Introduction to the library() Function

The library() function in Pine Script is a declaration statement that identifies a script as a library. Libraries in Pine Script are used to create modular, reusable code that can be imported and used in other scripts. This functionality is crucial for developers who want to build a collection of commonly used functions and access them across multiple scripts.

Syntax of the library() Function

The general syntax of the library() function is as follows:

library(title, overlay) → void

Arguments

1. title (const string): This argument represents the title of the library and serves as its unique identifier. The title must adhere to specific rules:
   • It cannot contain spaces or special characters.
   • It cannot begin with a digit.
   • The title is used as the publication’s default title and to uniquely identify the library in the import statement when another script uses it.
   • It also serves as the script’s name on the chart.
2. overlay (const bool): This boolean argument determines how the library is displayed.
   • If set to true, the library will be added over the chart.
   • If false (which is the default value), it will be added in a separate pane.

Example

Consider an example where we create a simple math library to calculate the hyperbolic sine function:

//@version=5
// @description Math library
library("num_methods", overlay = true)

// Calculate "sinh()" from the float parameter `x`
export sinh(float x) =>
    (math.exp(x) - math.exp(-x)) / 2.0

plot(sinh(0))

In this example:

• The library is declared with the title num_methods and is set to overlay on the chart (overlay = true).
• We define a function sinh using the export keyword, making it available for use in other scripts that import this library.
• The sinh function calculates the hyperbolic sine of a given float parameter x.
• Finally, we use the plot function to display the value of sinh(0) on the chart.

Key Features and Takeaways

• Function Usability: The library() function is essential for creating modular, reusable code in Pine Script, improving code organization and efficiency.
• Syntax and Application: Its syntax is straightforward, with the title and overlay arguments, making it easy to declare and use.
• Overlay Option: The overlay argument provides flexibility in how the library’s output is displayed on the chart, catering to different visualization needs.

By understanding and utilizing the library() function, Pine Script users can significantly enhance their scripting capabilities, leading to more organized, efficient, and reusable code in their trading analysis.