improve compilation performance of the alt! parser
improve compilation performance of the alt! parser

meh/nom,pwoolcoc/nom,sourrust/nom,ngrewe/nom,colinsurprenant/nom,alan-andrade/nom,AndyShiue/nom,nox/nom,daboross/nom,Keruspe/nom,badboy/nom,tempbottle/nom,Geal/nom,ahenry/nom,frewsxcv/nom,bluss/nom,rillian/nom