008 event pump

// Test 918h: Optional Branches - Event Pump Loop (THE USE CASE)
//
// Verifies:
// 1. Event pump with multiple optional event types
// 2. Loop using labels/jumps that repeatedly calls pump
// 3. |? catches unhandled events, loop continues
// 4. THE motivating use case: wrapping WIN32/SDL/etc event systems

~import "$std/io"

const std = @import("std");

// Simulated event pump - all branches optional (any event can fire)
~event pump { iteration: u32 }
| ?keyboard { code: i32 }
| ?mouse { code: i32 }
| ?window { code: i32 }
| ?timer { code: i32 }
| ?quit {}

~proc pump {
    const i = iteration;

    // After 8 iterations, quit
    if (i >= 8) {
        return .{ .quit = .{} };
    }

    // Cycle: keyboard, mouse, window, timer
    const event_type = i % 4;
    if (event_type == 0) {
        return .{ .keyboard = .{ .code = @intCast(i) } };
    } else if (event_type == 1) {
        return .{ .mouse = .{ .code = @intCast(i) } };
    } else if (event_type == 2) {
        return .{ .window = .{ .code = @intCast(i) } };
    } else {
        return .{ .timer = .{ .code = @intCast(i) } };
    }
}

// Event loop: only handle keyboard and mouse, |? catches the rest
~#loop pump(iteration: 0)
| keyboard _ |> std.io:print.ln("KEYBOARD") |> @loop(iteration: iteration + 1)
| mouse _ |> std.io:print.ln("MOUSE") |> @loop(iteration: iteration + 1)
| quit _ |> std.io:print.ln("QUIT")
|? |> std.io:print.ln("OTHER") |> @loop(iteration: iteration + 1)