003 impl override only

// Test 430_003: Abstract with Override Only (No Default)
// When an abstract event has an override but NO default:
// - The override IS the handler
// - Calling `event.default()` would be a compiler error (no default exists!)
//
// This is "provide the implementation" pattern.

~import "$std/io"

// Define abstract event with NO default implementation
~[abstract] event greet { name: []const u8 }
| greeted { message: []const u8 }

// Provide the ONLY implementation (this becomes the handler)
~greet = greeted { message: name }

// Use it
~greet(name: "world")
| greeted g |> io.println(message: g.message)