# Visitor

> **Class** in `langchain_core`

📖 [View in docs](https://reference.langchain.com/python/langchain-core/structured_query/Visitor)

Defines interface for IR translation using a visitor pattern.

## Signature

```python
Visitor()
```

## Extends

- `ABC`

## Properties

- `allowed_comparators`
- `allowed_operators`

## Methods

- [`visit_operation()`](https://reference.langchain.com/python/langchain-core/structured_query/Visitor/visit_operation)
- [`visit_comparison()`](https://reference.langchain.com/python/langchain-core/structured_query/Visitor/visit_comparison)
- [`visit_structured_query()`](https://reference.langchain.com/python/langchain-core/structured_query/Visitor/visit_structured_query)

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[View source on GitHub](https://github.com/langchain-ai/langchain/blob/fb6ab993a73180538f6cca876b3c85d46c08845f/libs/core/langchain_core/structured_query.py#L15)