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