Clojure is a Lisp on the JVM. Code is written as lists: (println "hello") calls println with one argument. The function always comes first inside the parentheses.
Clojure · Lesson 1 · On the house
Hello Clojure
println, prefix calls, comments, and running a file or REPL. Lesson 1 is free — on the house.
Lessons · Clojure · Lesson 1 of 10 · On the house
Hello Clojure
println, prefix calls, comments, and running a file or REPL.
Arithmetic is prefix too: (+ 1 2 3) is 6, and (* 2 (+ 3 4)) is 14. Operators take any number of arguments, so (< 1 2 3) checks the whole chain.
Comments start with ;. (comment ...) wraps code you want to keep but not run, and #_ skips the next form.
Run a file with the Clojure CLI, clj -M hello.clj, or with Babashka, bb hello.clj, which starts in milliseconds. Type clj alone to get a REPL, where you evaluate one form at a time.
Misses: writing println("hi") with the function outside the parens, or using // comments.
hello
; hello.clj
(println "hello")
(println (+ 1 2 3))
(println (* 2 (+ 3 4)))
(println (< 1 2 3))
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