fnparse recursive?

[aboytsov]

Hey, guys,

We're using fnparse in Drake, and we're running into some parsing performance and stack issues. Parsing a 15k line source of a very simple structure takes forever (minutes) and fails with stack overflow. I tried to profile it with YourKit Java Profiler, and I'm getting endless stack traces full of monads' m_bind_state_t and m_bind_maybe:

The list of most expensive methods by self-time.

It might be that we're doing something wrong defining grammar. Just in case you want to look at it, it's defined here and here.

We used the JSON parser example as a base, and we use a similar method for updating the current column/line numbers. One observation is that getting rid of column/line tracking reduces parsing time of ~500 line file from 4s to <2s or so. Just that simple change.

We're looking for any advice on how to bring parsing times under control, and also if there's a more efficient method for updating column/line than used in your example.

Thank you!