ATR Trailing Stop (Pine Script Port)
ATR Trailing Stop (Pine Script port)
A worked example of converting a TradingView Pine Script indicator to MQL5, kept in parity with a Python reference implementation.
Rules (same in all three versions):
– nLoss = ATR multiplier x SMA of true range over InpATRLength bars
– The stop ratchets up under price while price stays above it, and down over price while price stays below it
– The stop flips to the other side, and an arrow is drawn, when price closes through it
Pine to MQL5/Python translation notes (the actual porting work):
– ta.tr(true): the first bar has no previous close, so true range there is just high minus low
– ta.sma(x, n): stays na until n bars exist (first valid value at bar n-1)
– nz(stop[1], src): the previous stop, or the current price while the previous stop is still na
– var float stop = na: state carried from bar to bar, translated to a persistent buffer in MQL5 and a running array in Python
– ta.crossover / ta.crossunder: strictly false while either side is na, which matters for the first valid bar
Repository (Pine source, Python port with a literal bar-by-bar reference implementation for cross-checking, and a parity test comparing both to the MQL5 output): github.com/RAo797bit/pine-python-mql5-conversion
Compiles clean in MetaEditor with 0 errors, 0 warnings 
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