configurations.

When to Use SyntaxKit
Installation
Quick Start
Why SyntaxKit Excels
Features
Documentation
Contributing
Requirements
License

graph TD A[Need to generate Swift code?] --> B{Code generation frequency?} B -->|One-time/Static| C[Write Swift manually] B -->|Repetitive/Dynamic| D{What type of generation?} D -->|Swift Macros| E[✅ Perfect for SyntaxKit] D -->|Data Model Generation| F[✅ Ideal SyntaxKit use case] D -->|Model/Entity Generation| G[✅ Great SyntaxKit fit] D -->|Developer Tools| H[✅ SyntaxKit recommended] D -->|App Logic/UI| I[❌ Use regular Swift] style E fill:#22c55e,stroke:#16a34a,color:#ffffff style F fill:#22c55e,stroke:#16a34a,color:#ffffff style G fill:#22c55e,stroke:#16a34a,color:#ffffff style H fill:#22c55e,stroke:#16a34a,color:#ffffff style I fill:#ef4444,stroke:#dc2626,color:#ffffff style C fill:#6b7280,stroke:#4b5563,color:#ffffff

✅ Choose SyntaxKit when:

Building Swift macros or compiler plugins
Generating Swift code from external schemas (GraphQL, databases, JSON schemas)
Creating developer tools that output Swift code
Building code generators or transformers
Need type-safe programmatic Swift code construction

❌ Use regular Swift when:

Writing application business logic
Creating UI components or view controllers
Building standard iOS/macOS app features
Code you'd write once and maintain manually

🎓 New to SyntaxKit? Start with our Complete Getting Started Guide - from zero to building your first macro in 10 minutes.

Add SyntaxKit to your project using Swift Package Manager:

// Package.swift dependencies: [ .package(url: "https://github.com/brightdigit/SyntaxKit.git", from: "0.0.3") ]

1. Create Your First Code Generator (2 minutes)

import SyntaxKit // Generate a data model with Equatable conformance let userModel = Struct("User") { Variable(.let, name: "id", type: "UUID") Variable(.let, name: "name", type: "String") Variable(.let, name: "email", type: "String") } .inherits("Equatable") print(userModel.generateCode())

2. See the Generated Result (instant)

struct User: Equatable { let id: UUID let name: String let email: String }

3. Build a Simple Macro (2 minutes)

import SyntaxKit import SwiftSyntaxMacros @main struct StringifyMacro: ExpressionMacro { static func expansion( of node: some FreestandingMacroExpansionSyntax, in context: some MacroExpansionContext ) throws -> ExprSyntax { // Get the first argument from the macro call guard let argument = node.arguments.first?.expression else { return Literal.string("").syntax.as(ExprSyntax.self)! } // Use SyntaxKit to generate a string literal from the argument let sourceCode = argument.trimmed.description let stringLiteral = Literal.string(sourceCode) return stringLiteral.syntax.as(ExprSyntax.self)! } }

✅ Done! You've built type-safe Swift code generation. Ready for complex scenarios like API client generation or model transformers.

Basic Code Generation Example

SyntaxKit provides a set of result builders that allow you to create Swift code structures in a declarative way. Here's an example:

import SyntaxKit let code = Struct("BlackjackCard") { Enum("Suit") { EnumCase("spades").equals("♠") EnumCase("hearts").equals("♡") EnumCase("diamonds").equals("♢") EnumCase("clubs").equals("♣") } .inherits("Character") } let generatedCode = code.generateCode()

This will generate the following Swift code:

struct BlackjackCard { // nested Suit enumeration enum Suit: Character { case spades = "♠" case hearts = "♡" case diamonds = "♢" case clubs = "♣" } }

Create structs, enums, and cases using result builders
Add inheritance and comments to your code structures
Generate formatted Swift code using SwiftSyntax
Type-safe code generation
Comprehensive support for Swift language features

📚 Complete Documentation Portal

🚀 Getting Started Guide - Your first SyntaxKit project in 10 minutes
🔧 Macro Development Tutorial - Complete macro creation walkthrough

GitHub Issues - Bug reports and feature requests
GitHub Discussions - Community questions and showcases

We welcome contributions to SyntaxKit! Whether you're fixing bugs, adding features, or improving documentation, your help makes SyntaxKit better for everyone.

📝 Documentation Contributions

Documentation Contribution Guide - Standards and review process for documentation changes
Review checklist for tutorials, articles, and API documentation
Guidelines for writing clear, tested examples

# Clone and set up the project git clone https://github.com/brightdigit/SyntaxKit.git cd SyntaxKit # Run quality checks ./Scripts/lint.sh # Build and test swift build swift test

Check existing issues and discussions to avoid duplicates
For documentation changes, follow CONTRIBUTING-DOCS.md guidelines
Ensure all tests pass and code follows project standards
Consider adding tests for new functionality

Swift 6.0+

This project is licensed under the MIT License - see the LICENSE file for details.

🔗 For OpenAPI code generation: Check out the official Swift OpenAPI Generator for generating Swift code from OpenAPI specifications.

Read Entire Article

Generate Swift code programmatically with declarative syntax

1. Create Your First Code Generator (2 minutes)

2. See the Generated Result (instant)

3. Build a Simple Macro (2 minutes)

Basic Code Generation Example

📚 Complete Documentation Portal

📝 Documentation Contributions

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