002 explicit plus catchall

// Test 918b: Optional Branches - Mix Explicit Handling + |? Catch-All
//
// Verifies:
// 1. Handler explicitly handles SOME optional branches
// 2. |? catches remaining optional branches
// 3. Most realistic real-world pattern

~import "$std/io"

// Event with required + multiple optional branches
~event process { value: u32 }
| success { result: u32 }        // REQUIRED
| ?warning { msg: []const u8 }   // OPTIONAL: handled explicitly
| ?debug { info: []const u8 }    // OPTIONAL: caught by |?
| ?trace { details: []const u8 } // OPTIONAL: caught by |?

~proc process {
    if (value > 100) {
        return .{ .warning = .{ .msg = "Value too large" } };
    }
    if (value % 2 == 1) {
        return .{ .debug = .{ .info = "Value is odd" } };
    }
    if (value < 5) {
        return .{ .trace = .{ .details = "Very small value" } };
    }
    return .{ .success = .{ .result = value * 2 } };
}

// value=10 → success (required, handled)
~process(value: 10)
| success _ |> std.io:print.ln("SUCCESS")
| warning _ |> std.io:print.ln("WARNING")
|? |> std.io:print.ln("OPTIONAL CAUGHT")

// value=150 → warning (optional, handled explicitly)
~process(value: 150)
| success _ |> std.io:print.ln("SUCCESS")
| warning _ |> std.io:print.ln("WARNING")
|? |> std.io:print.ln("OPTIONAL CAUGHT")

// value=7 → debug (optional, caught by |?)
~process(value: 7)
| success _ |> std.io:print.ln("SUCCESS")
| warning _ |> std.io:print.ln("WARNING")
|? |> std.io:print.ln("OPTIONAL CAUGHT")

// value=2 → trace (optional, caught by |?)
~process(value: 2)
| success _ |> std.io:print.ln("SUCCESS")
| warning _ |> std.io:print.ln("WARNING")
|? |> std.io:print.ln("OPTIONAL CAUGHT")