Python pyparsing 模块，CharsNotIn() 实例源码

def parse_format(format):
    definition = []

    # define pattern grammar
    variable_ptn = pp.QuotedString("{", endQuoteChar="}")("variable")
    escape_open_ptn = pp.Literal("{{")("escape_open")
    escape_close_ptn = pp.Literal("}}")("escape_close")
    escape_ptn = escape_open_ptn | escape_close_ptn
    literal_ptn = pp.CharsNotIn("{}")("literal")
    element_ptn = escape_ptn | variable_ptn | literal_ptn

    for toks, start, end in element_ptn.leaveWhitespace().scanString(format):
        try:
            definition.append({
                "literal": lambda: Literal(toks[0]),
                "variable": lambda: Variable.create(toks[0]),
                "escape_open": lambda: OpenBrace(),
                "escape_close": lambda: CloseBrace(),
            }[toks.items()[0][0]]())
        except KeyError:
            raise FormatStringError
    return definition

def __init__(self, rule):
        self.rule = rule
        self.opener = self.rule['opener']
        self.closer = self.rule['closer']
        self.columns = self.rule.get('columns', -1)

        nested = nestedExpr(opener=self.opener, closer=self.closer,
                            content=CharsNotIn(self.opener + self.closer))
        if self.columns < 0:
            self.nested = OneOrMore(nested)
        else:
            self.nested = nested * self.columns + Or([CharsNotIn('\n'), Empty()])