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1 #!/usr/bin/env python
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2
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3 """
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4 Extract Charactor from AST. Keywords,
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5 """
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6
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7 from pyrect.regexp.parser import Parser
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8 from pyrect.regexp.ast import ASTWalker
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9
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10 class CharCollector(ASTWalker):
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11 """ Extract with Visitor-Pattern.
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12 AST (ast), is represented by Node-Tree.
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13 >>> prs = Parser()
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14 >>> an = CharCollector()
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15 >>> an.analyze(prs.parse('.*(a|b)e'))
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16 ['a', 'b', (AnyChar:.), 'e']
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17 >>> an.analyze(prs.parse('\*+ \[\['))
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18 [' ', '*', '[']
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19 """
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20
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21 def __init__(self):
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22 self.chars = None
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23
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24 def analyze(self, ast=None):
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25 if ast:
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26 self.chars = list(set(ast.accept(self)))
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27 self.chars.sort()
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28 return self.chars
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29
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30 def visit(self, ast):
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31 """Following Classes contain no-Keywords.
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32 Union, Star
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33 """
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34 return [str(ast)]
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35
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36 def visit_AnyChar(self, anychar):
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37 return [anychar]
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38
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39 def visit_CharClass(self, cclass):
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40 chars = [chr(x) for x in cclass.get_chars()]
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41 return chars
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42
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43 def visit_Character(self, char):
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44 return [chr(char.char)]
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45
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46 def union(self, r1, r2):
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47 return r1 + r2
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48
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49 def concat(self, r1, r2):
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50 return r1 + r2
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51
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52 def test():
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53 import doctest
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54 doctest.testmod()
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55
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56 if __name__ == "__main__": test()
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