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#
# Licensed to the Apache Software Foundation (ASF) under one
# or more contributor license agreements. See the NOTICE file
# distributed with this work for additional information
# regarding copyright ownership. The ASF licenses this file
# to you under the Apache License, Version 2.0 (the
# "License"); you may not use this file except in compliance
# with the License. You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing,
# software distributed under the License is distributed on an
# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
# KIND, either express or implied. See the License for the
# specific language governing permissions and limitations
# under the License.
#
class ParseError(Exception):
def __init__(self, token, *expected):
line, ln, col = token.line_info()
exp = ", ".join(map(str, expected))
if len(expected) > 1:
exp = "(%s)" % exp
if expected:
msg = "expecting %s, got %s line:%s,%s:%s" % (exp, token, ln, col, line)
else:
msg = "unexpected token %s line:%s,%s:%s" % (token, ln, col, line)
Exception.__init__(self, msg)
self.token = token
self.expected = expected
class Parser:
def __init__(self, tokens):
self.tokens = tokens
self.idx = 0
def next(self):
return self.tokens[self.idx]
def matches(self, *types):
return self.next().type in types
def eat(self, *types):
if types and not self.matches(*types):
raise ParseError(self.next(), *types)
else:
t = self.next()
self.idx += 1
return t
def eat_until(self, *types):
result = []
while not self.matches(*types):
result.append(self.eat())
return result
def remove(self, start, end):
start_idx = self.tokens.index(start)
end_idx = self.tokens.index(end) + 1
del self.tokens[start_idx:end_idx]
self.idx -= end_idx - start_idx
def reset(self):
self.idx = 0
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