So far I've been an enthusiastic user of ANTLR3, mostly for the MySQL Workbench product, where I based all the parsing infrastructure on the ANTLR3 C runtime. However, with the appearence of v4 a few years ago this ANTLR version got outdated and the support for it decreased constantly since then. Even though I would like to do so, I could not upgrade to the latest version because it missed an important piece: a C or C++ backend. Since I work mostly in a C++/Obj-C environment, this is an absolutely necessary part.
There were quite a number of requests for a C++ backend in the past and so a few attempts were made to create one. Sam Harwell, co-author of ANTLR and creator of the C# runtime started a C++ backend (utilizing C++14), but could never finish it. Dan McLaughlin and David Sisson then began porting the Java runtime to C++ about 3 years ago. However, this project also got only occasional love after the initial machine translation and had no contributions since summer 2015.
This is why I decided in March to jump in and get this thing done. You can see all the work in the fork hosted by Dan on Github.