An overview of how to quickly set up a development environment and get started with Common Lisp. Install a lisp, add some libraries, write some code!

Getting started developing with Common Lisp is tricky, and probably one of the reasons people are turned off by the language in general. Which is a shame really. It’s like being put off desert because there are too many choices on the menu (the correct choice is always tiramisu).

Why would I even bother?

The multiple very good reasons to use Common Lisp are well described in several other web-sites, so I won’t bother. Actually, here’s just one – it’s more fun than Minecraft.

Anyway, this website is about getting stuff done, so here are the main components required to get up and running with Lisp:

  • Install a Common Lisp implementation
  • Install Quicklisp and get some useful libraries
  • Install a development environment

The entire process should take less than 5 minutes.

Note: If all you really want to do is write some Lisp now, then check out Portacle, which packages up a CL development environment into one download. Super handy, great if you just want to get into Lisp quickly. However if you want to set up a more permanent/configurable development environment, you’ll want to read on…

Installing Lisp

Let’s answer the immediate practical question:

How do I even install Lisp!?

And in most cases, the answer is this:

Google “Steel Bank Common Lisp”, and install it. Now.

Or just click this link to go straight to the download page. Or use your favourite package manager, which will probably have an sbcl package available.

There you go, you’ve installed Common Lisp (the SBCL implementation, to be precise - there are others). Fire it up in a terminal:

$ sbcl
This is SBCL 1.3.12, an implementation of ANSI Common Lisp.
More information about SBCL is available at <http://www.sbcl.org/>.

SBCL is free software, provided as is, with absolutely no warranty.
It is mostly in the public domain; some portions are provided under
BSD-style licenses.  See the CREDITS and COPYING files in the
distribution for more information.
*

You’re now sitting in a Read-Eval-Print-Loop (REPL), a fully functional CL environment, congratulations. You can do everything you’d expect in a REPL, and a lot more you wouldn’t, like intalling libraries.

Lets try something silly:

* (princ "Hello")
Hello
"Hello"
* (quit)

Quicklisp

Currently the best way to explore and experiment with Common Lisp libraries is Quicklisp. Think of it like Python’s pip, but with more parentheses.

Download Quicklisp and follow the install instructions here. Make sure you do the bit that adds Quicklisp to SBCL’s startup script (ql:add-to-init-file) as this makes development way easier… (it makes quicklisp available in any new SBCL instance you create)

Most package managers are invoked from the command line. This is not the case for Quicklisp. Like most things in Common Lisp, you use it from inside the REPL. So, from inside an SBCL REPL, lets install a few useful libraries now by running the ql:quickload function with the package we want to install:

  • Loads of utilities (alexandria) (ql:quickload :alexandria)
  • Regular expressions (cl-ppcre) (ql:quickload :cl-ppcre)
  • Clojure-like arrow macros (cl-arrows) (ql:quickload :cl-arrows)
  • String manipulation (cl-strings) (ql:quickload :cl-strings)

Note: this kind of workflow (working entirely in the REPL) is really nice once you get used to it. The result is less context switching, fewer external tools required, etc.

I’ll probably talk about these libraries in future articles, and will link back here when they’re ready! For details about how libraries “work” in Common Lisp, see Libraries.

IDE

Now that “Common Lisp” is installed, you’ll want something to develop with. If this was a C# tutorial, this is where you’d be told to install Microsoft Visual Studio, or maybe Mono. Really all you need is a programming editor, but what you actually want is a tool that integrates tightly with Common Lisp, greatly enhancing the development experience.

Opinionated stuff here, feel free to ignore it if that bothers you.

Download and install the following:

  • Emacs (version >25)
  • Spacemacs

And then enable the ‘common-lisp’ layer in Spacemacs.

That is all.

(If you have no idea what Spacemacs is, “enabling a layer” probably means nothing to you, in which case you should have a look at the Spacemacs documentation; it’s really good.)

The most productive IDE I know of for developing with Lisp is Emacs. Nothing else I’ve used comes close. For any language in fact. Got something better? Let me know! There are loads of other articles around describing how to setup Emacs for Lisp development, so go and read:

Alternatively, you could use Vim + Slimv. I’ve never done so, and can’t comment.

Even more alternatively, use a full-blown commercial CL implementation and IDE, such as Allegro or LispWorks. If you’re used to using something like Visual Studio, or Eclipse, you’ll probably want this option.

Done!

You now have a Common Lisp implementation installed, a few useful libraries, and an IDE to develop in. YAY.

Was that less than 5 minutes?

Recap

Great, so now you’re totally set up for developing Common Lisp. Lets recap what you actually have installed:

  • SBCL, a popular Common Lisp “implementation”
  • Quicklisp, a library manager
  • Spacemacs, a modern Emacs configuration

SBCL is the thing that “runs” CL code. It contains, among other things, an interpreter, a compiler, and a REPL interface. But SBCL is more than that – the docs are pretty good. Quicklisp lets you easily install libraries. Spacemacs provides a Common Lisp development environment, including SLIME, with enhanced SBCL support – type M-x slime to run it!

Notes on Implementations

I told you to install SBCL. This was not the only option.

“Lisp” is a large set of languages, that, as far as I can tell, includes anything that is written using s-expressions. Opinions vary. Anyway, the important thing is that Common Lisp is a particualar variant, which was standardised by ANSI in 1994. The standard describes the functionality that must be present in a Common Lisp implementation, many (many) of which exist.

There are open source (e.g., SBCL, Clasp) and closed source implementations, and as they all must implement the features specified by ANSI, you are guaranteed some level of portability between implementations. However, the extra stuff bundled with implementations varies, and so you cannot expect any non-standard features to be portable. Notably:

  • Multi-threading ability
  • Unicode support
  • Executable format
  • Execution speed

SBCL is an open source, popular implementation with lots of features that make it great. It has been under development for a long time, and hence is very stable, it has fantastic editor integration (e.g. via SLIME in Emacs), and compiles to well optimised native code. It also runs on lots of platforms.

Other interesting Common Lisps:

  • ECL, which compiles down to C
  • Clasp, for its C/C++ inter-op

Roswell

If you’re getting started with Lisp I absolutely recommend just installing one implementation, as described above, and getting familiar with it. However, at some point you will probably want to use/test a different implementation.

Roswell is an actively developed “Lisp implementation installer/manager, launcher, and much more”, which is becoming more popular for full stack Common Lisp development. Among other things, it lets you install multiple Lisp implementations on one machine, and easily swap between them.

Some people suggest using Roswell from the start, but frankly, it’s just extra complexity that isn’t helpful until you are developing Lisp more seriously.

TL; DR

Skip all that boring stuff, and let me write some Lisp!

You probably want Portacle. https://shinmera.github.io/portacle/