manipulation_set.py 文件源码

def parser(cls):
        lpar = pp.Suppress("(")
        rpar = pp.Suppress(")")
        mutate = pp.Suppress('mutate')
        col_name = pp.Word(pp.alphas, pp.alphanums + "_$")

        expr_evaluator = Evaluator(deferred_eval=True)
        col_expr = expr_evaluator.parser()

        mutation = col_name + pp.Suppress("=") + col_expr
        mutation.setParseAction(lambda x: {'col_name': x[0], 'col_expr': x[1]})
        mutations = pp.Group(pp.delimitedList(mutation))
        parser = mutate + lpar + mutations + rpar
        parser.setParseAction(lambda x: Mutate(mutations=x))
        return parser