# AST-GREP

> Find Code by Syntax

ast-grep(sg) is a fast and polyglot tool for code structural search, lint, rewriting at large scale.

## Table of Contents

### Guide

- [Quick Start](/guide/quick-start.md): Learn how to install ast-grep and use it to quickly find and refactor code in your codebase. This powerful tool can help you save time and improve the quality of your code.
- [Pattern Syntax](/guide/pattern-syntax.md)
- [Rule Essentials](/guide/rule-config.md)
- [Scan Your Project!](/guide/scan-project.md)
- [Rewrite Code](/guide/rewrite-code.md)
- [Command Line Tooling Overview](/guide/tooling-overview.md)
- [API Usage](/guide/api-usage.md)

#### Rule Essentials

- [Atomic Rule](/guide/rule-config/atomic-rule.md)
- [Relational Rules](/guide/rule-config/relational-rule.md)
- [Composite Rule](/guide/rule-config/composite-rule.md)
- [Reusing Rule as Utility](/guide/rule-config/utility-rule.md)

#### Project Setup

- [Project Configuration](/guide/project/project-config.md)
- [Lint Rule](/guide/project/lint-rule.md)
- [Test Your Rule](/guide/test-rule.md)
- [Handle Error Reports](/guide/project/severity.md)

#### Rewrite Code

- [`transform` Code in Rewrite](/guide/rewrite/transform.md)
- [Rewriter in Fix](/guide/rewrite/rewriter.md)

#### Tooling Overview

- [Editor Integration](/guide/tools/editors.md)
- [JSON Mode](/guide/tools/json.md)

#### API Usage

- [JavaScript API](/guide/api-usage/js-api.md)
- [Python API](/guide/api-usage/py-api.md)
- [Performance Tip for napi usage](/guide/api-usage/performance-tip.md)

### Examples

- [C](/catalog/c.md)
- [Cpp](/catalog/cpp.md)
- [Go](/catalog/go.md)
- [HTML](/catalog/html.md)
- [Java](/catalog/java.md)
- [Kotlin](/catalog/kotlin.md)
- [Python](/catalog/python.md)
- [Ruby](/catalog/ruby.md)
- [Rust](/catalog/rust.md)
- [TypeScript](/catalog/typescript.md)
- [TSX](/catalog/tsx.md)
- [YAML](/catalog/yaml.md)

### Cheat Sheet

- [Rule Cheat Sheet](/cheatsheet/rule.md)
- [Config Cheat Sheet](/cheatsheet/yaml.md)

### Reference

- [Command Line Reference](/reference/cli.md)
- [`sgconfig.yml` Reference](/reference/sgconfig.md)
- [Configuration Reference](/reference/yaml.md)
- [Rule Object Reference](/reference/rule.md)
- [API Reference](/reference/api.md)
- [List of Languages with Built-in Support](/reference/languages.md)
- [ast-grep Playground Manual](/reference/playground.md)

#### Command Line Interface

- [`ast-grep run`](/reference/cli/run.md)
- [`ast-grep scan`](/reference/cli/scan.md)
- [`ast-grep test`](/reference/cli/test.md)
- [`ast-grep new`](/reference/cli/new.md)

#### Rule Config

- [Fix](/reference/yaml/fix.md)
- [Transformation Object](/reference/yaml/transformation.md)
- [Rewriter](/reference/yaml/rewriter.md)

### Advanced Topics

- [Using ast-grep with AI Tools](/advanced/prompting.md)
- [Frequently Asked Questions](/advanced/faq.md)
- [How ast-grep Works: A bird's-eye view](/advanced/how-ast-grep-works.md)
- [Custom Language Support](/advanced/custom-language.md)
- [Search Multi-language Documents in ast-grep](/advanced/language-injection.md)
- [Comparison With Other Frameworks](/advanced/tool-comparison.md)

#### How ast-grep Works

- [Core Concepts in ast-grep's Pattern](/advanced/core-concepts.md)
- [Deep Dive into ast-grep's Pattern Syntax](/advanced/pattern-parse.md)
- [Deep Dive into ast-grep's Match Algorithm](/advanced/match-algorithm.md)
- [Find & Patch: A Novel Functional Programming like Code Rewrite Scheme](/advanced/find-n-patch.md)

### Contributing

- [Contributing](/contributing/how-to.md)
- [Development Guide](/contributing/development.md)
- [Add New Language to ast-grep](/contributing/add-lang.md)

### Links

- [Playground](/playground.md): ast-grep playground is an online tool that lets you explore AST, debug custom lint rules, and inspect code rewriting with instant feedback.

### Other

- [define a rewriter to remove the await keyword](/catalog/python/remove-async-await.md)
- [efine test(x) (2*x)](/catalog/c/match-function-call.md)
- [ensure it only matches modal/tooltip but not tag](/catalog/html/upgrade-ant-design-vue.md)
- [find the barrel import statement](/catalog/typescript/speed-up-barrel-import.md)
- [find-all-imports-and-identifiers.yaml](/catalog/typescript/find-import-identifiers.md)
- [or without fixer](/catalog/rule-template.md)
- [Pattern 1: Rails.root.join with variable](/catalog/ruby/detect-path-traversal.md)
- [rewrite Optional[T] to T | None](/catalog/python/recursive-rewrite-type.md)
- [Should not be transformed](/catalog/python/rewrite-sqlalchemy-mapped-column.md)
- [TODO:](/links/roadmap.md)
- [Untitled](/catalog/c/rewrite-method-to-function-call.md)
- [Untitled](/catalog/c/yoda-condition.md)
- [Untitled](/catalog/cpp/find-struct-inheritance.md)
- [Untitled](/catalog/cpp/fix-format-vuln.md)
- [Untitled](/catalog/go/defer-func-call-antipattern.md)
- [Untitled](/catalog/go/find-func-declaration-with-prefix.md)
- [Untitled](/catalog/go/match-function-call.md)
- [Untitled](/catalog/go/unmarshal-tag-is-dash.md)
- [Untitled](/catalog/go/match-package-import.md)
- [Untitled](/catalog/html/extract-i18n-key.md)
- [Untitled](/catalog/java/find-field-with-type.md)
- [Untitled](/catalog/java/no-unused-vars.md)
- [Untitled](/catalog/kotlin/ensure-clean-architecture.md)
- [Untitled](/catalog/python/optional-to-none-union.md)
- [Untitled](/catalog/python/prefer-generator-expressions.md)
- [Untitled](/catalog/python/migrate-openai-sdk.md)
- [Untitled](/catalog/python/refactor-pytest-fixtures.md)
- [Untitled](/catalog/python/use-walrus-operator-in-if.md)
- [Untitled](/catalog/ruby/migrate-action-filter.md)
- [Untitled](/catalog/ruby/prefer-symbol-over-proc.md)
- [Untitled](/catalog/rust/avoid-duplicated-exports.md)
- [Untitled](/catalog/rust/boshen-footgun.md)
- [Untitled](/catalog/rust/get-digit-count-in-usize.md)
- [Untitled](/catalog/rust/redundant-unsafe-function.md)
- [Untitled](/catalog/rust/rewrite-indoc-macro.md)
- [Untitled](/catalog/tsx/avoid-jsx-short-circuit.md)
- [Untitled](/catalog/tsx/avoid-nested-links.md)
- [Untitled](/catalog/tsx/redundant-usestate-type.md)
- [Untitled](/catalog/tsx/rename-svg-attribute.md)
- [Untitled](/catalog/tsx/reverse-react-compiler.md)
- [Untitled](/catalog/tsx/rewrite-mobx-component.md)
- [Untitled](/catalog/tsx/unnecessary-react-hook.md)
- [Untitled](/catalog/typescript/find-import-file-without-extension.md)
- [Untitled](/catalog/typescript/find-import-usage.md)
- [Untitled](/catalog/typescript/migrate-xstate-v5.md)
- [Untitled](/catalog/typescript/missing-component-decorator.md)
- [Untitled](/catalog/typescript/no-console-except-catch.md)
- [Untitled](/catalog/typescript/no-await-in-promise-all.md)
- [Untitled](/catalog/yaml/find-key-value.md)
- [Untitled](/catalog/typescript/switch-from-should-to-expect.md)
- [Untitled](/catalog/typescript/use-logical-assignment.md)