问风险管理:如果已经很久，就不要下新订单。

EN

//@version=4
study("My Script", overlay=true)

var isLong = false
var isShort = false

rsi = rsi(close, 14)
moving_avg = ema(close, 9)

buySignal = not isLong and (rsi<50) and (close>moving_avg)    // Buy only if we are not already long
sellSignal = not isShort and (rsi>50) and (close<moving_avg)  // Sell only if we are not already short

if buySignal
    isLong := true
    isShort := false

if sellSignal
    isLong := false
    isShort := true

plotshape(series=buySignal, title="BUY", text="BUY", style=shape.triangleup, location=location.belowbar, color=color.green, size=size.small)
plotshape(series=sellSignal, title="SELL", text="SELL", style=shape.triangledown, location=location.abovebar, color=color.red, size=size.small)