准确无误买卖点指标出现“买”字改成选股公式

编写要求：

解答：

?网友求助：

公式源码如下：
ma3:ma(close,3),colorffffff,linethick1;
ma8:ma(close,8),color00ffff,linethick1;
ma49:ma(close,49),color00ff00,linethick2;
angel:ema(c,2),color000000;
devil:ema(slope(c,21)*20+c,42),pointdot,color000000;
buy:=cross(angel,devil);
sel:=cross(devil,angel);
stickline(cross(angel,devil) or cross (devil,angel),open,close,8,0),colorwhite;
drawtext(buy,low*0.98,'买'),colorf00ff0,linethick2;
drawtext(sel,high*1.02,'卖'),colorwhite,linethick2;