Summary
Consolidate 9 Result related header files into 3 logical groups, preparing for C++20 module migration while following Kent Beck's "Fewest Elements" principle.
Current State
Directory: include/kcenon/common/patterns/
File Inventory (9 files)
patterns/
├── result.h # Umbrella header (includes all below)
├── result_helpers.h # Additional helpers
└── result/
├── fwd.h # Forward declarations
├── error_info.h # error_info struct
├── result_core.h # Result<T> class
├── optional.h # Optional utilities
├── result_funcs.h # Factory functions (ok, err)
├── error_codes_compat.h # Legacy error code support
├── exception_conversion.h # Exception utilities
└── result_macros.h # Convenience macros
Current result.h (umbrella)
#pragma once
#include "result/fwd.h"
#include "result/error_info.h"
#include "result/result_core.h"
#include "result/optional.h"
#include "result/result_funcs.h"
#include "result/error_codes_compat.h"
#include "result/exception_conversion.h"
#include "result/result_macros.h"
Problem Analysis
| Issue |
Impact |
| 9 files for 1 concept |
Complex include dependencies |
| Unclear which header to include |
User confusion |
| Module boundary unclear |
C++20 migration difficulty |
| Compile-time overhead |
9 file opens per include |
Kent Beck Principles
- Fewest Elements: 9 files → 3 files
- Reveals Intention: Unclear separation of concerns
C++20 Module Impact
When converting to modules, need clear partitions:
export module kcenon.common.result; // Primary
export module kcenon.common.result:core; // Partition
export module kcenon.common.result:utils; // Partition
Proposed Solution: 3 Logical Groups
New Structure
patterns/
├── result.h # Umbrella (unchanged, backward compat)
└── result/
├── core.h # Combined: fwd + error_info + result_core + optional
├── utilities.h # Combined: result_funcs + exception_conversion + macros
└── compat.h # Legacy: error_codes_compat
core.h Contents
#pragma once
#include <optional>
#include <string>
#include <variant>
#include <kcenon/common/utils/source_location.h>
namespace kcenon::common {
// Forward declarations (from fwd.h)
template<typename T> class Result;
using VoidResult = Result<void>;
// Error info (from error_info.h)
struct error_info {
int code;
std::string message;
std::string module;
std::optional<std::string> details;
// ... rest of implementation
};
// Result class (from result_core.h)
template<typename T>
class Result {
// ... full implementation
};
// Optional utilities (from optional.h)
// ... if needed
} // namespace kcenon::commonutilities.h Contents
#pragma once
#include "core.h"
namespace kcenon::common {
// Factory functions (from result_funcs.h)
template<typename T>
Result<T> make_ok(T&& value);
template<typename T>
Result<T> make_err(error_info error);
// Exception conversion (from exception_conversion.h)
template<typename T, typename F>
Result<T> try_catch(F&& func);
// Macros (from result_macros.h)
#define KCENON_TRY(expr) ...
#define KCENON_UNWRAP(expr) ...
} // namespace kcenon::commoncompat.h Contents
#pragma once
#include "core.h"
namespace kcenon::common {
// Legacy error codes (from error_codes_compat.h)
// For backward compatibility with older error handling
[[deprecated("Use error_info directly")]]
enum class error_code { ... };
} // namespace kcenon::commonMigration Path
Phase 1: Create new consolidated headers
- Create
core.h, utilities.h, compat.h
- Copy content from individual files
Phase 2: Update umbrella header
// result.h - maintains backward compatibility
#pragma once
// New consolidated headers
#include "result/core.h"
#include "result/utilities.h"
#include "result/compat.h" // Optional, for legacy support
Phase 3: Deprecate individual headers
// result/fwd.h
#pragma once
#pragma message("result/fwd.h is deprecated. Use result/core.h")
#include "core.h"Phase 4: Remove deprecated (next major version)
- Remove individual files
- Update documentation
Tasks
Acceptance Criteria
C++20 Module Ready Structure
// Future module structure
export module kcenon.common.result;
export import :core; // Primary types
export import :utilities; // Factory functions
// :compat is internal only
Metrics
| Metric |
Before |
After |
| Header files |
9 |
3 (+1 umbrella) |
| Include depth |
8 |
2 |
| Module partitions |
unclear |
3 clear |
Related
- C++20 Module Migration Epic
- Kent Beck "Fewest Elements" principle
Summary
Consolidate 9 Result related header files into 3 logical groups, preparing for C++20 module migration while following Kent Beck's "Fewest Elements" principle.
Current State
Directory:
include/kcenon/common/patterns/File Inventory (9 files)
Current result.h (umbrella)
Problem Analysis
Kent Beck Principles
C++20 Module Impact
When converting to modules, need clear partitions:
Proposed Solution: 3 Logical Groups
New Structure
core.h Contents
utilities.h Contents
compat.h Contents
Migration Path
Phase 1: Create new consolidated headers
core.h,utilities.h,compat.hPhase 2: Update umbrella header
Phase 3: Deprecate individual headers
Phase 4: Remove deprecated (next major version)
Tasks
result/core.hcombining fwd + error_info + result_core + optionalresult/utilities.hcombining result_funcs + exception_conversion + macrosresult/compat.hwith error_codes_compatresult.humbrella to use new headersAcceptance Criteria
C++20 Module Ready Structure
Metrics
Related