ComponentProperty

open class SomeComponent {
     val myProp = ComponentProperty("some text")
     val myBooleanProp = ComponentProperty(false)

     // should rather be some implementation in the default theme of course!
     class SizesContext {
         small: Style<BasicParams> = { fontSize { small } }
         normal: Style<BasicParams> = { fontSize { small } }
         large: Style<BasicParams> = { fontSize { small } }
     }

     val sizes = ComponentProperty<SizesContext.() -> Style<BasicParams>> { normal }
}
// within your UI declaration:
someComponent {
     myProp("Some specific content") // pass simple parameter
     myBooleanProp(true)
     sizes { large } // use expression syntax
}