def seek(self, index):
        
        if index <= self.p:
            self.p = index # just jump; don't update stream state (line, ...)
            return

        # seek forward, consume until p hits index
        while self.p < index:
            self.consume()
consume() ahead until p==index; can't just set p=index as we must
dataset/ETHPy150Open AppScale/appscale/AppServer/lib/antlr3/antlr3/streams.py/ANTLRStringStream.seek