tvl-depot/users/wpcarro/scratch/facebook/parsing/parser.py
Vincent Ambo 019f8fd211 subtree(users/wpcarro): docking briefcase at '24f5a642'
git-subtree-dir: users/wpcarro
git-subtree-mainline: 464bbcb15c
git-subtree-split: 24f5a642af
Change-Id: I6105b3762b79126b3488359c95978cadb3efa789
2021-12-14 02:15:47 +03:00

28 lines
706 B
Python

class Parser(object):
def __init__(self, tokens):
self.tokens = tokens
self.i = 0
def prev(self):
return self.tokens[self.i - 1]
def curr(self):
return self.tokens[self.i]
def consume(self):
if not self.exhausted():
self.i += 1
return self.prev()
def match(self, xs):
if not self.exhausted() and self.curr() in xs:
self.consume()
return True
return False
def expect(self, xs):
if not self.match(xs):
raise Exception("Expected token \"{}\" but received \"{}\"".format(xs, self.curr()))
def exhausted(self):
return self.i >= len(self.tokens)