Spirit doesn't bother me, although it's a glaring exception I did not think of to my above response. Its use of operator overloading doesn't bother me because that's the whole point of the library; you know what you're getting into ahead of time. It let me write EBNF code directly in C++: https://github.com/scotts/cellgen/blob/master/src/cellgen_gr...

The Spirit code is unlikely to be mixed in with other code. Or, put another way, I was never bothered by your complaint, because I always read it as EBNF notation first.

My real problem with Spirit was performance. It took three minutes to compile a 7000 line C++ program - more with optimizations turned on. The binary with debugging information turned on was 24 MB. And the enormous amount of copying it performed at runtime meant parsing 300 line files took a few seconds. (Luckily the runtime performance of my compiler was never important.) The new version may have fixed these problems.