---
name: grepai-languages
description: Supported programming languages in GrepAI. Use this skill to understand which languages can be indexed and traced.
---

# GrepAI Supported Languages

This skill covers the programming languages supported by GrepAI for indexing and call graph analysis.

## When to Use This Skill

- Checking if your language is supported
- Configuring language-specific settings
- Understanding trace capabilities per language
- Troubleshooting language-related issues

## Supported Languages Overview

GrepAI supports indexing for **all text-based files**, but has enhanced support for specific programming languages.

### Full Support (Index + Trace)

| Language | Extensions | Index | Trace |
|----------|------------|-------|-------|
| Go | `.go` | ✅ | ✅ |
| JavaScript | `.js`, `.jsx` | ✅ | ✅ |
| TypeScript | `.ts`, `.tsx` | ✅ | ✅ |
| Python | `.py` | ✅ | ✅ |
| PHP | `.php` | ✅ | ✅ |
| C | `.c`, `.h` | ✅ | ✅ |
| C++ | `.cpp`, `.hpp`, `.cc`, `.cxx`, `.hh` | ✅ | ✅ |
| Rust | `.rs` | ✅ | ✅ |
| Zig | `.zig` | ✅ | ✅ |
| C# | `.cs` | ✅ | ✅ |
| Java | `.java` | ✅ | ✅ |
| Pascal/Delphi | `.pas`, `.dpr` | ✅ | ✅ |

### Index Only (No Trace)

| Language | Extensions | Index | Trace |
|----------|------------|-------|-------|
| Ruby | `.rb` | ✅ | ❌ |
| Swift | `.swift` | ✅ | ❌ |
| Kotlin | `.kt`, `.kts` | ✅ | ❌ |
| Scala | `.scala` | ✅ | ❌ |
| Lua | `.lua` | ✅ | ❌ |
| Shell | `.sh`, `.bash`, `.zsh` | ✅ | ❌ |
| SQL | `.sql` | ✅ | ❌ |
| HTML | `.html`, `.htm` | ✅ | ❌ |
| CSS | `.css`, `.scss`, `.less` | ✅ | ❌ |
| Markdown | `.md`, `.mdx` | ✅ | ❌ |
| YAML | `.yaml`, `.yml` | ✅ | ❌ |
| JSON | `.json` | ✅ | ❌ |
| TOML | `.toml` | ✅ | ❌ |
| XML | `.xml` | ✅ | ❌ |

## Language Configuration

### Enabling/Disabling Languages for Trace

```yaml
# .grepai/config.yaml
trace:
  enabled_languages:
    - .go
    - .js
    - .ts
    - .jsx
    - .tsx
    - .py
    - .php
    - .rs
    - .c
    - .cpp
    - .cs
    - .java
```

### Excluding Certain Extensions

```yaml
trace:
  enabled_languages:
    - .go
    # Exclude JavaScript intentionally
    # - .js

  exclude_patterns:
    - "*_test.go"
    - "*.spec.ts"
```

## Language-Specific Tips

### Go

```yaml
trace:
  enabled_languages:
    - .go
  exclude_patterns:
    - "*_test.go"
    - "mock_*.go"
    - "*_mock.go"
```

**Trace accuracy:** Excellent. Go's explicit syntax makes tracing very reliable.

### JavaScript/TypeScript

```yaml
trace:
  enabled_languages:
    - .js
    - .jsx
    - .ts
    - .tsx
  exclude_patterns:
    - "*.test.js"
    - "*.spec.ts"
    - "*.d.ts"  # Type declarations
```

**Trace accuracy:** Good. Some dynamic patterns may be missed.

### Python

```yaml
trace:
  enabled_languages:
    - .py
  exclude_patterns:
    - "test_*.py"
    - "*_test.py"
    - "conftest.py"
```

**Trace accuracy:** Good. Dynamic imports and decorators may be missed.

### C/C++

```yaml
trace:
  enabled_languages:
    - .c
    - .h
    - .cpp
    - .hpp
    - .cc
    - .cxx
  exclude_patterns:
    - "*_test.cpp"
```

**Trace accuracy:** Good. Macros and templates may affect accuracy.

### Rust

```yaml
trace:
  enabled_languages:
    - .rs
  exclude_patterns:
    - "**/tests/**"
    - "**/benches/**"
```

**Trace accuracy:** Excellent. Rust's explicit syntax aids accurate tracing.

### PHP

```yaml
trace:
  enabled_languages:
    - .php
  exclude_patterns:
    - "*Test.php"
    - "**/tests/**"
```

**Trace accuracy:** Good. Magic methods may not be fully traced.

### Java

```yaml
trace:
  enabled_languages:
    - .java
  exclude_patterns:
    - "*Test.java"
    - "**/test/**"
```

**Trace accuracy:** Good. Reflection-based calls may be missed.

### C#

```yaml
trace:
  enabled_languages:
    - .cs
  exclude_patterns:
    - "*Tests.cs"
    - "**/Tests/**"
```

**Trace accuracy:** Good. Delegates and events may be partially traced.

## Multi-Language Projects

For projects with multiple languages:

```yaml
trace:
  enabled_languages:
    # Backend (Go)
    - .go
    # Frontend (TypeScript)
    - .ts
    - .tsx
    # Shared (SQL, etc.)
    - .sql  # Index only

  exclude_patterns:
    - "*_test.go"
    - "*.spec.ts"
```

## Index vs Trace Explained

### Index (Semantic Search)

- Works on **any text file**
- Code is chunked and embedded
- Enables semantic search
- No language-specific parsing required

### Trace (Call Graphs)

- Requires **language-specific parsing**
- Extracts function definitions and calls
- Builds caller/callee relationships
- Uses regex (fast) or tree-sitter (precise)

## Trace Modes by Language

| Language | Fast Mode | Precise Mode |
|----------|-----------|--------------|
| Go | ✅ | ✅ |
| JavaScript | ✅ | ✅ |
| TypeScript | ✅ | ✅ |
| Python | ✅ | ✅ |
| PHP | ✅ | ✅ |
| C/C++ | ✅ | ✅ |
| Rust | ✅ | ✅ |
| Zig | ✅ | ✅ |
| C# | ✅ | ✅ |
| Java | ✅ | ✅ |
| Pascal | ✅ | ⚠️ Limited |

## Adding Custom Extensions

If you have non-standard extensions, they'll be indexed but not traced:

```yaml
# Custom extension files will be indexed
ignore:
  # Only add patterns for files you DON'T want indexed
  - "*.generated.go"
```

## File Type Detection

GrepAI uses file extensions for detection. It does NOT use:
- Shebangs (`#!/usr/bin/env python`)
- File content analysis
- .editorconfig

## Unsupported Languages (Index Works, No Trace)

These languages can be indexed for semantic search but don't have trace support:

- Ruby
- Swift
- Kotlin
- Scala
- Elixir
- Clojure
- Haskell
- OCaml
- F#
- Erlang
- R
- Julia
- Perl
- Groovy

**Workaround:** Use semantic search to find code, then manually trace.

## Best Practices

1. **Enable only needed languages:** Faster trace building
2. **Exclude test files:** Cleaner trace results
3. **Use precise mode for accuracy:** When trace results seem incomplete
4. **Match your tech stack:** Configure based on your actual languages

## Checking Language Support

```bash
# Check what's being indexed
grepai status

# Will show file counts by type
```

## Common Issues

❌ **Problem:** Files not being indexed
✅ **Solution:** Check file isn't in ignore patterns

❌ **Problem:** Trace missing for language
✅ **Solution:** Ensure language is in `enabled_languages`

❌ **Problem:** Wrong language detected
✅ **Solution:** GrepAI uses extensions only; rename files if needed

## Output Format

Language support summary:

```
📚 GrepAI Language Support

Full Support (Index + Trace):
- Go (.go)
- JavaScript (.js, .jsx)
- TypeScript (.ts, .tsx)
- Python (.py)
- PHP (.php)
- C/C++ (.c, .cpp, .h, .hpp)
- Rust (.rs)
- Zig (.zig)
- C# (.cs)
- Java (.java)
- Pascal (.pas, .dpr)

Index Only (No Trace):
- Ruby, Swift, Kotlin, Scala
- Shell scripts, SQL, HTML, CSS
- Config files (YAML, JSON, TOML)
- Documentation (Markdown)

Your config enables trace for:
- .go, .js, .ts, .py
```