Fibonacci Retracement in EasyLanguage — TradeStation & MultiCharts

EasyLanguage doesn’t have a scripted “fib tool,” but computing the levels from a rule-based swing and plotting them as horizontal lines is straightforward — and more testable than eyeballing. See the explainer for the concept.

What you’ll need

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

The source

{ AlgoGen Fibonacci Retracement — TradeStation / MultiCharts }
inputs:
    Lookback( 90 );

variables:
    SwingHigh( 0 ), SwingLow( 0 ), Diff( 0 );

SwingHigh = Highest( High, Lookback );
SwingLow  = Lowest( Low, Lookback );
Diff = SwingHigh - SwingLow;

{ Each plotted line is a retracement level measured up from the low }
Plot1( SwingLow + 0.000 * Diff, "0%" );
Plot2( SwingLow + 0.236 * Diff, "23.6%" );
Plot3( SwingLow + 0.382 * Diff, "38.2%" );
Plot4( SwingLow + 0.500 * Diff, "50%" );
Plot5( SwingLow + 0.618 * Diff, "61.8%" );
Plot6( SwingLow + 0.786 * Diff, "78.6%" );
Plot7( SwingLow + 1.000 * Diff, "100%" );

Highest/Lowest pick the swing by rule, and each plot is SwingLow + ratio × Diff — the same arithmetic as everywhere else, rendered as horizontal lines that step as the swing updates, matching the output chart.

Testing whether a level holds

variables: GoldenLow( 0 ), GoldenHigh( 0 );
GoldenLow  = SwingLow + 0.382 * Diff;
GoldenHigh = SwingLow + 0.618 * Diff;

if Close >= GoldenLow and Close <= GoldenHigh then
    Alert( "Price in the Fibonacci golden zone" );

Adding extension targets

Beyond the retracement, Fibonacci extensions project targets past the 100% level — handy for exits. Add them with the same arithmetic:

Plot8( SwingLow + 1.272 * Diff, "127.2%" );
Plot9( SwingLow + 1.618 * Diff, "161.8%" );

161.8% is the golden ratio projected beyond the swing — a common profit target once a retracement holds and the trend resumes.

Gotchas

• The swing is a rule here. Using Highest/Lowest over a lookback keeps it objective; that’s what makes it backtestable rather than hindsight-fit.
• Lines will “walk.” Because the swing updates each bar, the plotted levels shift when a new high or low forms — expected behavior for an auto-fib, but different from a hand-drawn, fixed fib.
• 50% isn’t Fibonacci — it’s included by convention (Dow Theory).

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.