Writing AFL code requires adhering to specific syntax rules. Missing punctuation or incorrect case-sensitivity can break your script.
However, it requires understanding of vectorized operations and static variables for advanced logic. Well-written AFL code is even on large historical datasets.
In the world of retail algorithmic trading, few platforms offer the perfect blend of power, speed, and customization like . For over two decades, professional traders and hobbyists alike have relied on AmiBroker for backtesting, scanning, and real-time trading. The secret sauce behind this dominance is AFL (AmiBroker Formula Language) .
AmiBroker stores price data in predefined arrays. The most common native arrays are: O or Open (Opening price) H or High (Highest price) L or Low (Lowest price) C or Close (Closing price) V or Volume (Volume traded) OI or OpenInt (Open Interest) Variables and Assignment amibroker afl code
You can override AmiBroker’s core logic using SetCustomBacktestProc .
// Variable assignment (case-sensitive) myVar = Close; // assign whole array myScalar = 1.5; // constant number myString = "Hello";
While AFL supports looping ( for , while ), it is rarely needed for standard indicators. Logic is typically handled via logical operators: Writing AFL code requires adhering to specific syntax rules
AvgVol = MA(V, 20); Spike = V > 2 * AvgVol; Plot(Spike, "Volume Spike", colorRed, styleHistogram);
// Relative Strength Index (RSI) RSI(14);
Building an indicator involves calculating mathematical arrays and plotting them visually on the screen. Let us build a dual Moving Average Crossover indicator with dynamic color bands. Well-written AFL code is even on large historical datasets
AFL serves as the engine for four primary functions within the AmiBroker platform : AFL Reference Manual - AmiBroker
// Screen for stocks making 52-week highs with high volume High52 = HHV( High, 252 ); VolumeFilter = MA( Volume, 20 ) > 100000; Filter = Close == High52 AND VolumeFilter; // Append data to the display spreadsheet AddColumn( Close, "Closing Price", 1.2 ); AddColumn( Volume, "Volume Today", 1.0 ); AddColumn( ROC( Close, 1 ), "Daily Change %", 1.2 ); Use code with caution. 6. Best Practices for Professional AFL Development
AmiBroker excels at historical simulation. To create a backtest, you must define specific reserved variables that the AmiBroker engine looks for: Buy , Sell , Short , and Cover . Here is a complete :
// Indicator calculation FastMA = MA(C, PeriodFast); SlowMA = MA(C, PeriodSlow);
AFL is a proprietary, C-like scripting language designed specifically for AmiBroker. It is highly optimized, allowing for extremely fast calculations, which is critical when analyzing high-frequency data or conducting complex optimizations across thousands of data points. Key Uses of AFL: