‘

‘  two function are needed, left as an exercise  ;--- )

‘

‘     computeProfit – used to determine the profit upon exit of trade

‘                               based on the number of position taken.

‘       using

‘                exitprice, entries, entry count

‘

‘     computeGain – used to compute the open trade gain based on how many entries

‘                               have been taken

‘       using

‘                 todays close, entries, entry count
'
' note: By computing the gain the plot will reflect present value during open trades.
'           Also computeGain and computeProfit will need to assume some dollar value to invest.
'           The simple approach is just assume a fixed amount regardless of the ongoing performance
'           For example total of $10,000 for each symbol, entries ($1,000, $2,000, $3,000, $4,000)

static tradeOpen as boolean
static profit as single
static entries(5) as single ' using entrties 1 - 4
static tradeDays as integer

dim exitPrice as single
dim gain as single

if isfirstbar
   tradeOpen = false
   profit = 0
   entries(1) = 0
   entries(2) = 0
   entries(3) = 0
   entries(4) = 0
   nextPosition = 1
   tradeDays = 0
end if

if intrade = False then
   if entryCondition = true then

        entries(nextPosition) = price.close
        nextPosition += 1
   end if
else
   tradeDays += 1
   if tradeDays = 7 then
         '
         ' exit trade
         '
         exitPrice = price.close
         tradeDays = 0
         profit += computeProfiit(exitPrice,entries,nextPosition)

         nextPosiition = 1
   else
        '
        ' in trade, 
        '       check for adding to position

        ‘
        if nextPosition < 5 and price.close < entries(nextPosition -1) then

             ‘

             ‘   It is not realistic to buy as close but for now do it

             ‘

             entries(nextPosition) = price.close

             nextposition += 1

        end if
        '      
        '       compute position gain

        ‘

       gain = computeGain(price.close,entries,nextPosition – 1)
end if

plot = profit + gain

On sleeping on it I have a couple additional comments:

1. If used as a watchlist column '# Cumulative needs to be added since the indicator is plotting a result rerived from a static variable

2. Functions computeProfit and computeGain are really the same function, unless slippage and commission are included in the profit calculation

3. Setting gain to 0 at the top of the code might be prudent.

4. The entry condition is not provided. It could be a rule condition or whatever.

5. The code is untested and uncompiled but the concept works for calculating the equity curve per symbol for a strategy.

6. This is a simple money managment approach, unlimited funds and fixed trade size,  Starting with a profit based on initial equity of $10,000 and using the profit value as a parameter to calculateProfit and calculateGain would permit compounding and drawdown. 

If compounding is permitted, adding logic to limit the maximum trade size would avoid unrealistic returns based on unfillable trade sizes. 

Drawdown  would permit going bust during the test and not show when and if the stategy is viable under some market conditions.

7. Depending on the complexity of the chart, for large watchlist you might need to get a cup of coffee, or two, while it chugs along.

8. Making the number of entries into the position, currently 4, a userinput and adjusting the code would reveal if averaging down is a viable approach. As in 
a. 1 entry at 100% 
b. 2 entries at 33 and 67%
c. 3 enties at 17%, 33%, 50%
d. 4  entries at 10%, 20%, 30%, 40%
Adding entryCount as a parameter to calculateProfit and calulaterGain one could ignore the entry attempt when appropriate. My guess is that it typically doesn't pay to average down.

9. Making the timed exit, currenty 7 days, a user input would be another interesting dimention to study.

10. Enhancing the exit to include trailing stop based in the initial entry and profit target would be additional enhancements worth considering.