myxml

Extensible Markup Language (XML) is a markup language and file format for storing, transmitting, and reconstructing arbitrary data. It defines a set of rules for encoding documents in a format that is both human-readable and machine-readable. The World Wide Web Consortium's XML 1.0 Specification of 1998 and several other related specifications—all of them free open standards—define XML.

Learn more about XML on Wikipedia

myxml is a minimal and user-friendly XML DOM parser designed to be easy to integrate and extend.

Why myxml?

myxml is developed in modern C++(17), leveraging the capabilities of string_view, shared_ptr, optional, variant and some of newest SNIFAE utility(sadly not concept). It's fully modulized(not all in one file) and has a well-designed Is-a relationship.

Many of the most-starred XML parsers on GitHub are somewhat outdated and not as handy as popular JSON parsers like nlohmann. It’s time to create a modern alternative.

Currently myxml has only around 2000 lines of code, making it easy to get involved in its development. While it's far far from perfect, myxml is perfect for anyone looking to contribute to a modern C++ project. Share your ideas with us!

Progress and Roadmap

The repo is still a work in progress and has not yet fully support all XML features. Contributions are welcome! Read Contribution Guide for more information. Turn to issues to see what I think we should do.

What it can do now

• Parsing nested elements with text and attributes
• Entity encoding and newline normalization in text
• Parsing document with declaration and a root element
• Parsing CDATA
• Providing parsing error info

TODOs

• Support full-featured Processing Instructions
• Implement XML Namespace Parsing
• Add XPath Support
• Integrate DTD/XML Schema Validation
• Refactor for Zero-Copy Efficiency

Zero-Copy?

myxml uses XMLFile class to load files, leveraging mmap to opening files. Additionally myxml implements StringBuffer class, which holds a reference to any string used to build the DOM tree, or stores a moved string object. While myxml doesn't copy the entire data of an XMLDocument, it does copy Text and CDATA instead of referencing the source data. This is based on the assumption that user may drop raw string or close file after parsing, which may lead to dangling reference. Maybe myxml can offer an option for users who explicitly require zero-copy implementation in the future.

Setup

Dependencies

myxml uses git submodule to manage dependencies. Run following commands first:

git submodule init
git submodule update

Compilation

Ensure that your environment meets the following requirements:

• CMake version > 3.22
• C++ compiler with C++17 support

To compile the project, navigate to the project directory and run:

cmake -S . -B build
cmake --build build

If you don't want to compile testing, add -DBUILD_TESING=OFF to the configure command.

Running tests

In the project directory, run:

ctest --test-dir build/tests/

Installation

In the project directory, run:

cmake --install build # usually requires root permission

Then your C++ Compiler will be able to find myxml directly.

Integration

If you want to integrate myxml into your CMake project, add this repo to your project and modify your root CMakeLists.txt:

add_subdirectory(myxml)  # or `deps/myxml`, as you like

Linking myxml to any target that requires it:

target_link_libraries(your_target PRIVATE myxml)

Usage

Here’s a basic example:

#include <myxml/element.hpp>

int main()
{
    auto elem = myxml::element::parse("<root attr=\"value\">Hello, world!<root/>");
    std::cout << elem.first_text() << std::endl;    // "Hello, world!";
    std::cout << elem["attr"] << std::endl;      // "value"
}

Create Element using custom string literal:

#include <myxml/element.hpp>
// enable literals by using namespace
using namespace xml::literals;

int main()
{
    auto elem = "<root></root>"_elem;
    std::cout << elem.name() << std::endl; // root
}

Similar Approach for myxml::document.

Parse file:

#include <myxml/document.hpp>

int main()
{
    auto doc = myxml::document::load("filename");
    auto root = doc.root();
}

For more examples, read examples and test files here.

Code Coverage

myxml support code coverage analysis via Codecov. Install Codecov browser extension to visualize which lines of code are covered and which are not.

Inspiration

This repo is inspired by tinyxml2, pugixml and nlohmann/json.