Coding Styles

日本語

UIng offers two equivalent ways to construct an interface. Both styles use the same controls and may be mixed in one application.

Regular API

The regular API is explicit and familiar. This guide mostly uses this form.

window = UIng::Window.new("Hello", 300, 200)
window.child = UIng::Label.new("Hello from UIng")

Block-based DSL

The block-based DSL keeps nested layouts visually close to their resulting control hierarchy:

UIng::Window.new("Hello", 300, 200) {
  child { UIng::Label.new("Hello from UIng") }
}

Here is an example with a deeper nesting:

UIng.init do
  UIng::Window.new("Hello World", 300, 200) { |win|
    on_closing { UIng.quit; true }
    child {
      UIng::Button.new("Click me") {
        on_clicked {
          win.msg_box("Info", "Button clicked!")
        }
      }
    }
    show
  }

  UIng.main
end

The DSL is implemented with Crystal's with ... yield syntax. Inside a block, methods are called with the control instance as self, so instead of assignments like window.child = ... you can write child { ... }.

Which to choose

• Regular API: suits simple structures and code where you want the flow to be explicit.
• DSL: suits deeply nested layouts that read best when written close to their hierarchy.

Both styles create the same controls. Either choice is fine as long as the project stays consistent.