2013 Apr: Low-Frequency Trading, by Ron McEwan

 
/*********************************
Provided By:  
eSignal (Copyright c eSignal), a division of Interactive Data 
Corporation. 2012. All rights reserved. This sample eSignal 
Formula Script (EFS) is for educational purposes only and may be 
modified and saved under a new file name.  eSignal is not responsible
for the functionality once modified.  eSignal reserves the right 
to modify and overwrite this EFS file with each new release.

Description:     
    Low-Frequency Trading, by Ron McEwan

Version:            1.00  02/08/2013

Formula Parameters:                         Default:
SMA Length                                  253
Long Position Color                         lime
Short Position Color                        red

Notes:
The related article is copyrighted material. If you are not a subscriber
of Stocks & Commodities, please visit www.traders.com.

**********************************/

var fpArray = new Array();

function preMain()
{       
    setStudyTitle("OneYear_CumAdvDecMA");    
    setIntervalsBackfill(true);
    
    setCursorLabelName("Cum AD Line",0);    
    setCursorLabelName("MA",1);
    
    setDefaultBarFgColor(Color.blue, 0); 
    setDefaultBarFgColor(Color.purple, 1); 
    
    var x = 0;
    
    fpArray[x] = new FunctionParameter("gLength", FunctionParameter.NUMBER);
    with(fpArray[x++])
    {
        setName("SMA Length");        
        setLowerLimit(1);
        setDefault(253); 
    }     

    fpArray[x] = new FunctionParameter("gBuyColor", FunctionParameter.COLOR);
    with(fpArray[x++])
    {
        setName("Long Position Color");    
        setDefault(Color.lime);
    } 
    
    fpArray[x] = new FunctionParameter("gSellColor", FunctionParameter.COLOR);
    with(fpArray[x++])
    {
        setName("Short Position Color");    
        setDefault(Color.red);
    } 

}

var bInit = false;
var bVersion = null;

var xCumAd = null;
var xSMA = null;

function main(gLength,gBuyColor,gSellColor)
{
    if (bVersion == null) bVersion = verify();
    if (bVersion == false) return; 
  
    if (!bInit)
    {        
        xCumAd=efsInternal("getCumAd");
        xSMA = sma(gLength,xCumAd);
    }  

    var nCumAd = xCumAd.getValue(0);
    var nSMA = xSMA.getValue(0);

    if (nCumAd == null || nSMA == null) return;
    
    
    if (getCurrentBarIndex() != 0) 
    {       
            var bLStrategy = Strategy.isLong();            
            
            if (!bLStrategy)
            {
                if (nCumAd>nSMA)
                {
                   Strategy.doLong("Enter Long", Strategy.CLOSE, Strategy.THISBAR);                                                    
                   drawShapeRelative(0, BottomRow3,Shape.DIAMOND,null, gBuyColor, Shape.PRESET);
                }           
            }            
            else
            {
                if (nCumAd<nSMA)
                {
                    Strategy.doSell("Close Long", Strategy.CLOSE, Strategy.THISBAR);                      
                    drawShapeRelative(0, TopRow3,Shape.DIAMOND,null, gSellColor, Shape.PRESET);
                }        
            }     
    }
    
    return new Array(nCumAd,nSMA);        
}

var bCumAd = false;

var xAdv = null;
var xDecl = null;

var cumAd = 0;

function getCumAd()
{
    if (getBarState() == BARSTATE_ALLBARS)
    {
        bCumAd = false;
    }

     if(!bCumAd)
    {
        xAdv = close(sym("$ADV,D"));
        xDecl = close(sym("$DECL,D"));    
        cumAd = 0;
        
        bCumAd = true;
    }

    var nAdv = xAdv.getValue(0);
    var nDecl = xDecl.getValue(0);

    if (nAdv == null || nDecl == null || (nAdv+nDecl)==0) return;
    
    var pctChg = (nAdv-nDecl)/(nAdv+nDecl)*1000;
    
    var ret = ref(-1);
    
    cumAd = ret + pctChg; 
    
    return cumAd;
}

function verify() {
    var b = false;
    if (getBuildNumber() < 779) {
        drawTextAbsolute(5, 35, "This study requires version 8.0 or later.", 
            Color.white, Color.blue, Text.RELATIVETOBOTTOM|Text.RELATIVETOLEFT|Text.BOLD|Text.LEFT,
            null, 13, "error");
        drawTextAbsolute(5, 20, "Click HERE to upgrade.@URL=http://www.esignal.com/download/default.asp", 
            Color.white, Color.blue, Text.RELATIVETOBOTTOM|Text.RELATIVETOLEFT|Text.BOLD|Text.LEFT,
            null, 13, "upgrade");
        return b;
    } else {
        b = true;
    }
    return b;
}