Explain

/explain - Deep Code Explanation

Provide detailed explanations of code, concepts, or patterns.

Usage

/explain path/to/file.py         # Explain entire file
/explain function_name           # Explain specific function
/explain "async/await"           # Explain concept
/explain --level beginner        # Adjust explanation depth

What This Skill Does

1. Parse Code - Understand structure and flow
2. Identify Concepts - Patterns, idioms, techniques
3. Explain Purpose - What and why
4. Show Flow - Step-by-step execution
5. Provide Context - When to use, alternatives

Explanation Format

# Explanation: [Topic]

## Overview
Brief summary of what this code/concept does.

## Purpose
Why does this exist? What problem does it solve?

## How It Works

### Step-by-Step
1. **Step 1**: Description
   ```python
   relevant_code_snippet()

2. Step 2: Description

   next_snippet()
   

Visual Flow

Input → Process A → Process B → Output
         ↓
    Side Effect

Key Concepts

Concept 1: [Name]

Explanation of underlying concept.

Concept 2: [Name]

Explanation of another concept.

Example Usage

# Simple example
result = function(input)

# Advanced example with options
result = function(
    input,
    option1=True,
    option2="value"
)

Common Pitfalls

• Pitfall 1: What goes wrong and how to avoid it
• Pitfall 2: Another common mistake

Alternatives

• Alternative 1: When to use this instead
• Alternative 2: Trade-offs of this approach

Related Concepts

• Link to related topic 1
• Link to related topic 2

Further Reading

• Resource 1
• Resource 2

## Explanation Levels

### Beginner
- Simple vocabulary
- More analogies
- Step-by-step detail
- Avoid jargon
- More code comments

### Intermediate
- Assume basic knowledge
- Focus on patterns
- Discuss trade-offs
- Include edge cases

### Advanced
- Technical depth
- Performance implications
- Implementation details
- Comparison with alternatives

## Example Explanations

### Explaining Decorators
```markdown
## Overview
A decorator is a function that wraps another function to extend its behavior
without modifying the original code.

## How It Works
```python
@log_calls
def greet(name):
    return f"Hello, {name}"

Is equivalent to:

def greet(name):
    return f"Hello, {name}"

greet = log_calls(greet)  # Wrapping happens here

The @ syntax is just syntactic sugar for this wrapping pattern.

Step-by-Step Execution

1. Python sees @log_calls above greet
2. Python defines greet as normal
3. Python calls log_calls(greet)
4. The result replaces greet
5. When you call greet("World"), you're calling the wrapped version

### Explaining Async/Await
```markdown
## Overview
`async/await` lets you write non-blocking code that looks synchronous.

## The Problem
```python
# Blocking - waits doing nothing
data1 = fetch_from_api()  # 2 seconds
data2 = fetch_from_db()   # 2 seconds
# Total: 4 seconds

The Solution

# Non-blocking - runs concurrently
data1, data2 = await asyncio.gather(
    fetch_from_api(),  # 2 seconds
    fetch_from_db()    # 2 seconds
)
# Total: ~2 seconds

While waiting for I/O, Python can do other work.

## Instructions for Claude

When /explain is invoked:

1. **Identify target** - Code, function, or concept
2. **Determine level** - Beginner, intermediate, advanced
3. **Read context** - Surrounding code, usage
4. **Structure explanation** - Overview → details → examples
5. **Use analogies** - For complex concepts
6. **Show execution** - Step-by-step flow
7. **Include examples** - Practical usage
8. **Note pitfalls** - Common mistakes
9. **Suggest alternatives** - When relevant