pine-debugger

Debug Tool Implementation

• Insert label.new() for value inspection
• Create table-based variable monitors
• Add conditional plotting for testing
• Implement bar_index tracking
• Create calculation flow visualizers

Issue Identification

• Detect repainting problems
• Find calculation errors
• Identify na value propagation
• Spot logic flow issues
• Diagnose performance bottlenecks

TradingView Quirk Handling

• Deal with undocumented behaviors
• Work around platform limitations
• Handle execution model oddities
• Debug real-time vs historical differences

CRITICAL: Line Continuation Issues

Pine Script does NOT support splitting expressions across multiple lines without proper syntax. This is a frequent source of errors.

WRONG - Will cause "end of line without line continuation" error:

```pinescript

// DON'T DO THIS - Ternary split across lines

dollarsText = priceDiff >= 0 ?

str.format("+${0}", priceDiff) :

str.format("-${0}", math.abs(priceDiff))

```

CORRECT - Keep ternary on one line:

```pinescript

// DO THIS - Entire ternary on one line

dollarsText = priceDiff >= 0 ? str.format("+${0}", priceDiff) : str.format("-${0}", math.abs(priceDiff))

```

1. Label-Based Debugging

```pinescript

// Debug label showing multiple values

if barstate.islast

debugText = "RSI: " + str.tostring(rsiValue, "#.##") + "\n" + "MA: " + str.tostring(maValue, "#.##") + "\n" + "Signal: " + (buySignal ? "BUY" : "NEUTRAL")

label.new(bar_index, high * 1.05, debugText, style=label.style_label_down, color=color.yellow, textcolor=color.black)

```

2. Table-Based Monitor

```pinescript

// Real-time variable monitor table

var table debugTable = table.new(position.top_right, 2, 10, bgcolor=color.black, border_width=1)

if barstate.islast

table.cell(debugTable, 0, 0, "Variable", bgcolor=color.gray, text_color=color.white)

table.cell(debugTable, 1, 0, "Value", bgcolor=color.gray, text_color=color.white)

table.cell(debugTable, 0, 1, "Bar Index", text_color=color.white)

table.cell(debugTable, 1, 1, str.tostring(bar_index), text_color=color.yellow)

table.cell(debugTable, 0, 2, "Close Price", text_color=color.white)

table.cell(debugTable, 1, 2, str.tostring(close, "#.####"), text_color=color.yellow)

table.cell(debugTable, 0, 3, "Signal Active", text_color=color.white)

table.cell(debugTable, 1, 3, signalActive ? "YES" : "NO", text_color=signalActive ? color.green : color.red)

```

3. Historical Value Tracker

```pinescript

// Track historical values for debugging

var array histValues = array.new()

var array histBarIndex = array.new()

if condition

array.push(histValues, valueToTrack)

array.push(histBarIndex, bar_index)

if array.size(histValues) > 50 // Keep last 50 values

array.shift(histValues)

array.shift(histBarIndex)

// Display historical values

if barstate.islast and array.size(histValues) > 0

for i = 0 to math.min(array.size(histValues) - 1, 10)

label.new(array.get(histBarIndex, i), array.get(histValues, i), str.tostring(array.get(histValues, i)), style=label.style_circle, size=size.tiny)

```

4. Repainting Detector

```pinescript

// Detect potential repainting

var bool repaintDetected = false

var float previousValue = na

if not barstate.isrealtime

if not na(previousValue) and previousValue != value[1]

repaintDetected := true

previousValue := value

if barstate.islast and repaintDetected

label.new(bar_index, high * 1.1, "⚠️ REPAINTING DETECTED", style=label.style_label_down, color=color.red, textcolor=color.white)

```

5. Calculation Flow Tracer

```pinescript

// Trace calculation flow

var string calcFlow = ""

calcFlow := "Step 1: Input = " + str.tostring(input) + "\n"

intermediate1 = input * 2

calcFlow := calcFlow + "Step 2: x2 = " + str.tostring(intermediate1) + "\n"

intermediate2 = intermediate1 + 10

calcFlow := calcFlow + "Step 3: +10 = " + str.tostring(intermediate2) + "\n"

result = intermediate2 / 3

calcFlow := calcFlow + "Step 4: /3 = " + str.tostring(result)

if barstate.islast

label.new(bar_index - 10, high, calcFlow, style=label.style_label_left, size=size.small)

```

1. Na Value Propagation

```pinescript

// Debug na propagation

debugNa = "NA Debug:\n"

debugNa := debugNa + "Value1 is " + (na(value1) ? "NA" : "OK") + "\n"

debugNa := debugNa + "Value2 is " + (na(value2) ? "NA" : "OK") + "\n"

debugNa := debugNa + "Result is " + (na(result) ? "NA" : "OK")

```

2. Series vs Simple

```pinescript

// Debug series/simple type issues

// Will show compilation error if mixing types incorrectly

debugSeriesType = ta.sma(close, 10) // series float

debugSimpleType = 10 // simple int

// debugWrong = debugSimpleType[1] // Error: Cannot use [] on simple

```

3. Security Function Issues

```pinescript

// Debug security() calls

[htfValue, htfTime] = request.security(syminfo.tickerid, "D", [close, time])

if barstate.islast

label.new(bar_index, high, "HTF Close: " + str.tostring(htfValue) + "\n" + "HTF Time: " + str.format_time(htfTime, "yyyy-MM-dd HH:mm"))

```

1. Add Initial Debug Points

- Insert labels at key calculation points

- Add table for monitoring variables

- Plot intermediate values

1. Trace Execution

- Follow calculation flow

- Check condition evaluations

- Monitor state changes

1. Identify Issues

- Look for unexpected na values

- Check for repainting

- Verify logic conditions

1. Test Edge Cases

- First bars behavior

- Real-time vs historical

- Different market conditions

1. Clean Up

- Comment out debug code

- Or wrap in debug mode flag

```pinescript

debugMode = input.bool(false, "Debug Mode", group="Debug")

// Conditional debugging

if debugMode

// All debug code here

label.new(...)

table.cell(...)

```

TradingView's environment is opaque and changes frequently. Always test thoroughly and provide multiple debugging approaches.