Added rfl::Commented; resolves #597

[liuzicheng1987]

No description provided.

[gemini-code-assist]

Summary of Changes

Hello @liuzicheng1987, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request introduces a significant feature by adding the rfl::Commented<T> wrapper, which allows developers to embed descriptive comments directly within their data structures. These comments are then seamlessly serialized into formats like YAML and XML, greatly improving the readability and maintainability of the generated output. The implementation ensures that comments are handled as write-only metadata, focusing on enhancing the clarity of serialized data without affecting deserialization logic.

Highlights

• New rfl::Commented Wrapper: Introduced a new rfl::Commented<T> class template that allows associating an optional comment string with any data field T. This enhances the self-documenting capabilities of serialized data.
• YAML and XML Comment Support: The rfl::Commented wrapper is fully integrated with YAML and XML serialization, enabling comments to be written directly into the output. Comments are rendered as line comments (#) in YAML and <!-- comment --> blocks in XML.
• Write-Only Comment Functionality: Comments added via rfl::Commented are write-only; they are preserved during serialization but are intentionally ignored during deserialization, as is common practice for comments in data formats.
• Comprehensive Documentation and Testing: New documentation (docs/commented.md) has been added to explain the usage and API of rfl::Commented, complemented by dedicated unit tests for both XML and YAML serialization to ensure correct functionality.

Changelog

• README.md
  • Updated the list of custom containers to include rfl::Commented.
• docs/commented.md
  • Added new documentation for rfl::Commented, explaining its purpose, usage with YAML and XML examples, and API details.
• docs/docs-readme.md
  • Added a link to the new rfl::Commented documentation page.
• include/rfl.hpp
  • Included the new rfl/Commented.hpp header.
  • Corrected a duplicate include for rfl/CamelCaseToSnakeCase.hpp.
• include/rfl/Commented.hpp
  • New file: Defines the rfl::Commented<T> class template, which wraps a value and an optional comment, providing constructors and accessors.
• include/rfl/parsing/Parent.hpp
  • Included supports_comments.hpp.
  • Added a static add_comment method to Parent to allow writers to attach comments to array or object elements.
• include/rfl/parsing/Parser.hpp
  • Included the new Parser_commented.hpp.
• include/rfl/parsing/Parser_commented.hpp
  • New file: Implements the Parser specialization for rfl::Commented<T>, handling serialization of comments (for supported writers) and ignoring them during deserialization.
• include/rfl/parsing/supports_comments.hpp
  • New file: Defines a C++ concept supports_comments to identify writers that can handle comments.
• include/rfl/xml/Writer.hpp
  • Updated namespace declaration to rfl::xml.
  • Added declarations for add_comment_to_array and add_comment_to_object methods.
  • Minor formatting adjustment in a comment.
• include/rfl/yaml/Writer.hpp
  • Updated namespace declaration to rfl::yaml.
  • Modified parameter names for add_array_to_array and add_array_to_object to indicate unused arguments.
  • Added declarations for add_comment_to_array, add_comment_to_object, and new_comment methods.
• mkdocs.yaml
  • Updated the documentation navigation menu to include rfl::Commented.
• src/rfl/xml/Writer.cpp
  • Implemented add_comment_to_array and add_comment_to_object to append XML comment nodes.
  • Simplified Ref<pugi::xml_node>::make calls for root element creation.
• src/rfl/yaml/Writer.cpp
  • Implemented add_comment_to_array, add_comment_to_object, and new_comment methods to integrate YAML comments into the output.
• tests/xml/test_comment.cpp
  • New file: Added a unit test to verify rfl::Commented functionality with XML serialization.
• tests/yaml/test_comment.cpp
  • New file: Added a unit test to verify rfl::Commented functionality with YAML serialization.

Activity

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Code Review

This pull request introduces rfl::Commented, a useful feature for adding comments to serialized data in formats that support them, like YAML and XML. The implementation is comprehensive, covering the new type, parser specializations, and updates to the XML and YAML writers. The documentation and tests are also well-written.

I've found a few issues, mostly in the rfl::Commented class implementation regarding converting constructors and assignment operators, which could lead to data loss (comments being discarded) or compilation errors. There's also a minor issue with JSON schema generation for Commented<T> and a couple of small typos/inconsistencies. Addressing these points will improve the robustness and consistency of the new feature.