An n bar Reversal Indicator for Amibroker (AFL)

//An n Bar Reversal Program
//The theory says that this indicator gives reliable signals of strong trends.
//Its disadvantage is that the signal can be a little late, but is offset by its reliability.
// An uptrend is assumed to be in place if todays high is higher than those
// of the previous n days,and a downtrend is in place when todays low is lower

//than those of the previous n days. Otherwise the existing trend persists.
//n is commonly set at 3 but can be any value.
//The implementation here simply shows arrows at trend reversals.

n= Param("No. of Bars",3,2,8,1);
TrendUp = H > Ref(HHV(H,n),-1);
TrendDn = L < Ref(LLV(L,n),-1);
TrendUp = ExRem(TrendUp,TrendDn);
TrendDn = ExRem(TrendDn,TrendUp);
PlotShapes(TrendUp*shapeUpArrow,colorGreen);
PlotShapes(TrendDn*shapeDownArrow,colorRed);