Alternative libraries

Why this library? Because none of the existing libraries was quite what I wanted. When I started this project in 2018, I was aware of these two alternative C/C++ libraries:

• libyaml. This is a bare C library. It does not create a representation of the data tree, so I don’t see it as practical. My initial idea was to wrap parsing and emitting around libyaml’s convenient event handling, but to my surprise I found out it makes heavy use of allocations and string duplications when parsing. I briefly pondered on sending PRs to reduce these allocation needs, but not having a permanent tree to store the parsed data was too much of a downside.

• yaml-cpp. This library may be full of functionality, but is heavy on the use of node-pointer-based structures like std::map, allocations, string copies, polymorphism and slow C++ stream serializations. This is generally a sure way of making your code slower, and strong evidence of this can be seen in the benchmark results above.

Recently libfyaml appeared. This is a newer C library, fully conformant to the YAML standard with an amazing 100% success in the test suite; it also offers the tree as a data structure. As a downside, it does not work in Windows, and it is also multiple times slower parsing and emitting.

When performance and low latency are important, using contiguous structures for better cache behavior and to prevent the library from trampling caches, parsing in place and using non-owning strings is of central importance. Hence this Rapid YAML library which, with minimal compromise, bridges the gap from efficiency to usability. This library takes inspiration from RapidJSON and RapidXML.