dlweinreb

Take a look at InspireData (http://www.inspiration.com/InspireData). It is entirely written in Common Lisp (http://www.lispworks.com/success-stories/inspiredata.html). The creators of InspireData used Lisp for its high productivity and ease of development.It uses native menus, drop-downs, and so on, and is uses OpenGL. The customers never know it's written in Lisp. There is no problem at all with garbage collection (i.e. no pauses that anyone ever notices).

It's pretty obvious that since you can do this, a game like PacMan can also be done. I don't see any obstacle to writing 3D games. Common Lisp has been used for a huge range of kinds of application.

If you're looking for a languages with no side-effects in the same sense as in Haskell, the Clojure dialect of Lisp is well worth looking at.

Soon, lisp.org will be redone to make it easy to find good free Lisp implementations. Meanwhile, check out my survey paper at http://common-lisp.net/~dlw/LispSurvey.html.

Yes, lisp.org needs to be (and will be) vastly improved. We definitely need the equivalent of a CPAN for Lisp, and several of us are working on producing such a thing. You're quite about marketing!

As for multiple implementations: CPython, Jython, IronPython, Stackless Python, PyPy. What editor do you use? Gnu Emacs with Slime; or, some of the commercial Lisp implementations come with IDE's; and there's work being done ("curl") to make Eclipse work well with Common Lisp. Java has several IDE's, such as IntelliJ and Eclipse. For Python, what I'm told by the Python experts I know is that they just don't use any IDE.

But much of what you're saying above is very much to the point. The comments on my blog posting go into these issues more.

By the way (this is a serious question), what software products have been produced that were written in Haskell?

I disagree about that. It's very, very hard to add Lisp-style macros to something like C or Java. The best attempt to do it for Java is Jonathan Bachrach's Java Syntactic Extender, but as far as I know nobody has built any software with it. It's just too hard to use.

Until you have read a clear description (e.g. Seibel) or had some experience, it's hard to see what macros are really all about.

Lisp macros are extremely important, powerful, and beneficial. Space does not permit me to go into the full explanation; see Peter Siebel's book and the great lecture he gave at Google, available on the web.

Macros allowed us to add object-oriented programming to Common Lisp. CLOS (the Common Lisp Object System) fits in very smoothly into the Common Lisp language, with a nice, clear syntax and very powerful semantics. At work, we have built an object-relational mapping system that, similarly, would be impractical (ugly and verbose to the point of unusability) without macros.

In practice, it's just not a problem, because your interactive development environment takes care of it for you. I think the idea that anyone should be expected to program by using something with the power of Microsoft Notepad is an obsolete view. GNU Emacs with Lisp mode makes it very easy to work with the parentheses.

Meanwhile, we have no "dangling else" problem. Also, we have no need to memorize C's 15 levels of operator precedence, so when you see an expression, you never have to puzzle over how the items are grouped. In simple cases of C expressions, of course, it's easy, but it can get complicated. See "Java Puzzlers" by Josh Bloch and Neal Gafter to see how C/Java-style syntax can get you into trouble and fool you. There are pros and cons to each approach (C/Java and Lisp). I've used all of them extensively, and I prefer the Lisp way.

It's true that earlier Lisp dialects had trouble. But in Common Lisp, you can do currying just fine. At work (ITA Software), it's part of our standard utility library.

I'd like to understand what you mean. Is there a way you could provide an illustrative example?

Thank you for the kind words!

I don't think that Brandon Werner said that Lisp was a failure as a language. As I read it, he's saying that Lisp has failed to capture a lot of new users, get very popular, and so on.

I agree with you that a lot of the really big advantages of Lisp show up better in large systems than in small coding exercises.

There have actually been lots of successful products made with Lisp. People just don't say so, sometimes because Lisp is unpopular and sometimes because it's just not important. InspireData is a great product, but there's no need for anyone to know what language it's in: in fact, it's in the LispWorks implementation of Common Lisp.

For links to success stories, see my survey paper at http://common-lisp.net/~dlw/LispSurvey.html and see the "Success Stories" section.

I recommend that you get in touch with Clozure (www.clozure.com). They know more about contract Lisp work than just about anybody. There are many consultants who work, via Clozure, for companies doing work in Lisp.

Or, apply for a job at www.itasoftware.com. I love working there. See http://dlweinreb.wordpress.com/2007/12/24/16/.

It's true that the system was feature-laden. I think this was more true of the API's than the user interfaces, though, and so I'm not sure that the Steve Jobs reference is exactly appropriate. Steve Jobs is making consumer products; most customers don't care much about the API's.

It was also featureful because we didn't know which features were the ones that would turn out to be most useful; if there had been a second generation, we could have pruned out some of the stuff that never really got used. It was something of a "laboratory" that way.

Also, the kind of people who used Lisp machines, generally early adopter types, really did ask for amazing numbers of features. If you had been there, you would have experienced this. We wanted to make all our users happy by accommodating all their requests. It's probably similar to the reason that Microsoft Word has so many features. Everyone thinks there are too many and has a long list of the ones they'd get rid of; but everyone has a different list! I think Joel Spolsky wrote something very convincing about this topic once but I can't remember where.

Lucid on Suns was eventually as fast, if you turned off a lot of runtime checking and put in a lot of declarations. Later it was even fast if you didn't do that; the computational ecosystem changed a whole lot since the Lisp machine was originally designed. You have to remember how old it was. At the time it came out, it was very novel to even suggest that every AI researcher have his or her very own computer, rather than timesharing! That's early in the history of computers, by today's standards.

No, we didn't teach all of our customers personally, although we did have an education department that taught courses, and some of them learned that way. There were classes in Cambridge and in San Francisco. Allan Wechsler designed the curriculum, and he's one of the best educators I have ever met. (My own younger brother worked as a Symbolics teacher for a while.)

Common Lisp is complicated because (a) it had to be upward-compatible with very, very old stuff from Maclisp, and (b) it was inherently (by the very nature of what made it "Common") a design-by-committee. For example, consider how late in the lifetime of the language that object-oriented programming was introduced. (Sequences and I/O streams should obviously be objects, but it was too late for that. CLOS wasn't even in the original CLtL standard.)

In other words, I'm mainly not disagreeing with your points, just explaining how things got that way.

In all fairness, the manuals that filled a whole shelf documented a lot of major applications. On my desk right now, I have a copy of the O'Reilley book on Subversion (a source control system). I have another book on Emacs. And so on. ALL of those things were covered in that shelf.

Regarding simplicity versus complexity, please see http://www.joelonsoftware.com/items/2006/12/09.html. Different people want different things; you can't just provide the common 20%.

Over the last few days, I have been surveying the WWW for criticisms of Common Lisp. The two that I see most often are: (1) it's too big, and (2) it's missing so many important features like threads, sockets, database connectivity, operating system interoperability, Unicode, and so on. Ironic, no?

It is really too bad that Common Lisp was not defined as a language core, plus libraries. We did originally intend to do that (they would have been called the "White Pages" and "Yellow Pages"), but we were under too much time pressure.

There is no question that Common Lisp is a lot less elegant that it could have been, had it been designed from scratch. Instead, it had two major design constraints: (1) it had to be back-compatible with MacLisp and Zetalisp in order to accommodate the large body of existing software, such as Macsyma, and (2) it had to merge several post-MacLisp dialects, in a diplomatic process (run magnificently by Guy L. Steele Jr) that made everyone reasonably satisfied. It was quite literally a design by committee, and the results were exactly what you'd expect.

But the imperative was to get all the post-MacLisp implementations to conform to a standard. If we failed, DARPA would have picked InterLisp as the reigning Lisp dialect, and we would have all been in a great deal of trouble. (Look where InterLisp is today; actually there's nowhere to look.)

You wonder how other people learned to use Symbolics machines. Some of them took courses - we had an extensive education department. Before you say "that proves that it was too complicated", keep in mind that the system was very large and functional because that's what its primary target market wanted. We did not get feedback from customers saying "make it simpler"; we got feedback saying "add more features, as follows". I bet the people who maintain the Java libraries are rarely asked to remove large amounts of the libraries.

I'm not sure what the reference to Steve Jobs is about. Look at how many features the Macintosh has now. It takes a long time to learn all of them. Their documentation is much shorter because they don't give you any; you have to go to the book store and buy David Pogue's "The Missing Manual" books.

I admit that some (not most) of the complexity was gratuitous and baroque, but not because we liked it that way. The complexity (mainly the non-uniformity) of Common Lisp was beyond our control (e.g. the fact that you can't call methods on an array or a symbol, and so on). Some of the subsystems were too complex (the "namespace system", our distributed network resource naming facility) comes to mind.

In summary, I'm sympathetic to what you're saying, but the reasons for the problems were more involved.

-- Dan Weinreb

Iced tea. (My employer provides it for free...)

Having been a co-founder of two VC-backed startups, I can say that everything in this essay makes a lot of sense, sounds very plausible, and is entirely consistent with my experience. Great essay!