For what it's worth at this late stage: Yes, this is an accurate summary. re2c works when it works, and there's clearly a good niche for "pattern matching stuf

For what it's worth at this late stage: Yes, this is an accurate summary. re2c works when it works, and there's clearly a good niche for "pattern matching stuff that determinizes cleanly". However, in the general case, DFAs catch fire (combinatorial explosion in # of states), especially when handling multiple regular expressions. IIRC SpamAssassin has lots of quite hard patterns and re2c can only handle a subset. I forget what the fallback position is (libpcre?).