Lite::Data

Easy definition of data classes with subclassing support and flexible constructor signatures.

Overview

Closely follows the interface of Ruby 3.2's Data class, but adds:

• Subclassing capability
• Mixed positional and keyword arguments
• Module-based design for including in existing classes

Class definition

Defining a data class

Use Lite::Data.define(klass, args:, kwargs:) with arrays for positional and keyword parameters. The following declaration generates a module with necessary instance methods and includes it in the target class:

```ruby rspec definition_superclass class Foo Lite::Data.define(self, args: [:foo]) end

expect(Foo.new('FOO').foo).to eq('FOO')

The same works when extending existing data classes:
```ruby rspec definition_subclass
class Bar < Foo
  Lite::Data.define(self, kwargs: [:bar])
end

expect(Bar.new('FOO', bar: 'BAR').bar).to eq('BAR')

Argument positioning in subclasses

By default, new positional arguments are added at the start. Use :'*' as a placeholder to control positioning:

```ruby rspec definition_argument_positioning class Bax < Bar Lite::Data.define(self, args: [:'*', :bax]) end

expect(Bax.new('FOO', 'BAX', bar: 'BAR').bax).to eq('BAX')

## Generated methods
Classes automatically receive:
- **Comparison**: `==`, `eql?`, `hash`
- **Cloning**: `with`
- **Introspection**: `deconstruct`, `deconstruct_keys`, `to_h`

### Destructuring order
The `deconstruct` method returns values in order of inheritance, 
each class contributes its members in order of definition, 
positional first:
```ruby rspec introspection_deconstruct
# inheritance chain: Bax < Bar < Foo
expect(Bax.new('FOO', 'BAX', bar: 'BAR').deconstruct)
  .to eq(%w[FOO BAR BAX])

License

This library is published under MIT license