| # |
| # 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 |