如何在tradingview pinescript中保持两个多头和空头相对头寸？

//@version=4
study("Dual Position Example", overlay=true)

// 定义变量
var float longPosition = na
var float shortPosition = na

// 计算多头和空头头寸
if condition_for_long_position
    longPosition := 1
    shortPosition := na
else if condition_for_short_position
    longPosition := na
    shortPosition := 1
else
    longPosition := na
    shortPosition := na

// 绘制多头和空头头寸
plotshape(longPosition, title="Long Position", location=location.belowbar, color=color.green, style=shape.labelup, text="Long")
plotshape(shortPosition, title="Short Position", location=location.abovebar, color=color.red, style=shape.labeldown, text="Short")