Still, it shouldn't be that bad. Most of what A5 calls for that's new is needed for Parrot's parser anyway, so there's a serious overlap there, which means we can do it all just once and save some time and effort.

Perl 6's regexes may be slow, but I'm not sure that'll really happen. One thing that will help is the JIT, which will reduce some of the time eaten up by bandwidth issues. The single biggest time sink with making these Parrot opcodes is that everything involved with parrot opcodes is 32 bit, while perl 5's regex bytecode engine is all 8-bit. (And yes, the perl 5 regex engine is a bytecode engine too) That means wer're moving four times as much data across the processor bus. OTOH, it's naturally aligned, which helps, and if things stay in L1 cache it's not a problem anyway. It's the initial cache load, and the times when things spill out of L1 cache, that really hurt.

There's a fair amount we can do about that, and I'm more than happy to put in as much cheating as we need to for speed reasons. (At the moment, the single biggest reason that perl 5's regex engine is faster than a comparable one in Parrot is that perl 5's regex engine does a lot of optimization of the search, which'll make a huge difference)