compiler.py 文件源码

def parser(self):
        query_key = pp.Keyword("QUERY")
        query_value = pp.Suppress("|") + pp.SkipTo(pp.Suppress(";"), include=True)

        fields_key = pp.Keyword("FIELDS")
        field_name = common_parsers.column
        field_name_list = pp.Group(pp.delimitedList(field_name, delim=",")).setParseAction(lambda x: x.asList())

        fields_block = (pp.Suppress(fields_key) + field_name_list)

        connector_name = pp.Word(pp.alphas, pp.alphanums + "_$")
        using_block = pp.Suppress("USING") + connector_name

        then_key = pp.Suppress("THEN")
        manipulation_set = pp.Suppress("|") + pp.SkipTo(pp.Suppress(";"), include=True)
        then_block = then_key + manipulation_set

        as_key = pp.Suppress("AS")
        node_name = pp.Word(pp.alphas, pp.alphanums + "_$")
        as_block = as_key + node_name

        query_node_block = (pp.Suppress(query_key) + query_value + pp.Optional(fields_block, default=None) + using_block + pp.Optional(then_block, default=None) + as_block)
        query_node_block.setParseAction(lambda x: self._add_query_node(query_value=x[0],
                                                                       connector_name=x[2],
                                                                       node_name=x[4],
                                                                       fields=x[1],
                                                                       manipulation_set=x[3]))
        single_query_node = query_node_block + pp.Optional(pp.Suppress("---"))
        retrieve_block = pp.OneOrMore(single_query_node)
        return retrieve_block