Hello World
(println "Hello, World!")main.clj
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Clojure 1.11.1Readymain.cljLn 1, Col 1Spaces: 4UTF-8
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main.clj · output appears here
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Clojure is a dynamic, functional dialect of Lisp created by Rich Hickey and first released in 2007. It runs on the Java Virtual Machine, compiling to JVM bytecode and offering seamless interoperability with Java libraries. Clojure emphasizes immutability, persistent data structures, and a code-as-data (homoiconic) philosophy, making it well suited for concurrent and data-oriented programming.
Clojure favors pure functions and provides robust concurrency primitives such as atoms, refs with software transactional memory, and agents. It is used for web services, data processing, and analytics, and its REPL-driven workflow encourages interactive development. ClojureScript targets JavaScript, extending the language to the browser and Node.js while sharing the same core semantics.
main.clj is the entry point for each run.
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(println "Hello, World!")(let [name (read-line)]
(println (str "Hello, " name "!")))(def nums [1 2 3 4 5])
(println (map #(* % %) nums))(defn add [a b]
(+ a b))
(println (add 2 3))(def person {:name "Alice" :age 30})
(println (:name person))
(def updated (assoc person :age 31))
(println updated)(def nums (range 1 11))
(println (->> nums
(filter even?)
(map #(* % %))
(reduce +)))(defn factorial [n]
(loop [acc 1 i n]
(if (<= i 1)
acc
(recur (* acc i) (dec i)))))
(println (factorial 5))(def counter (atom 0))
(swap! counter inc)
(swap! counter + 10)
(println @counter)(let [[a b & rest] [1 2 3 4 5]
{:keys [name age]} {:name "Bob" :age 25}]
(println a b rest)
(println name age))(def evens (filter even? (range)))
(println (take 5 evens))
(println (->> (range 1 6)
(map inc)
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Clojure is one of 46 single-file compiler scratchpads. Each run submits only main.clj; local sibling-file imports are not enabled.
Linked-project languages (23): Node.js, TypeScript, Deno, Python, C, Go, Dart, Swift, Rust, Ruby, PHP, Java, Kotlin, C++, C#, Nim, Crystal, Haxe, Zig, Scala, D, Bun, Objective-C.
Single-file scratchpads (46): Matplotlib, NumPy, pandas, Haskell, Clojure, Perl, Lua, Tcl, jq, Raku, Elixir, Bash, Zsh, Nushell, R, Assembly (NASM), Julia, Octave, Groovy, PowerShell, Visual Basic .NET, Odin, Pascal, Lisp, Erlang, CoffeeScript, COBOL, BASIC, V, Racket, OCaml, Prolog, AWK, Emacs Lisp, Emojicode, Forth, F#, Fortran, Assembly (NASM64), Solidity, Mojo, Ada, WASM (WAT), Gleam, Shell Script (sh), Scheme.
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