structural-search
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-ops.md- Security vulnerability detection./references/advanced-usage.md- YAML rules and tool integration./assets/rule-template.yaml- Starter template for custom rules
More from 0xdarkmatter/claude-mods
file-search
Modern file and content search using fd, ripgrep (rg), and fzf. Triggers on: fd, ripgrep, rg, find files, search code, fzf, fuzzy find, search codebase.
162container-orchestration
Docker and Kubernetes patterns. Triggers on: Dockerfile, docker-compose, kubernetes, k8s, helm, pod, deployment, service, ingress, container, image.
76python-pytest-patterns
pytest testing patterns for Python. Triggers on: pytest, fixture, mark, parametrize, mock, conftest, test coverage, unit test, integration test, pytest.raises.
60python-env
Fast Python environment management with uv (10-100x faster than pip). Triggers on: uv, venv, pip, pyproject, python environment, install package, dependencies.
50data-processing
Process JSON with jq and YAML/TOML with yq. Filter, transform, query structured data efficiently. Triggers on: parse JSON, extract from YAML, query config, Docker Compose, K8s manifests, GitHub Actions workflows, package.json, filter data.
50sqlite-ops
Patterns for SQLite databases in Python projects - state management, caching, and async operations. Triggers on: sqlite, sqlite3, aiosqlite, local database, database schema, migration, wal mode.
48