Hello, World
(princ "Hello, World!\n")main.el
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main.el · output appears here
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Emacs Lisp 29.4Readymain.elLn 1, Col 1Spaces: 4UTF-8
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main.el · output appears here
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Emacs Lisp (Elisp) is the extension and scripting language at the heart of GNU Emacs. It is a dialect of Lisp with dynamic typing, an interactive read-eval-print loop, and direct access to the editor's buffers, windows, and commands. CompileBytes evaluates Elisp using Emacs 27.1, running scripts in batch mode so you can test functions, macros, and list manipulation without launching a graphical editor.
While Elisp was designed to customize Emacs, it is a general-purpose Lisp in its own right, with cons cells, closures (lexical binding), macros, and a large standard library. Programs are built from S-expressions, and side effects such as printing use functions like princ and message. In batch use, output written to standard output makes Elisp a viable way to explore functional and symbolic programming.
main.el is the entry point for each run.
Use the Input panel to pipe standard input to your program when it needs data.
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(princ "Hello, World!\n")(defun square (n)
(* n n))
(princ (square 7))
(terpri)(dolist (x '(1 2 3 4))
(princ (* x x))
(princ " "))
(terpri)(defun fact (n)
(if (<= n 1) 1
(* n (fact (1- n)))))
(princ (fact 5))
(terpri)(dotimes (i 5)
(princ i)
(princ " "))
(terpri)(let ((nums '(1 2 3 4 5)))
(princ (mapcar (lambda (x) (* x x)) nums))
(terpri))(defun sign (x)
(cond ((> x 0) "positive")
((< x 0) "negative")
(t "zero")))
(princ (sign -4))
(terpri)(let ((name "Ada") (age 36))
(princ (format "%s is %d\n" name age)))(let ((n 5))
(while (> n 0)
(princ n)
(princ " ")
(setq n (1- n))))
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Emacs Lisp is one of 46 single-file compiler scratchpads. Each run submits only main.el; 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.
Download file exports the active Emacs Lisp source file.