Parabolic SAR in EasyLanguage — TradeStation & MultiCharts

EasyLanguage ships Wilder’s Parabolic SAR, which is welcome given how fiddly the recursive flip logic is to reproduce (see the explainer). Here’s the study and a stop-and-reverse strategy.

What you’ll need

• TradeStation or MultiCharts
• The EasyLanguage / PowerLanguage Editor, new Indicator

The source

TradeStation exposes the Parabolic SAR via the Parabolic reserved function, which fills variables by reference:

{ AlgoGen Parabolic SAR — TradeStation / MultiCharts }
inputs:
    AfStep( 0.02 ),
    AfMax( 0.20 );

variables:
    oParClose( 0 ),   { SAR value }
    oParOpen( 0 ),
    oPosition( 0 ),   { +1 long side, -1 short side }
    oTransition( 0 );

Value1 = Parabolic( AfStep, AfStep, AfMax, oParClose, oParOpen, oPosition, oTransition );

Plot1( oParClose, "SAR" );

Parabolic returns the SAR level in oParClose and the current side in oPosition — plot the SAR as dots (set the plot style to point/circles) to get the trailing dots from the output chart. (Simpler builds also expose a ParabolicSAR function returning just the value.)

A stop-and-reverse strategy

{ AlgoGen SAR System — Strategy }
inputs: AfStep( 0.02 ), AfMax( 0.20 );
variables: SARval( 0 );

SARval = ParabolicSAR( AfStep, AfMax );

if SARval < Close and SARval[1] >= Close[1] then
    Buy next bar at market
else if SARval > Close and SARval[1] <= Close[1] then
    SellShort next bar at market;

This reverses each time the SAR crosses price — the always-in behavior Wilder intended. Run the Strategy Performance Report, and consider adding an ADX filter to sit out the chop.

Gotchas

• Reference outputs. The full Parabolic function returns several values by reference (SAR, position, transition); assign the function’s return to a dummy (Value1) and read the ones you need.
• Plot as dots. Set the plot type to points so it reads as the classic SAR, not a continuous line.
• Always in the market. The pure system is never flat — filter it if your market ranges a lot.
• As a trailing stop only. If you enter on another signal, use the SAR purely to trail the exit: while long, Sell next bar at market when Close < SARval. This sidesteps the two-sided whipsaw of trading every flip.
• SetStopLoss / attach it. You can also feed the SAR level into a stop order so the platform manages the ratcheting exit for you, rather than checking it bar by bar.

Same indicator elsewhere: Python, MQL5, Pine Script, NinjaScript. Then backtest it in AlgoGen.

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This post is educational, not financial advice. Indicators describe the past; they don’t predict the future. Backtest anything before you risk real money on it.