I've found re2c + lemon to be a pretty good combination. re2c has good unicode support -- takes a while to compile if attempting TR31 "Unicode Identifier And P

I've found re2c + lemon to be a pretty good combination. re2c has good unicode support -- takes a while to compile if attempting TR31 "Unicode Identifier And Pattern Syntax" though. Haven't used lemon on anything too complicated, I basically just play with grammars for fun, but it works really well for my MiniScheme fork I like to poke at every once in a while. My new shiny is Coco/R which is a dream to use (once you get up the learning curve) but hasn't really been maintained for ages.