Welcome back! You've been learning how to define functions, handle multiple arity, and work with variadic functions in Clojure. Now, you're ready to explore an important aspect of writing well-documented and maintainable code: function meta information and documentation. This lesson will show you how to add meaningful descriptions and metadata to your functions, making your code easier to understand and collaborate on.

In this lesson, we'll focus on two key aspects:

• Docstrings: You'll learn how to add inline documentation to your functions, helping future you (and others) understand what the function does.
• Metadata Maps: You'll discover how to enrich your functions with additional metadata such as version information, author information, and more.

These techniques are fundamental for writing clear and maintainable Clojure code. Here’s a quick overview with examples:

Docstrings are a great way to add brief descriptions directly inside your functions:

Clojure
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1(defn calculate-hero-damage
2  "Calculates hero's damage output."
3  [base-damage critical-multiplier]
4  (* base-damage critical-multiplier))

Metadata maps allow you to provide more detailed information about functions:

Clojure
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1(defn ^{:doc "Calculates the total ammunition cost given cost per unit and quantity."
2        :added "1.0"
3        :author "Cosmo"}
4  total-ammo-cost [ammo-cost number-of-units]
5  (* ammo-cost number-of-units))

Adding documentation and metadata to your functions makes your code more readable and maintainable. It helps other developers (and your future self) understand the purpose and usage of each function without diving deep into the implementation. Properly documented code is crucial for effective collaboration, debugging, and future enhancements.

Ready to make your Clojure functions more informative and easier to maintain? Let's dive into the practice section and start enhancing our functions with meaningful documentation and metadata.