Specta Swift

[jamiepine]

Add Specta Swift - Rust to Swift Type Exporter

What's Added

This PR introduces specta-swift, a new exporter for the Specta ecosystem that generates Swift code from Rust type definitions.

Key Features

• Swift Code Generation: Converts Rust structs and enums to idiomatic Swift
• Complex Enum Support: Handles Rust enums with named fields, generating separate Swift structs
• Duration Mapping: Automatically maps std::time::Duration to a custom RustDuration helper struct
• Custom Codable: Generates proper Swift Codable implementations for complex enums
• Configurable Output: Support for different naming conventions, indentation styles, and optional syntax

Implementation

• Builder API: Fluent configuration with methods like .naming(), .indent(), .add_protocol()
• Type Mapping: Comprehensive mapping from Rust primitives to Swift equivalents
• Struct Naming: Enum variants with named fields get prefixed struct names (e.g., UserRole → UserRoleUserData)
• Documentation: Preserves Rust doc comments in generated Swift code

Testing & Examples

• 12 test files covering basic types, complex unions, string enums, and edge cases
• 8 example files demonstrating all configuration options
• 23+ generated Swift files showing actual output

Usage

use specta::{Type, TypeCollection};
use specta_swift::Swift;

#[derive(Type)]
struct User {
    id: u32,
    name: String,
    email: Option<String>,
}

fn main() {
    let types = TypeCollection::default().register::<User>();
    
    Swift::new()
        .naming(NamingConvention::CamelCase)
        .with_serde()
        .export_to("./Types.swift", &types)
        .unwrap();
}

Generates:

import Foundation
import Codable

public struct User: Codable {
    public let id: UInt32
    public let name: String
    public let email: String?
}

Files Added

• specta-swift/ - Main crate with Swift code generation
• specta-swift/src/ - Core implementation (lib.rs, swift.rs, primitives.rs, error.rs)
• specta-swift/examples/ - 8 comprehensive examples
• specta-swift/tests/ - 12 test files
• specta-swift/README.md - Documentation and usage guide

This completes the Swift exporter for the Specta ecosystem, providing a robust way to share types between Rust backends and Swift/iOS applications.

[Brendonovich]

what the sigma