001 basic intercept

// Test 365_001: Basic Interceptor Syntax
//
// Demonstrates basic interceptor that transforms payload before delivery.
// Interceptors use ~intercept(* -> destination) to modify in-flight payloads.

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

// Target event that will be intercepted
~event log.write { logline: []const u8 }
| written {}

~proc log.write {
    std.debug.print("{s}\n", .{logline});
    return .{ .written = .{} };
}

// Interceptor: Add prefix to all log writes
~intercept(* -> log.write)
| payload p |> payload { logline: "[INTERCEPTED] " ++ p.logline }

// Test flow - the interceptor should modify the logline
~log.write(logline: "Hello World")
| written _ |> _