Error on Use of Highest Function

Hello Forum,

I am trying to write some code to display the 4 hour candles on the 5 minute chart. I have written some code and I receive and error that ‘a positive integer field is expected with the HIGHEST’. As I am trying to capture the current 4 hour data I cycle through the last candles up to 48 candles (48 * 5 mins = 4 hours) and then begin the new candle. So I am using a variable in the highest function called ‘currentBar’ which I expect to be the counted bars since the start of the current 4 hour candle. Is this error telling me I cannot use a variable in this location and can only use a written integer?

Any help on correcting this error would be appreciated.

PS – For now ignore how wide I am drawing the actual candlestick bodies, I had not reached that part of the project and had borrowed the candle drawing code from another indicator.

// Indicator Parameters
Period  = 48
CandleStart = 030001
CandleStop = 030059

ONCE startIndex = 0
ONCE CandleOpen = Open
ONCE CandleClose = Close
ONCE CandleHigh = High
ONCE CandleLow = Low

IF CurrentTime > CandleStart AND CurrentTime < CandleStop AND BarIndex > Period THEN
startIndex = BarIndex
ENDIF

IF BarIndex - startIndex > Period THEN
startIndex = BarIndex
ENDIF

// Current Bar Position
IF startIndex > 0 THEN
currentBar =  abs(BarIndex - startIndex)
ELSE
currentBar = abs(BarIndex)
ENDIF

// Calculate 4 Hr Open
IF startIndex > 0 THEN
CandleOpen = Open[currentBar]
ENDIF

// Calculate 4 Hr Close
IF startIndex > 0 THEN
CandleClose = Close[currentBar]
ENDIF

// Calculate 4 Hr High
IF startIndex > 0 THEN
CandleHigh = highest[currentBar]
ENDIF

// Calculate 4 Hr Low
IF startIndex > 0 THEN
CandleLow = lowest[currentBar]
ENDIF

// Draw Candle

//candlestick color
if CandleOpen>CandleClose then
direction = -1
else
direction = 1
endif

if direction = 1 then
// Candlestick body
DRAWRECTANGLE(barindex-5,CandleOpen,barindex,CandleClose) COLOURED(10,255,10)
// Candlestick high and low
DRAWRECTANGLE(barindex-3,CandleClose,barindex-2,CandleHigh) COLOURED(10,255,10)
DRAWRECTANGLE(barindex-3,CandleOpen,barindex-2,CandleLow) COLOURED(10,255,10)
endif
 
//bearish candle
if direction = -1 then
// Candlestick body
DRAWRECTANGLE(barindex-5,CandleClose,barindex,CandleOpen) COLOURED(255,10,10)
// Candlestick high and low
DRAWRECTANGLE(barindex-3,CandleOpen,barindex-2,CandleHigh) COLOURED(255,10,10)
DRAWRECTANGLE(barindex-3,CandleClose,barindex-2,CandleLow) COLOURED(255,10,10)
endif
return CandleOpen as "CandleOpen", CandleClose as "CandleClose", CandleHigh as "CandleHigh", CandleLow as "CandleLow"