REPL駆動開発のワークフロー

What is a REPL?

The REPL Cycle

Launching Your REPL

Your First REPL Interaction

(ns coddykit.core
  (:gen-class))

(defn -main
  "Simulates basic REPL evaluation."
  [& args]
  (println "Result of (+ 10 5):" (+ 10 5))
  (println "Result of (str \"Hello\" \" \" \"REPL!\") :" (str "Hello" " " "REPL!"))
)

Storing Values with `def`

(ns coddykit.core
  (:gen-class))

(defn -main
  "Demonstrates 'def' in a REPL-like context."
  [& args]
  (def my-favorite-number 42)
  (println "My favorite number is:" my-favorite-number)

  (def greeting-message "Welcome to Clojure!")
  (println greeting-message)
)

Creating Functions with `defn`

(ns coddykit.core
  (:gen-class))

(defn add-two [num]
  (+ num 2))

(defn -main
  "Demonstrates 'defn' and function calling."
  [& args]
  (println "5 plus 2 is:" (add-two 5))
  (println "10 plus 2 is:" (add-two 10))
)

Building Incrementally

Edit, Evaluate, Repeat

(ns coddykit.core
  (:gen-class))

(defn calculate-sum [a b]
  (println "Calculating sum...")
  (+ a b))

(defn -main
  "Illustrates REPL's immediate feedback potential."
  [& args]
  (println "First call:" (calculate-sum 7 3))
  ; Imagine you redefined 'calculate-sum' to multiply
  ; and then evaluated it again in the REPL.
  ; The next call would use the new definition!
  (println "Second call:" (calculate-sum 2 8))
)

Why REPL-Driven Development?

REPL Quick Check

REPL Power Up!