User-defined functions in Pine Script™ are custom functions written by the programmer, differing from the built-in functions provided within the language. These functions are essential for executing repetitive calculations or for performing unique operations that are not covered by Pine Script’s built-in functionalities.
Key Characteristics of User-Defined Functions
- Non-Embedded Nature: All user-defined functions in Pine Script are defined in the script’s global scope, meaning they cannot be embedded within other functions.
- Recursion Limitation: User-defined functions do not support recursion. A function cannot call itself from within its code in Pine Script.
- Dynamic Return Types: The return type of a function in Pine Script is automatically determined and varies depending on the argument types used in each function call.
- Return Value Determination: The value returned by a function is always the last value computed in the function’s body.
- Independent Function Call Histories: Each instance where a function is called in a script maintains its independent history, ensuring isolated calculations and results for each call.
Writing User-Defined Functions
User-defined functions in Pine Script can be written in two primary ways:
- Single-Line Functions: Suitable for simple calculations or operations, these functions are concise and written in a single line.
- Multi-Line Functions: For more complex operations, functions can span multiple lines, allowing for detailed and intricate calculations.
Placement of Functions
- Within a Single Script: If a function is specific to a particular script, it can be included directly within that script. It’s important to follow style guidelines for the placement of functions within the script for better readability and structure.
- Pine Script Libraries: For functions that are reusable across different scripts, creating a Pine Script library is advisable. This approach promotes reusability and avoids duplication of code. Library functions have specific requirements as outlined in the Pine Script library documentation.
Conclusion and Key Takeaways
- User-defined functions extend the capabilities of Pine Script.
- They must be defined in the global scope and cannot be recursive.
- The return type is dynamically determined by the argument types used.
- Functions maintain independent histories for each call, ensuring isolated and accurate calculations.
Next, we will delve into practical examples of writing and using user-defined functions in Pine Script, highlighting the process with distinct variable names for a clearer understanding. Stay tuned for more insights into harnessing the power of custom functions in your Pine Script programming.