Unleashing the Power of Automated Documentation and Code Generation

Table of Contents

File Headers and Metadata

File headers provide essential context about source code ownership, licensing, and purpose.

License Headers

Standard Apache 2.0 header:

/**
 * Copyright 2025 Jason Walsh
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 */

Auto-generated Headers

Headers can include metadata for build systems and generators:

# -*- coding: utf-8 -*-
"""
Module: data_processor.py
Auto-generated: 2025-12-22T10:30:00Z
Generator: CodeGen v2.1.0
"""

JSDoc Documentation

Syntax and Tags

JSDoc uses block comments with @ tags for comprehensive API documentation:

/**
 * Calculates the total price with tax and discount.
 *
 * @param {number} price - The base price of the item
 * @param {number} taxRate - Tax rate as decimal (e.g., 0.08 for 8%)
 * @param {number} [discount=0] - Optional discount percentage
 * @returns {number} The final calculated price
 * @throws {Error} When price or taxRate is negative
 * @example
 * calculateTotal(100, 0.08, 10)
 * // returns 97.2
 */
function calculateTotal(price, taxRate, discount = 0) {
  if (price < 0 || taxRate < 0) {
    throw new Error('Price and tax rate must be non-negative');
  }
  return price * (1 + taxRate) * (1 - discount / 100);
}

Type Annotations

Modern JSDoc supports TypeScript-style type definitions:

/**
 * @typedef {Object} User
 * @property {string} id - Unique user identifier
 * @property {string} email - User email address
 * @property {string[]} roles - Array of user roles
 * @property {Date} createdAt - Account creation timestamp
 */

/**
 * @param {User} user - The user object
 * @returns {boolean} True if user is admin
 */
function isAdmin(user) {
  return user.roles.includes('admin');
}

Modern Documentation Tools

TypeDoc for TypeScript

TypeDoc generates HTML documentation from TypeScript source code:

/**
 * Generic repository for database operations.
 *
 * @typeParam T - The entity type managed by this repository
 */
export class Repository<T extends { id: string }> {
  /**
   * Finds an entity by its unique identifier.
   *
   * @param id - The entity ID to search for
   * @returns Promise resolving to the entity or null
   */
  async findById(id: string): Promise<T | null> {
    // Implementation
    return null;
  }
}

Configuration in typedoc.json:

{
  "entryPoints": ["src/index.ts"],
  "out": "docs",
  "theme": "default",
  "excludePrivate": true
}

Sphinx for Python

Sphinx uses reStructuredText and supports multiple output formats:

def process_data(items, threshold=0.5, normalize=True):
    """Process a collection of data items with optional normalization.

    Args:
        items (List[float]): Input data values to process
        threshold (float, optional): Filtering threshold. Defaults to 0.5.
        normalize (bool, optional): Apply normalization. Defaults to True.

    Returns:
        List[float]: Processed data values

    Raises:
        ValueError: If items list is empty
        TypeError: If items contains non-numeric values

    Example:
        >>> process_data([1.0, 2.0, 3.0], threshold=1.5)
        [2.0, 3.0]
    """
    if not items:
        raise ValueError("Items list cannot be empty")

    filtered = [x for x in items if x >= threshold]
    return [x / max(filtered) for x in filtered] if normalize else filtered

Rustdoc for Rust

Rustdoc uses markdown-flavored documentation comments:

/// A thread-safe cache with TTL support.
///
/// # Examples
///
/// ```
/// use mylib::Cache;
///
/// let cache = Cache::new(100);
/// cache.insert("key", "value", Duration::from_secs(60));
/// assert_eq!(cache.get("key"), Some("value"));
/// ```
///
/// # Panics
///
/// Panics if capacity is zero.
pub struct Cache<K, V> {
    capacity: usize,
    // fields...
}

impl<K, V> Cache<K, V> {
    /// Creates a new cache with the specified capacity.
    ///
    /// # Arguments
    ///
    /// * `capacity` - Maximum number of items to store
    pub fn new(capacity: usize) -> Self {
        assert!(capacity > 0, "Capacity must be greater than zero");
        Cache { capacity }
    }
}

AI-Assisted Documentation (LLMs)

Using language models to generate documentation from code:

# Example using OpenAI API
import openai

def generate_docstring(function_code):
    """Generate docstring using LLM."""
    prompt = f"""Generate a comprehensive Python docstring for this function:

{function_code}

Include Args, Returns, Raises, and Example sections."""

    response = openai.ChatCompletion.create(
        model="gpt-4",
        messages=[{"role": "user", "content": prompt}]
    )
    return response.choices[0].message.content

Code Generation

AST-Based Generation

Using Abstract Syntax Trees to generate code:

import ast

def generate_test_skeleton(source_file):
    """Generate test stubs from source code using AST."""
    with open(source_file) as f:
        tree = ast.parse(f.read())

    tests = []
    for node in ast.walk(tree):
        if isinstance(node, ast.FunctionDef):
            test_name = f"test_{node.name}"
            tests.append(f"""
def {test_name}():
    \"\"\"Test for {node.name}.\"\"\"
    # TODO: Implement test
    pass
""")
    return "\n".join(tests)

Template-Based Approaches

Using templates for consistent code generation:

from jinja2 import Template

crud_template = Template("""
class {{ model_name }}Repository:
    def create(self, {{ model_var }}: {{ model_name }}) -> {{ model_name }}:
        # Implementation
        pass

    def read(self, id: str) -> Optional[{{ model_name }}]:
        # Implementation
        pass

    def update(self, {{ model_var }}: {{ model_name }}) -> {{ model_name }}:
        # Implementation
        pass

    def delete(self, id: str) -> bool:
        # Implementation
        pass
""")

# Generate repository class
code = crud_template.render(model_name="User", model_var="user")

LLM Code Generation

Modern approach using language models for code generation:

def generate_boilerplate(description):
    """Generate code from natural language description."""
    system_prompt = """You are a code generator. Generate clean,
    well-documented code based on user requirements."""

    # Example with Claude API
    import anthropic

    client = anthropic.Anthropic()
    message = client.messages.create(
        model="claude-opus-4-5-20251101",
        max_tokens=2048,
        messages=[{
            "role": "user",
            "content": f"Generate Python code: {description}"
        }]
    )
    return message.content[0].text

# Usage
code = generate_boilerplate(
    "Create a REST API endpoint for user authentication with JWT"
)

Google Closure Compiler Integration

The Closure Compiler uses JSDoc annotations for type checking and optimization:

/**
 * @constructor
 * @param {string} name
 * @param {number} age
 */
function Person(name, age) {
  /** @type {string} */
  this.name = name;

  /** @type {number} */
  this.age = age;
}

/**
 * @return {string}
 */
Person.prototype.greet = function() {
  return 'Hello, I am ' + this.name;
};

Author: Jason Walsh

j@wal.sh

Last Updated: 2025-12-22 23:11:07

build: 2025-12-29 20:03 | sha: 3c17632