How to enable rainbow parentheses in SLIME?

Question

I am an Emacs and Common Lisp novice. I have successfully installed SLIME in my Emacs, but I noticed it does not have rainbow parentheses (which comes as a surprise). How do I enable this feature? Thanks in advance.

Answer 1

There's a Rainbow Delimiters mode over on emacswiki which might suit you - otherwise there's a bunch of other parenthesis appearance packages there as well.

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Update: This worked for me.
This is probably still not as novice-friendly as it could be. I've had 20 years of on-and-off use to help me forget what being a total Emacs novice is like...

First, make sure there's an .emacs file in your home directory. C-x C-f [visit-buffer] followed by ~/.emacs and Enter should do the trick.

You also need a directory to save your elisp files in.
"~/.emacs.d/" is usually on the load-path, so using that is the easiest way to get started.
Create it if it doesn't exist.

Next, download rainbow-delimiters.el. It should go into your elisp folder from the previous step.
Type M-x byte-compile-file, followed by Return, then the path to your rainbow-delimiters.el (this step is only for efficiency).

Now enter the following in your .emacs:

(require 'rainbow-delimiters)
(add-hook 'slime-repl-mode-hook 'rainbow-delimiters-mode)

and save (C-x C-s) and restart.

(A "mode hook" is a function (or rather list of functions) that is called when Emacs switches to a specific mode.).

If you don't want to restart Emacs just to try it, you can position the cursor at the end of each expression and type C-x C-e [eval-last-sexp] (this also works in the interactive "*scratch*" buffer).

Starting slime with M-x slime after this gave me coloured parentheses.

The colour scheme is customizable; the easiest way of finding the options is M-x customize-apropos (hit Return), type rainbow (hit Return).

HTH.

Oh, and look through the built-in tutorial (C-h t) if you haven't already. Emacs has a slightly peculiar vocabulary, so reading the documentation (C-h i) now and then is good, and there's plenty of "oh, it can do that" moments in there.