High Ema Low Ema Price Crossover for Amibroker (AFL)

_SECTION_BEGIN( "Price" );
SetChartOptions( 0, chartShowDates | chartShowArrows | chartLogarithmic | chartWrapTitle );
_N( Title = StrFormat( "{{NAME}} - " + SectorID( 1 ) + " - {{INTERVAL}} {{DATE}} Open %g, Hi %g, Lo %g, Close %g (%.1f%%) Vol " + WriteVal( V, 1.0 ) + " {{VALUES}}", O, H, L, C, SelectedValue( ROC( C, 1 ) ) ) );
Plot( C, "Close", colorRose, styleCandle | styleNoTitle | ParamStyle( "Style" ) | GetPriceStyle() );
_SECTION_END();

_SECTION_BEGIN("High Ema Low Ema Price Crossover");
x = EMA(Close,11);
y = EMA(High,11);
z = EMA(Low,11);
PH = Ref(High,-1); 
PL = Ref(Low,-1);	

Plot(EMA(Close,11),"",colorRed,styleLine);
Plot(EMA(Low,11),"",colorPaleGreen,styleLine);
Plot(EMA(High,11),"",colorDarkGreen,styleLine);

Buy= C>O AND C>Y AND C>ph;
Sell=C<Z;
Short= C<O AND C<Z AND C<PL;
Cover=C>Y; 

Buy=ExRem(Buy,Sell);
Short=ExRem(Short,Cover);
Sell=ExRem(Sell,Buy);
Cover=ExRem(Cover,Short);

PlotShapes(Buy* shapeUpArrow,colorBlue, 0,L, Offset=-45); 
PlotShapes(Short* shapeDownArrow,colorRed, 0,H, Offset=-45);

PlotShapes(Sell*shapeHollowDownArrow,colorPink,0,L,-45);
PlotShapes(Cover*shapeHollowUpArrow,colorSkyblue,0,H,-45);

/////////////////////////////////// Exploration ///////////////////////
Filter = Buy OR Sell;

/////////// General Columns ////////////////////////
AddTextColumn( FullName( ), "Name" ); 
AddColumn(C,"Close");
AddTextColumn( MarketID( 1 ), "Market name" ); 

//////////////// BUY/SELL SIGNALS ///////

AddColumn( IIf(Buy,1,IIf(Sell,-1,Null)) ,"Signal1",1.0,colorWhite,IIf(Buy,colorGreen,IIf(Sell,colorRed,colorWhite))); 


//////////////////////////////////// Exploration over ////////////////////////////