[mappu]

The dynamic class is a cool idea, i'm glad it's faster for their use case, and it's nice to have canonical implementations of format and json_parse. Aside from that, seems pretty unnoteworthy - Does this fit into HipHop, or do Facebook have another large C++ project?

[ramisayar]

This all fits into Folly: The Facebook Open Source Library. https://github.com/facebook/folly