compiler.py 文件源码

def parser(self):
        join_type = (pp.Literal("LEFT") | pp.Literal("RIGHT") | pp.Literal("INNER") | pp.Literal("OUTER"))
        node_name = pp.Word(pp.alphas, pp.alphanums + "_$")

        col_name = pp.Word(pp.alphas, pp.alphanums + "_$")
        col_name_list = pp.Group(pp.delimitedList(col_name, delim=","))

        l_brac = pp.Suppress("[")
        r_brac = pp.Suppress("]")

        single_join = (join_type + pp.Suppress("(") + node_name + l_brac +
                       col_name_list + r_brac + pp.Suppress("==>") + node_name +
                       l_brac + col_name_list + r_brac + pp.Suppress(")"))

        single_join.addParseAction(lambda x: self._add_join(join_type=x[0],
                                                            child_node_name=x[1],
                                                            child_cols=x[2],
                                                            parent_node_name=x[3],
                                                            parent_cols=x[4]))
        join_block = pp.OneOrMore(single_join)
        return join_block