regexp2go author here: yes, mostly it's the combination of the regexp package not aiming at top performance and therefore omitting some optimizations, the impli

regexp2go author here: yes, mostly it's the combination of the regexp package not aiming at top performance and therefore omitting some optimizations, the implicit regexp interpreter overhead, and the go compiler not aiming at top performance. On the avoiding exponential slowdown front, regexp2go and other re2-inspired implementations (including e.g. rust's) all have that as a goal.