Pharo uses (right now) RBParser as the main Parser… in Pharo4 we will remove the old Parser (subclass of Scanner ;-),
Other first plans (we need to start a real discussion after Pharo3 is released) for Pharo4 are in the in the Fosdem talk:
Slides: http://www.slideshare.net/MarcusDenker/2013-fosdempharo4 Video: https://www.youtube.com/watch?v=mUV9E03u52g
I think even this change should wait for Pharo4… but of course it can be prepared and ready for inclusion. (we need to be a bit careful what to change now, the side-effects of changes are always amazing ;-)
Marcus