subflow with taps

// ============================================================================
// Test: Taps on Subflows
// Feature: Taps should fire when subflows transition through branches
// Verifies: inline tap emission works for subflow continuations
// ============================================================================

~import "$std/taps"

const std = @import("std");

// Base event: adds 5 to a number
~event add_five { value: i32 }
| result { sum: i32 }

~proc add_five {
    std.debug.print("add_five: {} + 5 = {}\n", .{value, value + 5});
    return .{ .result = .{ .sum = value + 5 } };
}

// Subflow that calls add_five
~event double { value: i32 }
| result { doubled: i32 }

~double = add_five(value: value)
| result r |> result { doubled: r.sum }

// Observer that should be called by the tap
~event observer {}
| done {}

~proc observer {
    std.debug.print("TAP FIRED: add_five -> result transition observed!\n", .{});
    return .{ .done = .{} };
}

// Print final result
~event print_final { value: i32 }
| done {}

~proc print_final {
    std.debug.print("Final: {}\n", .{value});
    return .{ .done = .{} };
}

// TAP: Observe add_five -> result transitions
// This tap should fire when the subflow transitions through add_five's result branch
~tap(add_five -> *)
| result |> observer()
    | done |> _

// Execute the subflow - tap should fire
~double(value: 10)
| result r |> print_final(value: r.doubled)
    | done |> _