Basic Syntax

; Variables
(def name "John")
(def age 30)

; Functions
(defn greet [name]
  (str "Hello, " name))

; Collections
(def numbers [1 2 3 4 5])
(def person {:name "John" :age 30})
(def unique-nums #{1 2 3})

; Map and filter
(map inc numbers)  ; [2 3 4 5 6]
(filter even? numbers)  ; (2 4)

; Threading macros
(->> numbers
     (map inc)
     (filter even?)
     (reduce +))

Data Structures

Concurrency

; Atoms for synchronous state
(def counter (atom 0))
(swap! counter inc)
@counter  ; Deref to get value

; Agents for asynchronous state
(def logger (agent []))
(send logger conj "Log entry")

; Refs for coordinated state (STM)
(def account1 (ref 100))
(def account2 (ref 200))
(dosync
  (alter account1 - 50)
  (alter account2 + 50))

Best Practices

• Prefer immutable data structures
• Use threading macros for readability
• Leverage REPL-driven development
• Use atoms for simple state management