# Visitor Pattern

## Overview

The Visitor Pattern is a behavioral design pattern that allows you to add further operations to objects without modifying their structure. It achieves this by separating the algorithm from the objects on which it operates. In AI systems, this pattern is particularly useful when different operations, such as model explanations, evaluations, or transformations, need to be applied to models or datasets without altering their core structure.

## Benefits

- **Separation of Concerns:** The Visitor Pattern separates the operations, such as explanation or evaluation methods, from the models they operate on. This separation makes the system more modular, allowing AI practitioners to add new analytical operations without modifying the underlying model structure.
- **Extensibility:** The pattern makes it easy to introduce new operations, like different explanation techniques or evaluation metrics, to existing models without needing to change the model classes themselves. This is particularly valuable in AI, where the need to apply diverse techniques to models arises frequently.
- **Centralized Logic:** By centralizing the logic of operations in visitor classes, the Visitor Pattern simplifies the code within AI models and makes it easier to manage, extend, and debug complex AI workflows.

## Use Cases

- **Model Explanation Techniques:** The Visitor Pattern can be used to apply different explanation techniques, such as SHAP (SHapley Additive exPlanations) or LIME (Local Interpretable Model-agnostic Explanations), to machine learning models without modifying the models’ internal structure.
- **Model Evaluation:** It can facilitate applying various evaluation metrics or algorithms to models, such as cross-validation, confusion matrix analysis, or performance scoring, while keeping the model code clean and focused on prediction tasks.
- **Data Transformation:** In AI pipelines, the pattern can be used to apply different data transformations or feature engineering steps to datasets, allowing for flexible and reusable processing logic.

## Pattern Illustration

<div align="center">
  <img src="./../../../img/13_visitor.png" alt="Visitor Pattern" style="width: 75%; height: auto;">
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