005 deep error handling

// Test 832: Deep error handling
//
// Real apps handle errors at every level.
// This tests that error branches work correctly when deeply nested.

const std = @import("std");

~event step1 {}
| ok { value: i32 }
| failed { reason: []const u8 }

~event step2 { value: i32 }
| ok { value: i32 }
| failed { reason: []const u8 }

~event step3 { value: i32 }
| ok { value: i32 }
| failed { reason: []const u8 }

~event step4 { value: i32 }
| ok { value: i32 }
| failed { reason: []const u8 }

~event log { msg: []const u8 }
| done {}

~proc step1 {
    return .{ .@"ok" = .{ .value = 1 } };
}

~proc step2 {
    if (value < 0) {
        return .{ .@"failed" = .{ .reason = "step2 failed" } };
    }
    return .{ .@"ok" = .{ .value = value + 1 } };
}

~proc step3 {
    if (value < 0) {
        return .{ .@"failed" = .{ .reason = "step3 failed" } };
    }
    return .{ .@"ok" = .{ .value = value + 1 } };
}

~proc step4 {
    if (value < 0) {
        return .{ .@"failed" = .{ .reason = "step4 failed" } };
    }
    return .{ .@"ok" = .{ .value = value + 1 } };
}

~proc log {
    std.debug.print("{s}\n", .{msg});
    return .{ .@"done" = .{} };
}

// 4 levels deep with error handling at each level
~step1()
| ok s1 |> step2(value: s1.value)
    | ok s2 |> step3(value: s2.value)
        | ok s3 |> step4(value: s3.value)
            | ok _ |> log(msg: "Success!")
                | done |> _
            | failed f |> log(msg: f.reason)
                | done |> _
        | failed f |> log(msg: f.reason)
            | done |> _
    | failed f |> log(msg: f.reason)
        | done |> _
| failed f |> log(msg: f.reason)
    | done |> _