imcfilter.py 文件源码

def parse_filter_str(self, filter_str):
        """
        method to parse filter string
        """

        prop = pp.WordStart(pp.alphas) + pp.Word(pp.alphanums +
                                                 "_").setResultsName("prop")
        value = (pp.QuotedString("'") | pp.QuotedString('"') | pp.Word(
            pp.printables, excludeChars=",")).setResultsName("value")
        types_ = pp.oneOf("re eq ne gt ge lt le").setResultsName("types")
        flags = pp.oneOf("C I").setResultsName("flags")
        comma = pp.Literal(',')
        quote = (pp.Literal("'") | pp.Literal('"')).setResultsName("quote")

        type_exp = pp.Group(pp.Literal("type") + pp.Literal(
            "=") + quote + types_ + quote).setResultsName("type_exp")
        flag_exp = pp.Group(pp.Literal("flag") + pp.Literal(
            "=") + quote + flags + quote).setResultsName("flag_exp")

        semi_expression = pp.Forward()
        semi_expression << pp.Group(pp.Literal("(") +
                                    prop + comma + value +
                                    pp.Optional(comma + type_exp) +
                                    pp.Optional(comma + flag_exp) +
                                    pp.Literal(")")
                                    ).setParseAction(
            self.parse_filter_obj).setResultsName("semi_expression")

        expr = pp.Forward()
        expr << pp.operatorPrecedence(semi_expression, [
            ("not", 1, pp.opAssoc.RIGHT, self.not_operator),
            ("and", 2, pp.opAssoc.LEFT, self.and_operator),
            ("or", 2, pp.opAssoc.LEFT, self.or_operator)
        ])

        result = expr.parseString(filter_str)
        return result