I have to develop a parser/compiler for First Order Logic (FOL) clauses in C/C++ language. I have made a lot of search on the web but I have found only a source codes written in ML, PROLOG, Haskell, Phyton, etc. I'm studying Flex and Bison to understand how I can generate a parser. I think it's a big work for me. Do you know if exist an open source implementation (C/C++) from which I can start?