Modules

Modules can contain classes, enabling organized domain-driven code structures.

# models.sl

# Private helper class (not exported)
class ValidationResult
    is_valid: Bool;
    errors: String[];

    new
        this.is_valid = true;
        this.errors = [];
    end

    def add_error(msg: String)
        this.is_valid = false;
        this.errors.push(msg);
    end
end

# Exported classes
export class User
    id: Int;
    username: String;
    email: String;

    new(id: Int, username: String, email: String)
        this.id = id;
        this.username = username;
        this.email = email;
    end

    def get_display_name -> String
        this.username + " (" + this.email + ")"
    end
end

export class Post
    id: Int;
    title: String;
    content: String;
    author: User;

    new(id: Int, title: String, content: String, author: User)
        this.id = id;
        this.title = title;
        this.content = content;
        this.author = author;
    end

    def get_summary -> String
        let preview = this.content.slice(0, 100);
        this.title + " by " + this.author.username
    end
end

Modules can also contain nested classes using the :: pattern for domain organization.

# controllers.sl

export class Posts
    class Action
        def create(title: String, content: String) -> Post
            # Create a new post
            new Post(0, title, content, current_user())
        end

        def update(id: Int, updates: Any) -> Post?
            # Update an existing post
            find_post_by_id(id).update(updates)
        end

        def delete(id: Int) -> Bool
            # Delete a post
            remove_post(id)
        end
    end

    class View
        def list(page: Int, per_page: Int) -> Post[]
            paginated_posts(page, per_page)
        end

        def show(id: Int) -> Post?
            find_post_by_id(id)
        end
    end
end

export class Users
    class Action
        def register(username: String, email: String) -> User
            new User(0, username, email)
        end

        def login(email: String, password: String) -> User?
            authenticate_user(email, password)
        end
    end

    class Validator
        def validate_registration(data: Any) -> Bool
            data["username"] != null && data["email"] != null
        end
    end
end

Import classes from modules using named imports or module namespace.

# Import classes by name
import { User, Post } from "./models.sl";

let user = new User(1, "alice", "[email protected]");
let post = new Post(1, "Hello World", "Content here", user);

# Import with namespace
import "./controllers.sl" as controllers;

let action = new controllers.Posts.Action();
action.create("My Post", "Post content");

# Import nested classes directly
import { Posts::Action, Posts::View } from "./controllers.sl";

let view = new Posts::View();
let posts = view.list(1, 10);