在Macro中的%Do %While() 循环为何有问题呢？
提示错误为：
ERROR: A character operand was found in the %EVAL function or %IF condition where a numeric
       operand is required. The condition was: &d<=1
ERROR: The condition in the %DO %WHILE loop, , yielded an invalid or missing value, .  The
       macro will stop executing.
ERROR: The macro ERR will stop executing.



我尝试将%While改为 %do %while(%nrstr(&d) <=1); 则条件就不起作用了，会一直执行下去。

哪位仁兄能指点一下呀？