040 tap as library

// Test: Taps implemented as a library transform
// This proves taps don't need special syntax - they're just metaprogramming!

const std = @import("std");
~import "$std/taps"

// An event with a branch that can be tapped
// NOTE: Taps work by observing TRANSITIONS (branches), not void events!
// The branch is named 'tap_target' to make clear this is TEST SCAFFOLDING.
~event hello {}
| tap_target {}

~proc hello {
    std.debug.print("Hello executed\n", .{});
    return .{ .tap_target = .{} };
}

// A void observer event - no return needed
~event observer {}

~proc observer {
    std.debug.print("Observer fired!\n", .{});
}

// TAP: Observe hello -> * | tap_target
// Using the new library syntax instead of special ~hello -> * syntax
~tap(hello -> *)
| tap_target |> observer()

// Execute hello - tap should fire on tap_target branch
~hello()
| tap_target |> _