| name | structural-search |
| description | Search code by AST structure using ast-grep. Find semantic patterns like function calls, imports, class definitions instead of text patterns. Triggers on: find all calls to X, search for pattern, refactor usages, find where function is used, structural search, ast-grep, sg. |
| compatibility | Requires ast-grep (sg) CLI tool. Install: brew install ast-grep (macOS) or cargo install ast-grep (cross-platform). |
| allowed-tools | Bash |
Structural Search
Search code by its abstract syntax tree (AST) structure. Finds semantic patterns that regex cannot match reliably.
Tools
| Tool |
Command |
Use For |
| ast-grep |
sg -p 'pattern' |
AST-aware code search |
Pattern Syntax
| Pattern |
Matches |
Example |
$NAME |
Named identifier |
function $NAME() {} |
$_ |
Any single node |
console.log($_) |
$$$ |
Zero or more nodes |
function $_($$$) {} |
Top 10 Essential Patterns
# 1. Find console.log calls
sg -p 'console.log($_)'
# 2. Find React hooks
sg -p 'const [$_, $_] = useState($_)'
sg -p 'useEffect($_, [$$$])'
# 3. Find function definitions
sg -p 'function $NAME($$$) { $$$ }'
sg -p 'def $NAME($$$): $$$' --lang python
# 4. Find imports
sg -p 'import $_ from "$_"'
sg -p 'from $_ import $_' --lang python
# 5. Find async patterns
sg -p 'await $_'
sg -p 'async function $NAME($$$) { $$$ }'
# 6. Find error handling
sg -p 'try { $$$ } catch ($_) { $$$ }'
sg -p 'if err != nil { $$$ }' --lang go
# 7. Find potential issues
sg -p '$_ == $_' # == instead of ===
sg -p 'eval($_)' # Security risk
sg -p '$_.innerHTML = $_' # XSS vector
# 8. Preview refactoring
sg -p 'console.log($_)' -r 'logger.info($_)'
# 9. Apply refactoring
sg -p 'var $NAME = $_' -r 'const $NAME = $_' --rewrite
# 10. Search specific language
sg -p 'pattern' --lang typescript
Quick Reference
| Task |
Command |
| Find pattern |
sg -p 'pattern' |
| Specific language |
sg -p 'pattern' --lang python |
| Replace (preview) |
sg -p 'old' -r 'new' |
| Replace (apply) |
sg -p 'old' -r 'new' --rewrite |
| Show context |
sg -p 'pattern' -A 3 |
| JSON output |
sg -p 'pattern' --json |
| File list only |
sg -p 'pattern' -l |
| Count matches |
sg -p 'pattern' --count |
| Run YAML rules |
sg scan |
When to Use
- Finding all usages of a function/method
- Locating specific code patterns (hooks, API calls)
- Preparing for large-scale refactoring
- When regex would match false positives
- Detecting anti-patterns and security issues
- Creating custom linting rules
Additional Resources
For complete patterns, load:
./references/js-ts-patterns.md - JavaScript/TypeScript patterns
./references/python-patterns.md - Python patterns
./references/go-rust-patterns.md - Go and Rust patterns
./references/security-patterns.md - Security vulnerability detection
./references/advanced-usage.md - YAML rules and tool integration
./assets/rule-template.yaml - Starter template for custom rules