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Line 16... Line 16...
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  True, False
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  True, False
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except NameError:
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except NameError:
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  (True, False) = (1, 0)
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  (True, False) = (1, 0)
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 19 
 
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import sys
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import sys
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21 
 
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class RecursiveDescentParser:
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class RecursiveDescentParser:
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    def __init__(self):
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    def __init__(self):
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        self.__clear()
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        self.__clear()
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    def __clear(self):
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    def __clear(self):
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                print 'Bad Selection'
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                print 'Bad Selection'
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                print
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                print
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    def __test_str(self):
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    def __test_str(self):
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        print 'Parsing: %s' % (self.procE() and 'Completed' or 'Failed', )
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        print 'Parsing: %s' % (self.procE() and 'Completed' or 'Failed', )
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        print
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    def procE(self):
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    def procE(self):
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        print 'procE(%s) ->' % (self.str[self.strpos:])
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        print 'procE(%s) ->' % (self.str[self.strpos:])
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62 
 
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        return self.procT() and self.procEprm()
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        return self.procT() and self.procEprm()
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- 
 
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    def procEprm(self):
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        # Check empty str
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        if self.strpos >= len(self.str):
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            return True
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        print 'procEprm(%s) ->' % (self.str[self.strpos:])
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        # Check +
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        if self.str[self.strpos] == '+':
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            self.strpos += 1
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            return self.procT() and self.procEprm()
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        # Check -
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        if self.str[self.strpos] == '-':
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            self.strpos += 1
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            return self.procT() and self.procEprm()
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        # We accept empty str, so take it
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        return True
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    def procT(self):
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    def procT(self):
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        print 'procT(%s) ->' % (self.str[self.strpos:])
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        print 'procT(%s) ->' % (self.str[self.strpos:])
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- 
 
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        if self.str[self.strpos] == '0':
 - 
 
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            self.strpos += 1
 - 
 
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            return True
 - 
 
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        return False
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        return self.procF() and self.procTprm()
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    def procEprm(self):
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    def procTprm(self):
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        # Check empty str
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        # Check empty str
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        if self.strpos >= len(self.str):
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        if self.strpos >= len(self.str):
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            return True
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            return True
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 94 
 
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        print 'procEprm(%s) ->' % (self.str[self.strpos:])
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        print 'procTprm(%s) ->' % (self.str[self.strpos:])
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 96 
 
- 
 
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        # Check *
80 
        if self.str[self.strpos] == '+' or self.str[self.strpos] == '-':
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        if self.str[self.strpos] == '*':
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            self.strpos += 1
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            return self.procF() and self.procTprm()
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        # we accept empty str, so take it
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        return True
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    def procF(self):
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        print 'procF(%s) ->' % (self.str[self.strpos:])
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        # Check x
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        if self.str[self.strpos] == 'x':
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            self.strpos += 1
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            return self.procV()
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- 
 
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        # Check (E)
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        if self.str[self.strpos] == '(':
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            self.strpos += 1
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            self.strpos += 1
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            if self.procE():
82 
            return self.procT() and self.procEprm()
 118 
                if self.str[self.strpos] == ')':
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                    return True
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            return False
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        # Must be a number
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        return self.procN()
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- 
 
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    def procN(self):
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        print 'procN(%s) ->' % (self.str[self.strpos:])
- 
 
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- 
 
 129 
        if self.str[self.strpos] in '0123456789':
- 
 
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            self.strpos += 1
- 
 
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            return True
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 132 
 
84 
        return False
 133 
        return False
85 
 
 134 
 
- 
 
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    def procV(self):
- 
 
 136 
        print 'procV(%s) ->' % (self.str[self.strpos:])
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- 
 
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        return self.procN()
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86 
if __name__ == '__main__':
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if __name__ == '__main__':
87 
    rdp = RecursiveDescentParser()
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    rdp = RecursiveDescentParser()
88 
    rdp.main_menu()
 142 
    rdp.main_menu()
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