**Deep dive into AST patterns andAST-Grep rules**

**Deep dive into AST patterns andast-grep rules**

- AST patterns[wikipedia](https://en.wikipedia.org/wiki/Abstract_syntax_tree)

-AST-grep[official documentation](https://ast-grep.github.io/guide/rule-config.html) for detailed guides.

-ast-grep[official documentation](https://ast-grep.github.io/guide/rule-config.html) for detailed guides.

This section explains how to add custom code review instructions usingAST-Grep rules.AST-Grep is a tool used for searching code using abstract syntax trees (AST) patterns.

This section explains how to add custom code review instructions usingast-grep rules.ast-grep is a tool used for searching code using abstract syntax trees (AST) patterns.

By default, you can addAST-Grep rules by following these steps:

By default, you can addast-grep rules by following these steps:

1. Create a folder that keeps all the ast-grep rules in your project directory.

2. Add individual`.yaml` files for eachAST-Grep rule within the newly created folder.

3. Ensure that each`.yaml` file contains the necessaryAST-Grep rule configurations.

2. Add individual`.yaml` files for eachast-grep rule within the newly created folder.

3. Ensure that each`.yaml` file contains the necessaryast-grep rule configurations.

4. Ensure that all rules contains a`message` property, that will be used in the review process.

5. Add the rules folder to the`.coderabbit.yml` file under`tools.ast-grep` configuration.

-JavaScript

-Typescript

-Python

-C

Below are examples ofAST-Grep rules in different languages:

Below are examples ofast-grep rules in different languages: