Dia

import ui.{View, run, Column, Text, Button, state}

@observable
struct CounterState {
  value: i32
}

fn Counter(): View !{alloc} {
  let s = state(CounterState{ value: 0 })

  <Column spacing=12>
    <Text>"Count: ${s.value}"</Text>
    <Button
      label="Increment"
      on_click=() => { s.value += 1 }
    />
  </Column>
}

pub fn main(): void !{alloc, io} {
  run(() => <Counter />)
}

extern "C" import "raylib.h" as rl

pub fn main(): void !{io, alloc} {
  rl.InitWindow(800, 600, "Hello from Dia")
  defer rl.CloseWindow()

  rl.SetTargetFPS(60)

  while !rl.WindowShouldClose() {
    rl.BeginDrawing()
    rl.ClearBackground(rl.RAYWHITE)
    rl.DrawText(
      "A C library, called from Dia.",
      40, 40, 24, rl.BLACK
    )
    rl.EndDrawing()
  }
}

struct Note {
  title: String
}

fn rename(mut note: Note): void {
  note.title = "Revised"
}

fn is_draft(note: Note): bool => note.title == "First draft"

pub fn main(): void !{alloc} {
  let original = Note{ title: "First draft" }
  var draft = copy original  // independent copy

  rename(mut draft)         // borrow to mutate
  let unchanged = is_draft(original) // borrow to read

  let saved = take draft    // transfer ownership
  // draft can no longer be used here.
  // original still contains "First draft".
  // Owned values are dropped at scope exit.
}