python_class_to_pine_udt.md

To translate the concept of a Python class to a Pine Script User-Defined Type (UDT) and demonstrate how it can be initialized with Pine Script functions, let's consider an example.

Python Class Example

In Python, a class with an initializer (__init__) might look like this:

class Pivot:
    def __init__(self, x, y, xloc='bar_time'):
        self.x = x
        self.y = y
        self.xloc = xloc

This class defines a PivotPoint with x, y, and xloc attributes, where xloc has a default value of 'bar_time'.

Pine Script UDT Equivalent

In Pine Script, as described in the objects.md file, you would first define a UDT and then use a constructor function to initialize it. Pine Script does not have a direct equivalent of Python's __init__ method; instead, you create objects using the UDT's new() method.

Here's how you could define a similar structure in Pine Script:

//@version=5
indicator("Pivot Point Example", overlay = true)

// Define the `pivotPoint` UDT.
type Pivot
    int x
    float y
    string xloc = xloc.bar_time

// Example function to create and return a new pivotPoint object
method init_pivot(int x, float y) =>
    Pivot.new(x, y)

// Example usage
var Pivot myPivot = na
if (bar_index == 10)
    myPivot := init_pivot(bar_index, high)

Explanation

1. UDT Definition: The pivotPoint UDT is defined with fields x, y, and xloc, similar to the Python class's attributes. The xloc field has a default value of xloc.bar_time, mirroring the default parameter value in the Python class.

2. Object Creation: In Pine Script, objects of a UDT are created using the new() method. This example includes a custom function createPivotPoint that wraps the creation of a pivotPoint object, demonstrating how you might encapsulate object creation logic in a function, akin to using an __init__ method in Python.

3. Usage Example: The script demonstrates how to conditionally create a pivotPoint object at a specific bar index. This is a simplified example to show object creation and usage within Pine Script.

This example illustrates how to translate the concept of a Python class and its initialization to Pine Script's UDTs and functions. Pine Script's approach to object-oriented programming is more limited compared to Python, focusing on structuring data rather than behavior.