protean is a library for representing hierarchical data in a uniform way across multiple platforms.

The library defines a variant object that can hold primitive data as well as collections (e.g. lists, dictionaries) with arbitrary depth. The variant can be inspected, enumerated, and/or serialised to XML/binary format.

Protean has implementations in C++, C# and Python.

Protean is known to build on:

• Windows with MS Visual Studio 2013, 2015, 2017
• Mac with scons 3.0.1 and LLVM 9.0.0
• RHEL Linux with GCC 4.8.5

On Windows, the following method will work:

• Install Boost. (Known to work with 1.55 and 1.66.)
• Install Xerces. (Known to work with version 3.1.1.)
• Copy projects/vc1x/vc1x-paths.props.template to projects/vc1x/vc1x-paths.props. Edit the latter to set BOOST_VERSION, BOOST_ROOT, and XERCES_ROOT appropriately.
• Open projects/vc1x-protean.sln in your chosen version of Visual Studio.
• Choose a configuration, e.g. vc141 Release and x64, and Build Solution.

On other platforms:

• Install boost, xerces and scons dependencies, e.g. via yum or apt-get.
• Build via scons.
• If you wish to provide alternate include or lib paths, set CPPPATH or LIBPATH env vars respectively. You can also override the Boost version, via BOOST_VERSION.

using variant = protean::variant;
variant root(variant::Dictionary);
variant books(variant::Dictionary);
variant book(variant::Dictionary);
variant book_attrs(variant::Dictionary);
book_attrs.insert("author", variant("XYZ"));
book_attrs.insert("year", variant(2013));
book.insert(protean::xml_attributes, book_attrs);
book.insert(protean::xml_text, variant("some text"));
books.insert("book", book);
root.insert("books", books);
std::stringstream contents;
protean::xml_writer writer(contents, xml_mode::Preserve | xml_mode::Indent);
writer << root;
std::cout << contents.str() << std::endl;

This will output:

<?xml version="1.0" encoding="utf-8"?>
<books>
  <book author="XYZ" year="2013">some text</book>
</books>

We welcome contributions and feedback. Please make use of GitHub's issue tracking and pull requests.