/*********************************************************
Alexis C. Montenegro © June 2006                          
Use and/or modify this code freely. If you redistribute it
please include this and/or any other comment block and a  
description of any changes made.                          
**********************************************************/

// NOTE:                                                                          
// This efs requires amFunctions.efsLib in the FunctionLibrary folder.            
// If you do not have this file you can download it at the link below.            
// http://share.esignal.com/groupcontents.jsp?folder=Formulas-Libraries&groupid=10

var fpArray = new Array();

function preMain(){
    setPriceStudy(false);
    setStudyTitle("Linear Regression Slope");
    setCursorLabelName("LRS");
    setDefaultBarFgColor(Color.blue);
    setDefaultBarThickness(1);
    var x=0;
    fpArray[x] = new FunctionParameter("Length", FunctionParameter.NUMBER);
	with(fpArray[x++]){
        setLowerLimit(1);		
        setDefault(10);
    }
	fpArray[x] = new FunctionParameter("Source", FunctionParameter.STRING);
	with(fpArray[x++]){
        addOption("open"); 
        addOption("high");
        addOption("low");
        addOption("close");
        addOption("hl2");
        addOption("hlc3");
        addOption("ohlc4"); 
        setDefault("close"); 
    }
    fpArray[x] = new FunctionParameter("Symbol", FunctionParameter.STRING);
    with(fpArray[x++]){
        setDefault();
	}
	fpArray[x] = new FunctionParameter("Interval", FunctionParameter.STRING);
	with(fpArray[x++]){
        setDefault();
    }
    fpArray[x] = new FunctionParameter("Params", FunctionParameter.BOOLEAN);
	with(fpArray[x++]){
        setName("Show Parameters");
        setDefault(false);
    }
}

var amLib = addLibrary("amFunctions.efsLib");
var bInit = false;
var xLRS  = null;

function main(Length,Source,Symbol,Interval,Params){
    if(bInit==false){
        with( amLib ){
            if(Symbol == null) Symbol = getSymbol();
            if(Interval == null) Interval = getInterval();
            var vSymbol = Symbol+","+Interval;
            xLRS = getSeries(amLinRegSlope(Length,eval(Source)(sym(vSymbol))));
            addBand(0,PS_SOLID,1,Color.black,"0");
            setShowTitleParameters(eval(Params));
            bInit=true;
        }
    }
    return xLRS;
}