I know that the purpose of the page is to compare syntax of common lisp, racket, clojure, and emacs lisp. But some examples could be more idiomatic, for instance instead of

  (defun add (a &rest b)
    (if (null b)
        a
        (+ a (eval (cons '+ b)))))

One should avoid eval and use endp instead of null:

   (defun add (a &rest b)
        (if (endp b) a
            (apply #'add (+ a (first b)) (rest b))))

Notes on CL:

- why nothing on the "compiler" line? Everytime you load a snippet or a file with SBCL, it compiles it (to machine code). There's also compile-file.

- interpreter: likewise, all code is compiled by default with SBCL, not interpreted, even in the REPL. To use the interpreter, we must do this: https://github.com/lisp-tips/lisp-tips/issues/52

- command line program: the racket cell shows the use of -e (eval), the same can be done with any CL implementation.

- since the string split line introduces cl-ppcre, one could mention cl-str :D (plug) (much terser join, trim, concat etc)

- ah ok, for dates and times, flattening a list, hash-table literals… we need more libraries.

- more files operations: https://lispcookbook.github.io/cl-cookbook/files.html

- emacs buffers: now compare with Lem buffers 8-)

- posix-getenv: I'd rather use uiop:getenv (comes in implementations).

- uiop:*command-line-arguments*

- exit: uiop:quit

- uiop:run-program (sync) / launch-program (async)

- java interop: with LispWorks or ABCL (or other libraries)

my 2c

Perhaps related, I'm maintaining a "cheatsheet" to let Python programmers see what an Elisp equivalent to typical Python functions/methods are.

https://kickingvegas.github.io/elisp-for-python/

The page indicates that there is not function for documentation in common lisp, but

  (documentation 'documentation 'function)
      "Return the documentation string of Doc-Type for X, or NIL if none 
        exists. 
        System doc-types are VARIABLE, FUNCTION, STRUCTURE, TYPE, SETF, and T.

 Also http://rosettacode.org for computer tasks implemented in many computer languages to allow you compare syntax and code.

This is really neat.

Something I've been meaning to do is try putting together a cross-lisp package manager -- if only because it'd be fun. Maybe it would favor code that could be readily run or eval'd or maybe with some sort of clj/cljs type dynamic dispatch for anything implementation specific.

Great chrestomathy! I opened a PR for my lisp, Loon: https://github.com/clarkgrubb/hyperpolyglot/pull/139

Would be interesting to see how Jank is coming along in this space as well.

Clojure 1.6, Emacs 24.5... These are pretty old versions, at least of those.

As someone who's not a programmer but has beginner - medium python & C skills. I'm in middle of learning lisp (elisp to be precise) and it feels like reading poetry. It's a transcendent experience that's hard to explain. Such beautiful concepts. Everything flows in a way it doesn't in C based langs

Nice comparison.

But makes me think we'd be better off if we all just focused on a single one, and grew it, made it better. Not having 4 versions of something almost identical. Fragmentation can hurt adoption.

Emacs has cl-lib

https://www.gnu.org/software/emacs/manual/html_mono/cl.html