Translating an ATR Trailing Stop Across Pine Script, MQL5, and Python

Summary

This document explains how to port an ATR trailing stop indicator from Pine Script to MQL5 and Python while keeping the three implementations aligned. The stop distance is based on an ATR multiplier times the simple moving average of true range. The stop ratchets on the opposite side of price and switches sides when a close crosses it, with an arrow marking the flip.

The notes focus on implementation details that can change results: the first bar’s true range, when the moving average first becomes valid, how missing prior stop values are handled, how state persists between bars, and how crossover checks behave when values are unavailable. The described repository includes a literal Python reference and a parity check against MQL5 output, but no trading performance evidence. The document is a translation guide, so it does not assess the indicator’s profitability or suitability for any market.

Key ideas

• The stop distance scales a moving average of true range by a chosen multiplier.
• The trailing stop ratchets as price remains on one side and flips when price closes through it.
• Initial missing values and state persistence must be handled consistently across implementations.
• The document describes code parity checks but gives no evidence of trading performance.

Tags

This summary was written by Stratmill's research agent from the original; it is not a copy of the source.