Lisp on MacOS

Background

Lisp is a programming language that’s been on my radar for a while, but I’ve never investigated until now. While browsing the web last night, I came across this Paul Graham article about the start of Viaweb and my curiousity was piqued.

This post is my attempt to consolidate my experience of getting a lisp development environment set up in July 2018.

Note: For the rest of this post, [~] $ is my terminal prompt, and * is the sbcl Common Lisp interpreter prompt

Lisp

SBCL (Steel Bank Common Lisp) appears to be the popular option for Common Lisp which, in turn, is the most popular open source Lisp dialect. This can be installed using homebrew:

$ brew install sbcl

To verify a Common Lisp interpreter is installed properly, open a terminal and type sbcl to enter the Common Lisp REPL:

```bash [~] $ sbcl –noinform * (+ 1 2 3)

6 * (quit) [~] $


# Editor

To my dismay, it seems as though the lisp programming environment is fundamentally tied to Emacs, an editor I've always eschewed. I can't even close Emacs without Ctrl-C. Visual Studio Code is my preferred tool.

I installed a GUI version of GNU Emacs from [Emacsforosx](https://emacsformacosx.com/) using homebrew:

bash [~] $ brew cask install emacs


Once brew finishes, this can be launched from the /Applications folder, using spotlight, or from the terminal with

bash [~] $ open -a /Applications/Emacs.app


# Editor package manager

Some searching led to [MELPA](https://melpa.org/#/getting-started) as the Emacs package manager I would have success with getting Slime - the Emacs Lisp helper package - installed.

I set up MELPA by following the installation instructions [here](https://melpa.org/#/getting-started):

bash [~] $ vi ~/.emacs


I pasted the MELPA initialization code below:

lisp (require ‘package) (let* ((no-ssl (and (memq system-type ‘(windows-nt ms-dos)) (not (gnutls-available-p)))) (proto (if no-ssl “http” “https”))) ;; Comment/uncomment these two lines to enable/disable MELPA and MELPA Stable as desired (add-to-list ‘package-archives (cons “melpa” (concat proto “://melpa.org/packages/“)) t) ;;(add-to-list ‘package-archives (cons “melpa-stable” (concat proto “://stable.melpa.org/packages/“)) t) (when (< emacs-major-version 24) ;; For important compatibility libraries like cl-lib (add-to-list ‘package-archives ‘(“gnu” . (concat proto “://elpa.gnu.org/packages/“))))) (package-initialize)


## Installing Slime

From the [Slime Introduction](https://common-lisp.net/project/slime/doc/html/Introduction.html#Introduction):

> SLIME is the “Superior Lisp Interaction Mode for Emacs.”
SLIME extends Emacs with support for interactive programming in Common Lisp.

To install this, I restarted Emacs.app, and then ran the package manager to install Slime:

(within Emacs.app) M-x package-install slime


I then added the Lisp interpreter I installed using Homebrew to my .emacs file:

(within iTerm.app) [~] $ echo “(setq inferior-lisp-program \“/usr/local/bin/sbcl\“)” >> ~/.emacs


## Success

At this point, everything is set up and ready to run! Common Lisp programming using SLIME can be initiated by opening Emacs.app and typing ```M-x slime <return>```

## Bonus round - Quicklisp

[Quicklisp](https://www.quicklisp.org/beta/) is the Common Lisp ~~package~~ library manager. It can be installed by [following the instructions at the Quicklisp website](https://www.quicklisp.org/beta/#Installation):

Download Quicklisp.lisp:

[~] $ curl -O https://beta.quicklisp.org/quicklisp.lisp


Install Quicklisp and specify a specific path to install quicklisp to (I don't want my home directory unnecessarily polluted, so I chose to install it to my :

[~] $ sbcl –noinform –load quicklisp.lisp

==== quicklisp quickstart 2015-01-28 loaded ====

To continue with installation, evaluate: (quicklisp-quickstart:install)

For installation options, evaluate: (quicklisp-quickstart:help)
  • (quicklisp-quickstart:install :path “~/.quicklisp”) …… ==== quicklisp installed ====

    To load a system, use: (ql:quickload “system-name”)

    To find systems, use: (ql:system-apropos “term”)

    To load Quicklisp every time you start Lisp, use: (ql:add-to-init-file)

    For more information, see http://www.quicklisp.org/beta/ *

    
    > **Note:** To force quicklisp to load at sbcl startup, execute the following post installation:
    
    
  • (ql:add-to-init-file)

    
    Verify that Quicklisp launches when the sbcl interperter starts by quitting sbcl, relaunching it, and typing ```(ql:help)```:
    
    

    bash

[~] $ sbcl –noinform * (ql:help)

“For help with Quicklisp, see http://www.quicklisp.org/beta/"


Verify that Emacs.app and the SLIME environment are correctly pulling in the Quicklisp configuration by launching Emacs.app, running ```M-x slime <return>``` and then entering:

  • (ql:help)

“For help with Quicklisp, see http://www.quicklisp.org/beta/"


# References

[Paul Graham - Lisp](http://www.paulgraham.com/lisp.html)  
[Paul Graham - Beating the Averages](http://www.paulgraham.com/avg.html)  
[Practical Common Lisp](http://www.gigamonkeys.com/book/)  
[SLIME User Manual](https://common-lisp.net/project/slime/doc/html/)  
[EmacsWiki - Emacs for MacOS](https://www.emacswiki.org/emacs/EmacsForMacOS#toc14)  
[Quicklisp](https://www.quicklisp.org/beta/)

## My .emacs file

After following the steps outlined above, this is what my .emacs file looks like (including two lines to change the meta key from alt/option to cmd on MacOS)

lisp (require ‘package) (let* ((no-ssl (and (memq system-type ‘(windows-nt ms-dos)) (not (gnutls-available-p)))) (proto (if no-ssl “http” “https”))) ;; Comment/uncomment these two lines to enable/disable MELPA and MELPA Stable as desired (add-to-list ‘package-archives (cons “melpa” (concat proto “://melpa.org/packages/“)) t) ;;(add-to-list ‘package-archives (cons “melpa-stable” (concat proto “://stable.melpa.org/packages/“)) t) (when (< emacs-major-version 24) ;; For important compatibility libraries like cl-lib (add-to-list ‘package-archives ‘(“gnu” . (concat proto “://elpa.gnu.org/packages/“))))) (package-initialize) (custom-set-variables ;; custom-set-variables was added by Custom. ;; If you edit it by hand, you could mess it up, so be careful. ;; Your init file should contain only one such instance. ;; If there is more than one, they won’t work right. ‘(package-selected-packages (quote (slime)))) (custom-set-faces ;; custom-set-faces was added by Custom. ;; If you edit it by hand, you could mess it up, so be careful. ;; Your init file should contain only one such instance. ;; If there is more than one, they won’t work right. ) (setq inferior-lisp-program “/usr/local/bin/sbcl”) (setq mac-option-modifier ‘super) (setq mac-command-modifier ‘meta) ```