Fans of the programming language D are heralding the fact that Facebook is now running some D code in live production. Developer Andrei Alexandrescu wrote the 5112 lines that are now part of Facebook's repository, and he notes that the new code is superior to the C++ code in replaced in terms of source code size, build speed and runtime performance. He added, "D has resolutely exited C++'s shade because it is good at things C++ is not good at, in addition to being good at things C++ is good at."
Another D developer, J.M. Davis noted, "It doesn't mean that D has taken over the programming world or anything like that, but it shows that the language is maturing and that real companies are now willing to use it in the real world — and it's a pretty major company at that."