Swift-Powered Site Generation

When most people think of Swift, they think of iOS apps. But Swift is a powerful, general-purpose language that excels at building developer tools, CLI applications, and—as fddl demonstrates—static site generators.

Why Swift for a Static Site Generator?

1. Blazing Performance

Swift is a compiled language with performance comparable to C++. For a static site generator that might process thousands of markdown files, this matters. While the difference might be negligible for a small blog, it becomes significant when generating large documentation sites or content-heavy projects.

// Swift's type system and compiler optimizations
// make operations like this incredibly fast
let pages = try markdownFiles.map { file in
    try processor.process(file)
}

2. Type Safety and Reliability

Swift’s strong type system catches errors at compile time, not when your users are trying to build their sites. Optional handling, type inference, and Swift’s emphasis on safety mean fewer runtime crashes and more predictable behavior.

struct Page {
    let title: String
    let content: String
    let metadata: [String: Any]?  // Optional, safely handled
}

3. Modern Language Features

Swift brings modern programming paradigms to systems-level performance:

Optionals: No more null pointer exceptions
Generics: Write reusable, type-safe code
Protocol-Oriented Programming: Flexible, composable architectures
Value Types: Safer concurrent code with structs
Error Handling: Explicit, type-safe error propagation

4. Excellent Tooling

The Swift Package Manager (SPM) makes dependency management straightforward. No separate build tools, no complex configuration—just a clean Package.swift file.

The Dependencies That Power fddl

fddl stands on the shoulders of excellent Swift packages:

ArgumentParser

Apple’s swift-argument-parser makes building CLI tools a breeze:

import ArgumentParser

struct Generate: ParsableCommand {
    @Flag(help: "Enable verbose output")
    var verbose = false

    func run() throws {
        // Your generation logic here
    }
}

Clean, declarative, and type-safe command-line interfaces with automatic help generation.

Yams

YAML parsing for frontmatter and configuration files:

import Yams

let frontmatter = try Yams.load(yaml: yamlString)

Essential for reading the metadata in markdown files and template configurations.

swift-markdown

Apple’s official markdown parser provides robust, standards-compliant markdown processing:

import Markdown

let document = Document(parsing: markdownContent)
// Process and transform the markdown AST

This gives fddl fine-grained control over markdown rendering and enables custom transformations.

Splash

Syntax highlighting for code blocks, created by John Sundell:

import Splash

let highlighter = SyntaxHighlighter(format: HTMLOutputFormat())
let html = highlighter.highlight(code)

This is what makes code examples in fddl-generated sites look beautiful.

SwiftNIO

For the development server with hot reload capabilities:

import NIOCore
import NIOHTTP1
import NIOWebSocket

// Build a high-performance HTTP server with WebSocket support

SwiftNIO provides the foundation for fddl’s dev server, enabling features like live reload and file watching.

The Architecture

fddl is organized into focused modules:

Commands: CLI command implementations
Core: Site generation engine
Markdown: Markdown processing and shortcode handling
Templates: Template rendering system
Plugins: Extensible plugin architecture
DevServer: Development server with hot reload
FileSystem: File operations and asset management

Each module has a clear responsibility, making the codebase maintainable and extensible.

Performance in Practice

Thanks to Swift’s performance characteristics, fddl can:

Generate thousands of pages in milliseconds
Process markdown with minimal overhead
Handle concurrent file operations safely
Serve development previews with low latency

The Swift Ecosystem Advantage

By choosing Swift, fddl benefits from:

Active Development: Swift continues to evolve with new features
Strong Community: Growing beyond just iOS development
Cross-Platform: Works on macOS, Linux, and (experimentally) Windows
Professional Tooling: Xcode, LSP support, excellent debugging

Is Swift Right for Your CLI Tool?

If you’re building developer tools and you value:

Compile-time safety over scripting flexibility
High performance without manual memory management
Modern language features with systems-level control
A growing ecosystem of quality packages

Then Swift might be the perfect choice.

What’s Next?

In our next post, we’ll explore fddl’s features in detail—from shortcodes and plugins to the template system and dev server.

“Swift is not just for apps. It’s for anything you want to build.” — The fddl philosophy