如何修复Pine Script v4指标无法过滤连续Buy/Sell信号的问题

问题根因 #

• 仓位状态未持久化存储
  你编写的Longposition = false、Shortposition = false没有使用var关键字声明，每根K线计算时都会被重置为初始值false，之前修改的仓位状态完全无法留存到下一根K线，过滤逻辑自然无法生效。
• 逻辑判断优先级错误
  Pine Script中and运算符优先级高于or，原代码的Long = Longposition==false and Buy or Buyconf实际等价于(Longposition==false and Buy) or Buyconf，只要Buyconf为真，不管Longposition是不是true都会触发Long信号，连续信号过滤规则完全没有生效，Sell信号存在同样的问题。
• 隐藏问题：使用未来数据
  你调用security函数时使用了barmerge.lookahead_on参数，会在当前K线引用还未走完的30分钟K线数据，回测结果会严重失真，实盘运行时信号会频繁漂移。

修正后代码 #

//@version = 4
study("openclosedelta", shorttitle="openclosedelta", overlay=true)

// 若确实需要前瞻模式可自行改回lookahead_on，注意信号漂移风险
closeconf = security(symbol=syminfo.tickerid, resolution="30", expression=close, lookahead=barmerge.lookahead_off)
openconf = security(symbol=syminfo.tickerid, resolution="30",expression=open, lookahead=barmerge.lookahead_off)

// var关键字声明的变量仅在脚本初始化时赋值一次，不会每根K线重置
var bool Longposition = false
var bool Shortposition = false


Buy =   open>close[1] and open[1]>close[2]
Buyconf = openconf>closeconf[1] and openconf[1]>closeconf[2]
    
Sell =  open<close[1] and open[1]<close[2]
Sellconf = openconf<closeconf[1] and openconf[1]<closeconf[2]


// 添加括号调整逻辑优先级，只有空仓时满足任意买入条件才触发信号
Long = Longposition==false and (Buy or Buyconf)
Short = Shortposition==false and (Sell or Sellconf)

if Long
    Longposition := true
    Shortposition := false
   
    
if Short
    Shortposition := true
    Longposition := false
    


plotshape(Long ,"AL", text="BUY", location=location.belowbar, style=shape.labelup, size=size.tiny, color=color.green, textcolor=color.white)
plotshape(Short ,"SAT", text="SELL", location=location.abovebar, style=shape.labeldown, size=size.tiny, color=color.red, textcolor=color.white)

内容的提问来源于stack exchange，提问作者Ovgu Sayan