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Kent M. Pitman Answers On Lisp And Much More

timothy posted more than 12 years ago | from the 64kb-is-the-limit dept.

Programming 346

A few weeks ago, you asked Kent M. Pitman about Lisp, Scheme, standards, and other things -- He's answered your questions below, at length. At such length, in fact, that only the first eleven of his answers are shown below -- expect more shortly! Thanks, Kent.

1) (just one thing (I) want to (know))?
by An Anonymous Coward

((
What (
(is) with (all)
) of (the) ()s?
)
Hmmm?
)

Kent M. Pitman: This question actually got scored down to -1 and marked as a troll question, but I fished it out of the barrel and restored it because everyone asks and I might as well confront the issue head-on.

Ironically it's non-Lisp languages that allow and encourage you to put ()'s in any place you want, as if there were no meaning to the introduction of gratuitous paren groups.

3+(2*5)+7 means the same thing in an algebraic language as does 3+2*5+7. In Lisp, we write:

(+ 3 (* 2 5) 7)

This shows you the structure and means you never have to learn obscure precedence rules that make expressions like -3! confusing in algebraic languages, where you must learn whether it means (-3)! or -(3!). In Lisp, the parens would show you immediately that (factorial -3) or (- (factorial 3)) was intended.

The thing I personally like about (+ (* 2 y) x) rather than 2*y+x is that it simplifies my editing. I'm a touch-typist and I use the emacs commands to go forward and backward over expressions, to swap expressions, and to delete expressions very heavily. And I don't have to reach for the mouse to manipulate large, complex expressions because they are paren-bounded. If I put the cursor at the head of 2*y+x and say "go forward an expression", ought this go forward over 2, 2*y, or 2*y+x? Having different editor commands to move across a sum, a product, etc. would be unwieldy. Yet without that, I don't see how the editor would know. In Lisp, there can't be any ambiguity because every sub-expression has its own start character, so a single notion of "the expression in front of the cursor" or "the expression after the cursor" suffices.

This, by the way, also answers the question of why we don't write foo(x) and instead write (foo x). In Lisp notation, foo is an expression. In the expression (foo x), it's a subexpression, so it's enclosed within it. Were it outside, a text editor would not be sure if foo(x) were one expression (a function call) or two expressions (the symbol foo followed by the list (x)). That would make going forward over 'one expression' ambiguous when at the start of foo(x). Should the cursor end up after the foo or after the (x)? In other words, The natural purpose of parentheses is to enclose things, so that's what Lisp uses them for. Avoiding ambiguity is critical to the writing of correct "keyboard macros" in Emacs, where I might interactively write a program to do a lot of code transformations quickly. In an algebraic language, such keyboard macros can be much harder to write robustly.

2) It's not just me is it?
by demo9orgon

After trying to "self-learn" lisp in the 80's I get this physical reaction to the word "lambda"...a cold sweat combined with the involuntary retraction of my testicles to a protected location in my abdomen (damn unpleasant shit)...I usually avoid that second one by mentally going through the mechanics of "hello world" in C, or any half-a-dozen other programming languages.

Lisp is one of those meta-languages you either learn or avoid. I write practical stuff all the time, daily in fact, and I've never had something that required the arcane stuff in LISP.

KMP: Actually, "hello world" in Lisp looks like this:

(defun hello-world ()
(write-line "Hello, World!"))

I don't know about you, but I find that pretty soothing.

And as to LAMBDA, one only needs use it when they find it useful. For example, after a while, one sometimes gets tired of writing a separate function where that function will only be used once, as in:

(defun sort-by-name (list)
(sort list #'name<))

(defun name<(name1 name2)
(or(string<(last-name name1) (last-name name2))
&nbsp(and (string= (last-name name1) (last-name name2))
(string< (first-name name1) (first-name name2)))))

so Lisp allows one to instead say:

(defun sort-by-name (list)
(sort list #'(lambda (name1 name2)
(or (string< (last-name name1) (last-name name2))
(and (string= (last-name name1) (last-name name2))
(string< (first-name name1) (first-name name2)))))))

Whether one actually does this is purely a personal preference. Some people like having separate named functions, some don't. Sometimes the separately named function might have a nonsensical name, though, and it's nicer not to have to invent a stupid name for a one-shot use.

Now, as to why it's called LAMBDA and not FUNCTION, that's just a piece of history. You get used to it. Toward that end, I'll offer a story that will perhaps help you put it in perspective:

Early in my not-yet career as a computer scientist, which is to say, while I was in high school, I lived in the Panama Canal Zone. Computers were not at all common there at the time. In fact, the place being entirely run by the US Government, there was some weird edict that said no one was allowed to own one so that they would all be centralized in the Comptroller's Office and not wasted in individual offices around the Zone. Our school had to bend the rules in order to get us a computer to study. So one thing I did while trying to learn about computers was to go downtown (out of the Canal Zone into Panama City, in the Republic of Panama) and visit a company there who did computer work. Of course, people there spoke Spanish, but fortunately I did, too. They showed me some of their code, and I was immediately struck by the fact that all the language keywords were in English.

"Doesn't that bother you?" I asked. But the person I was talking to was quite a thoughtful person and he immediately responded this way: "Do you know how to read music?" "A little," I said. "Have you seen the notations on music like forte, sotto voce, and so on?" I nodded. "Does it bother you that they are in Italian?" "No," I had to admit. His point was to make me see that it could be viewed as part of the charm and history of the notation. He was, perhaps, unusually forgiving. But this was in the late 1970s, when everyone who had access to computers was far too excited about just plain having them to care about subtle issues of whose culture got too much say in the design of a world-wide phenomenon.

So when today I look at the very few mysterious-looking terms like LAMBDA, CAR, and CDR that still linger untouched in modern Lisp's design, I think of them as I do those musical notations, conceptual links to a little piece of history that I'm just as happy not to see crushed by an overeager rush to regularize and homogenize the world--something the computer culture has done altogether too much of.


3) Interactively programmable applications
by divbyzero (divbyzero@hotmail.com)

One of the primary reasons why Scheme and Lisp interest me is that they are well suited for making applications interactively programmable at runtime (Scheme especially, due to its small size). This is far more flexible and useful than applications which are only extensible through heavyweight, precompiled plugins. Since the Slashdot readership tends to be made up of people who are comfortable with programatic interfaces (unlike the general computer-using public), why do we not see more such applications?

KMP: I think it's just an issue of education, formal and otherwise. Without being explicitly guided, some people will try out all kinds of ways to do things, or invent them where they're not present. But many others will simply do what they have been taught to do without exploring the alternatives.

In the past, everything was about speed. Every instruction was precious. The focus was entirely on "micro" efficiency. People would examine the cost of being able to redefine something (which sometimes involves as much as following pointer indirection), and if there was a cycle lost, the game was over. Today, hardware cache and prefetch architectures can often hide such costs anyway, but even if they couldn't, processors run so fast that one has time to worry not only about micro efficiency but also macro efficiency--that is, "running smart", not just "running fast", as a way of assuring total efficiency.

A lot of people identify Lisp as a language that is "just good for Artificial Intelligence (AI)". Certainly Lisp is good for AI. But saying it is just good for AI misses the point. Lisp doesn't do AI. Lisp is a programming language. AI researchers program AI, and often their language of choice has been and continues to be Lisp. But the important thing is that AI researchers have been banging on the door of Lisp implementors for years, demanding the introduction and tuning of the features and constructs they need in order to get their work done. Lisp hasn't become a mere AI toolbox as a result of that. Rather, it has become a robust tool for addressing the world's most complex and vexing problems. The Lisp community has a long experience with supporting "intelligent programming", and with doing so efficiently.

Lisp's biggest problem in the past is probably that it hit its commercial peak too early, in the mid 1980s, before most computational problems the world was confronting were big enough to need the power Lisp had to offer. Those were the days of MacWrite and MacPaint and Lotus 1-2-3, and it just didn't make any difference whether one used Lisp or C for those. But for better or worse, the world has grown up around us, and the important problems of the day are a lot more complex. I think Lisp has a lot more to offer to the world of today than it ever did in the past.

4) The standard process
by VP

As participant in the standardization process for Lisp, what are your thoughts on standards for programming languages? What would you like to see different in this process? And speaking of standards, what do you think about the RAND licensing issue and the W3C?

KMP: I think standards have served their time to provide a stable base for people to build on, but for the modern environment, they move way too slowly to keep pace with the speed of change in business. It took a long time to put the Common Lisp standard together. We began in 1986, finished work in 1994, and got the actual document to press just before the end of 1995. Getting community consensus on something that big really does take that long, and I think it was an exercise worth doing to create the stable base that we created, but for future evolution of the language, I think there needs to be another way with far less overhead.

I see standards as having two components: The first is to simply cast a name into concrete so that reference to that name will always have a clear meaning. The definition of ANSI Common Lisp, at least for 1994, is now permanently registered. Anyone who wants to can now conform to that definition and others will know exactly what they mean by that. The second component is to assert an informal consensus in the community that there is a single right way of doing things. This latter component may be useful for the foundation (to define the initial market space), but I'm not sure it's appropriate for the library level of the language.

For the base language, if 60% of the community wanted to do things one way and 40% another way, the 60% got to roll over the 40%, and 100% of the community was expected to do things in the way that won. But at the library level, if 60% want one library and 40% want another, I'd rather 100% of the community get what they want by having some people just do it one way and the rest of the people do it the other way. The Lisp community has not traditionally done things that way; they've sought consensus. The Scheme community has been even more conservative about this than the Common Lisp community, and as a result has even fewer standardized facilities than the Common Lisp community.

The Scheme community has moved to a more loose-knit approach to break the design deadlock brought on by the core language committee's consensus process through its Scheme Requests for Implementation (SRFI) process. The Common Lisp community hasn't got anything quite so organized yet, but I suspect will eventually evolve something similar.


As to the question of the W3C, I'm not a huge fan at the moment. At a prior employer, we had the opportunity to join, but the contract we'd have had to sign made it clear that votes among members were advisory only, and W3C itself could decide to override what people voted on. This, to me, is not a consensus body. Furthermore, although I think standards bodies like ANSI move in near glacial time, I don't think you can fix things by just shortening the times. True national and global consensus just takes time, and shortening timelines doesn't just make things move faster, it also disenfranchises people. While I use the existing HTML, CSS, XML, XSL, and other W3C guidelines, I don't feel they were created in a manner that I respect as proper consensus process. I think the process was insular and rushed.


Neither am I happy with the notion of processes involving Reasonable and Non-Discriminatory (RAND) fees being part of a standard; I think consensus standards should only involve royalty-free (RF) technologies. I think adherence to standards should not induce a baseline cost beyond the cost of creating the code so that the cost of compliance with standards can closely approach zero. If there is a profit to be made on the implementation of a standard, it should go to the implementor, not to a patent holder. Then again, while I'm a strong proponent of software copyright, I'm not at all a fan of software patents. Rather than seeing independent creation as infringement, I think independent creation should be contributory proof that an idea was more obvious than perhaps the patent office thought. I don't mind copyright because there are ways that one can demonstrate that one did not merely copy another's work, and independent creation is a defense.

5) Advice to Aspirants
by An Anonymous Coward

Kent, I am one of the lucky ones who programs professionally in Common Lisp. I certainly appreciate your hard work and the hard work of everyone else who helped to bring us the ANSI standard - which serves to reify much of the esoteric knowledge the Lisp community has developed in the many years since the language was born.

While I do not need to be sold on Lisp, I know many people who do not fully appreciate the power of the language. To a large degree, this is due to misconceptions about the language. Specifically, there seem to be a number of what I would call 'cultural misconceptions'. Because many people have never worked in a tightly interactive development environment with incremental compilation, language-level introspection, and real code/data equivalence (not to mention the differences between CLOS and what the rest of the world seems to have come to believe is the God-given definition of 'object-oriented' programming) - they don't really 'get' what makes Lisp so special and so powerful. More to the point, because the logistics of developing and deploying applications in Lisp is different than what the typical c/c++/perl/java developer knows, the hurdle to even investigating or considering Lisp as a real possibility seems unnecessarily high.

Could you talk a bit about how those who have a feeling that Lisp might help them with their hard problems could go about bootstrapping their way into finding out? How would you suggest getting started? What is a reasonable set of tools for experimentation, and where should a beginner start with the language? (The standard is a big document!) Also, could you give an example of the type of problem space and style of application delivery that demonstrates that Lisp is more practical than many seem to believe?

KMP: Well, one thing to note is that there's very little overhead to just downloading an implementation and diving in. Not only do the major commercial vendors like Xanalys and Franz offer high quality, no-cost trial versions of their proprietary software, but there are quite a number of free (non-proprietary) versions of Lisp as well. Information about these, as well as much other useful information about Lisp, can be found at the Association of Lisp Users (ALU) web site. I've also recently purchased common-lisp.info, which I plan to maintain as a repository for information about Common Lisp; the site doesn't have a large base of information yet, but it does have a list of the problem spaces in which you might consider using Lisp.

The ANSI Common Lisp standard, effectively available in webbed form as the Common Lisp HyperSpec, is indeed a big document (about 16MB and having about 108 kilohyperlinks downloadable). I think it's fairly readable as standards go. But you're right that it takes some work to get through and it wasn't really intended as a tutorial.

The ALU web site will also have pointers to books and online tutorials about Lisp. Books by Paul Graham and Peter Norvig on the subject are very highly regarded. I think there is always room for more, and I'm working on several, at least one of which I hope to complete in the not too distant future; feedback from you and others is useful to me in understanding what areas most urgently require treatment.

One resource that some people might find useful is an article I wrote called Accelerating Hindsight: Lisp as a Vehicle for Rapid Prototyping. This article is intended primarily for a Lisp programmer audience, to help them articulate some of the ideas you've asked about to others. It was not intended to be read by the audience you'd like to convince mainly because it appeals periodically to Lispy notation that might not be familiar to them, but it may still be of interest to the adventurous non-Lisp reader.

As your project becomes more sophisticated, and evolves from a personal toy to a real commercial product, it also doesn't hurt to ask an expert for help. My company offers consulting services that include helping companies manage the transition into Lisp. One of my major clients, The Software Smith approached me on just such a basis and the result has been very exciting both for me (getting to help them improve their system) and, I think, for them (getting to see more of how Lisp is supposed to be used). I don't want to turn this interview into a huge advertisement, but people can contact me for more information. If I'm either not competent to help you or am too busy to help you, there's a very good chance I can refer you to someone else who can help you.

6) Language feature trickle-down
by WillWare

I was a big Scheme/Lisp fan five or six years ago, but now I see most of my favorite Lisp-like language features available in Python, which is getting a huge amount of high-quality development mindshare these days. Some of the Lisp-ish features in Python that spring right to mind are functions as objects, closures, garbage collection, and dynamic-yet-strong typing, and convenient rapid-app development.

One needn't look far to find arguments that there is still something unique to Lisp that differentiates it even from very recent languages which have had ample opportunity to borrow from Lisp. But one rarely finds a really clear articulation of that uniqueness. Do you think concur with the view that Lisp is still unique, and if so, do you think that Lisp's putative advantage really is ineffable?

If there is an advantage but it's ineffable and therefore opaque to managers with purchasing power, that would explain why Franz, Harlequin, et al have had such a rocky road. Does the Lisp/Scheme community regard this as a worrisome issue? (Some folks on c.l.lisp clearly don't think so, but I don't know if they are just a noisy minority.)

KMP: I guess I think Lisp is unique, but whether it is or not doesn't affect its usefulness as a tool. I'll enumerate some things I like about Lisp, but Slashdot readers shouldn't assume that I'm asserting for each of these features that Lisp has a lock on these. Various other languages surely have some of these. But I am often heard to say: languages are ecologies. Language features are not a priori good or bad. Rather, language features are good or bad in context, based on how well they interact with other language features. Some of what makes Lisp what it is has to do with the features it offers, but some of what makes Lisp what it is has to do with how the features work together to make a coherent whole. Lifting some of these features out of context might sometimes work, but in other cases, it might not. To get a real feel for Lisp, or any language, I think you have to really use it.

Also, in my 1994 article Lambda, the Ultimate Political Party, I advance the hypothesis that languages are defined as much by their community as by their semantics. That is, languages are forever in flux, and the semantics you read about in a language spec is a point in a multi-dimensional space telling you the current location, but it does not tell you the velocity vector in that space. For that, you must look to the community. Even if two languages happened to occupy precisely the same point in design space, that is, if they had the same semantics, would they continue to over time? I think not.

For what it's worth, here are just some of the things I personally like about ANSI Common Lisp:

  • Lisp is dynamic. The world is ever changing and it's useful to allow programs to change dynamically with it. I can load new or changed functions, classes, and method definitions into a running image that I'm debugging, or even in a deployed production application. When I do, the code that was running will immediately start using the new definitions. Classes can be redefined even if the new class has different slots, and, if I care to, I can control how the update is done from old to new slot arrangements for already-created instances. This kind of thing supports programs that must be continually running yet must be responsive to changes or even just bug fixes.

  • Lisp is introspective. Not only can functions, packages, classes, methods be dynamically added, redefined, or removed, but programs can also inquire about whether aspects of the programming environment (functions, packages, classes, and so on) are defined, can manipulate those objects as data, can save them away, can transform or encapsulate them, etc. Also, the Lisp compiler is a standard part of the language and can be invoked even at runtime by applications that need to augment themselves. New programs can be created on the fly, then compiled and loaded and executed in the same running image as they were created, without ever exiting (and even without doing file I/O). This facilitates automatic programming and the development of layered languages.

  • Lisp's syntax is malleable. There's nothing worse than being stuck in a syntax that you don't like in a language you're going to use for a long time. Lisp allows programmers to reconfigure the syntax rules for parsing characters into data and programs, as well as allowing macro technology that transforms one parsed program expression into another. And it allows control of how data is displayed during program execution and debugging. Moreover, this can generally be done in such a way that one programmer's customizations don't adversely impact another's. This makes interactions with Lisp more pleasant and debugging sessions more productive.

  • Lisp doesn't force users to use variable type declarations in order to just get a program to run. The initial focus in Lisp is on getting programs working. You can add type declarations when you're done if you want to, in order to enable additional compiler optimizations. This facilitates rapid prototyping by first getting an application running quickly with low overhead, and then allowing an application to be tuned as a second pass operation.

  • Lisp has a powerful class system, and a flexible meta-class system. The class system allows powerful slot and method definition, method combination, and a great many other detailed features. The meta-class system allows users to treat the object system as data that can be programmed, creating new kinds of classes.

  • Lisp gives the user powerful tools for both signaling and handling errors. This means that when an error occurs, there are often a variety of ways to continue programs other than simply aborting or dumping core. Moreover, object-oriented error handling allows programs to represent errant situations, evaluate the options for how to proceed, and select an appropriate option under program control.

  • Lisp uses automatic memory management. This means that when a programmer is done with an object, they just let go of it and the garbage collector reliably frees its storage. This means Lisp programs do not suffer from the memory leaks that commonly plague programmers in many other languages.

7) What will it take to make Lisp fashionable again?
by kfogel

For myself and a number of friends, Lisp/Scheme programming has for too long been a kind of mystical Eden, fading in our memories, from which we have been mostly banished in our professional lives. But we can still recall how it felt to work in a language able to shape itself to any pattern our minds might ask: coding was more interesting and more expressive, and the rate of increasing returns over time was tremendous, because fine-grained -- almost continuous -- abstraction was in the nature of the language. Life was just more fun, frankly.

Alas! In our jobs and even in our personal projects, we are often forced to use C, C++, Java, Perl, or Python -- not because we prefer to write in those languages, but for two much less satisfying reasons: first, everyone else knows those languages, so we'll get more developers with them. And second, you can't count on users and testers having the right environment to run programs written in Lisp/Scheme, so right away you take a portability hit if you choose to develop in them.

Do you think there is a chance of Lisp/Scheme becoming "mainstream" again? That is, when someone contemplates starting a project, it would be as realistic for them to consider Lisp or Scheme as, say, Perl, without worrying about losing developers or initial testers? What will it take?

KMP: First, let me say that I really appreciate the poetic description you offer in the first paragraph above. I very much think that captures how I and others think about the experience of using Lisp.

And as to the future of Lisp, I think the situation for Lisp is looking pretty upbeat these days. Enough so that my own infant business is building its tools in Lisp, both for sale and for our own internal use on products we produce.

There are a lot of implementations, both commercially maintained and "free", with a wide range of delivery options, from conventional executables to "remote" solutions: Some implementations support CORBA and/or COM interfaces, for example. Also, most implement some kind of sockets interface, and there are several Lisp-based web servers available that build on this. Lisp programs can dynamically load DLLs, or can be delivered as DLLs themselves. They can do "foreign function call" to functions in other languages. It can also communicate with databases, and so with other programs via databases.

As the world moves increasingly to high-bandwidth global connectivity, I think the issue of the delivery environment will become less important. People have been waiting for an e-Service based society to take off, and it hasn't quite done that yet, but I think it's coming. I can't see how it won't. The overall savings in quality assurance and support of not having to re-deploy an application in a hostile customer-premise environment will be a lot, just as your question implies. One will just bring an application up on the right kind of hardware, connect it to the net, and then forget about where the program is actually being used. That may be an oversimplification today, but I wouldn't waste my money betting against it for tomorrow.

8) Questions I've Come Across Learning Lisp
by Jon Howard

I was recently (April) hired-on as webmaster at Franz [franz.com], a commercial lisp company (we make Allegro Common Lisp [franz.com]) which has introduced me to lisp in a very loud way. Since joining these guys (and gals), I've been thoroughly indoctrinated - with my full consent - because of my belief that as computing hardware progresses programming in more abstract languages will allow for more creative and effective use of the platform. Sure, coding assembler on a new super-duper petaflop chip will still be possible and less wasteful, but who would want to code a million lines of asm to save a few (or even a few thousand) operations out of a few billion, or trillion when it will only net a difference of nanoseconds in the end? I'm less interested in making super-fast programs than I am in making artistic and super-functional programs.

I'm not expressing the views of Franz, every member of the company has their own beliefs on what makes for great programming - which is one of the major reasons I find this place so fulfilling, everyone has complex reasons for their design considerations, and everyone communicates them (something I've grown to appreciate from working in too many places where this was definitely not the case), and consequently I've been exposed to quite a few different techniques of Lisp coding since my introduction half a year ago. I'm constantly amazed that so many different styles of programming can be expressed in the same language, it's capable of accommodating any logical thought process that can be converted to code - and I doubt many of you often use recursion in a logical way on a daily basis, but even that can be done efficiently in lisp.

I'm still very new to lisp, and I was never a serious programmer in the past, but I've always been accustomed to asking questions, and here are a few that I'd like some input on:

  • If you learned any other programming language, did you initially find the formalities of its structure to be a significant stumbling block to understanding the language as a whole? Was the same true of learning lisp?
  • How much time do you spend debugging non-lisp code? How much on lisp?
  • What language took you the most time to learn - was it your first?
  • What feature do you consider to be the most important for an abstract language to support efficiently - and which features have you found to be most poorly implemented in lisp distributions?

I'd love to hear about what people think sucks about lisp and needs improvement - or can't be improved, so far I haven't found anything that I could complain about, the most difficult thing for me has been managing all the documentation on a half-century old language in the process of learning it. I've begun to love working in lisp, but I suppose being surrounded by a group so full of passion for it has helped contribute to my bias - if I'm wrong, help snap me out of it with a good argument against using lisp. ;)

KMP: I knew FORTRAN and Basic before I learned Lisp. And I've dealt with numerous languages of all kinds since learning Lisp. With most, the syntax itself is generally not a burden. Some languages have more pleasant syntaxes than others, but the human brain has an amazing ability to cope. Of all the many languages and syntaxes I've seen, about the only thing I've never been able to cope with is the "*" used to notate indirection in C. I understand thoroughly the notion of pointer indirection, and the difference between "pointer to array" and "array of pointers", but I find it forever hard to read and write that particular awful notation for some reason. Give me Teco or Perl any day.

Mostly, though, I think the issue of how hard a syntax makes it to learn a language is overblown. Humans have brains that are adapted to processing myriad special cases and can mostly cope with obscure syntaxes. The real issue is how hard it is for humans to pass on their knowledge to programs. People are good at judgment, and programs are good at repetition. Over time, though, judgment tasks become repetitive and it's time for programs to take them over. I like to write macros to package up things I do a lot, and the key to that is having a reliable mapping between program syntax and program structure. The last thing one wants is a macro language based on character syntax, since such syntax is too unpredictable. Lisp offers macros based on program structure, and that greatly reduces the number of programmer errors one makes in macro writing.

As to debugging, I try to use non-lisp code as little as possible because of how hard it is to debug. Most other languages don't have good visual representations of their data, so when I get in the debugger, the manner in which I am presented with errant data is usually low-level and hard to read. A great deal of my valuable time is spent painstakingly piecing structure back together. But in Lisp data objects have familiar visual representations and I find it's usually easier to see what has gone wrong.

What language took me the most time to learn? Probably Teco. There was a lot of trivia to learn there. What language took the least time? Probably FORTRAN, BASIC, Lisp, HyperTalk, and MOO. Fortran just because it was small. The others because they are highly interactive, which is a huge boon to learning.

Actually, I learned PostScript very fast, too. There are some excellent cookbooks on this. But I never learned to debug PostScript. When my programs erred, I mostly just wrote them anew and hoped they'd work then because debugging was too painful.

What do I consider it most important for an abstract language to support efficiently? My time. Time is the only true, non-renewable commodity. I eschew languages like C because they often waste enormous amounts of my time trying to develop and debug programs, and justify it on the basis of micro-differences in speed that have just never ended up mattering to me. I regard C as appropriate for use as an assembly language, but it doesn't provide enough high-level services for me. When I'm old and grey and look back on my life, I want to have done a lot of interesting things, not just have done a few interesting things but "boy were they fast".

I think it's important to pick a language not on the basis of how fast its implementations are today, but on the basis of how much they do what you want. Lisp has an undeserved reputation for being slow, which I think results from deciding to make it do things that there are not always known optimizations for at the outset. Like garbage collection. But as Lisp is used, people complain about the things that are slow, and fixes get found. So Lisp moves ahead. If Lisp had started instead only with the things it knew how to implement efficiently, it would be holding things back. I want my ideas to lead my technology and my tools, not to have my technology and tools leading my ideas.

9) Basis set for programming languages?
by PseudonymousCoward

As a Scheme and Common Lisp programmer, I got excited when I heard that the Java Virtual Machine would have automatic memory allocation and garbage collection. I thought it would be possible to build Lispish languages to run on the JVM. The rate at which Kawa has been developed, to implement a near-Scheme on the JVM has been frustrating to me. I attribute this at least in part to the absence in the JVM of a construct equivalent to Scheme's continuations. Do you think it is feasible to establish a "basis set" of programming language concepts on which all programming languages could be built, so that the distinctions between C, Scheme, etc would be "merely" syntactic? If yes, please enumerate your candidate set.

KMP: Well, continuations are just functions. What's really lacking to make this easier is good tail call support so that continuations can be called correctly without pushing stack.

I don't really have personal experience with using the JVM directly, but my experience with the MOO programming language led me to believe that there might be a problem with integrating tail calling and security, since sometimes security is implemented by asking "who called me?" and tail calls can mean that the apparent caller is not the real caller. So I asked my spies at Sun about this.

I'm told that the original security model for Java worked the way I expected (by examining the call chain), and that concern over consequent security matters contributed to the absence of tail calling support in early releases. But apparently it was conceded a long time ago that such support should be added some day, and that day simply hasn't come yet. So perhaps there is hope.

Even so, I'm not so sure no matter how hard you try that you can just paper over the many differences between languages and say that the only remaining issues are ones of syntax. I do think you can probably get to a point where all languages can compile to this machine, but that may not always mean that programs in one language are as efficient as those in another, or that data structures in one language are as naturally represented as those in another. For example, both Lisp and Scheme assume that small integers (that would fit in a machine number) are still integers; they don't have the int/Integer disjointness that Java has. A Lisp-to-JVM compiler could presumably hide this distinction, but it would be wrong to say that the only difference between Java and Lisp was syntax--there are really some material philosophical disagreements between the two languages.

10) Scheme as an XML Translation Language
by Evangelion

I've become fairly interested lately in using Scheme (probably mzscheme) and the SXML package as a way to do arbitrary XML translations in my free time (if I had any).

From the looks of it, the ability to create a reflexive mapping between an arbitrary XML document and an interpretable programming language is too powerful to be ignored.

Do you think that in the future one of the primary roles of Scheme/Lisp is going to be in manipulation of XML documents, or is this going to be relegated as an academic curiosity while the world struggles through parsing XML in Java?

KMP: Are those my only two choices? The second one sounds awfully bleak. I'd better choose the former.

I don't know whether you'll see XML as a formal part of either Lisp or Scheme any time in the near future, but a lot of that is because the standards bodies administering these are not extraordinarily active at this time. That doesn't mean the languages are dead, just stable. Ongoing work is mostly happening at the level of libraries, and such libraries can generally be written by anyone using existing primitives, without modifications to the core language.

Lisp manipulation of XML and HTML is something people have been working on for a long time. For example, the Document Style Semantics and Specification Language (DSSSL) was a purely functional, side-effect free variant of Scheme. Even XSL, the apparent replacement to DSSSL, offers the same kind of functionality. It just uses a more CSS-like page model and XML syntax. But, conceptually, it's Scheme inside.

In my recent professional life, I have personally written several XML parsers, all in Lisp, for various employers and most recently for myself and my fledgling company. My company's implementation is not available on the market yet, but when it is, I'm quite sure the chief competition will not be around the availability of mere "availability". Already there are a variety of libraries related to XML, XSL, and SAX floating around. And I'm quite sure there will be more to come. Competition will be over things like efficiency, robustness, representation, and optional additional features.

11) Lisp vs. the world
by hjs

What do you see as the unique strengths and weaknesses of Lisp?

What strengths does it specifically have over other functional languages (such as ML), over structured languages (such as C, Algol, etc), over object oriented languages (such as C++, smalltalk, simula, etc), and over scripting languages (such as TCL, perl, etc)? Can these other languages or classes of languages be enhanced to include these strengths? If so, how, and if not, why?

What about weaknesses? What do you see as the weaknesses of Lisp, both in general and in comparison to the above classes of languages? Can these weaknesses be eliminated? If so, how and if not, why?

I mean strengths and weaknesses not only in the formal sense of the language itself, but also in terms of its usability in today's world. For example, difficulty in delivering binaries or lack of accessibility of system libraries from within common implementations of a language would be considered weaknesses.

KMP: There are so many things I like about Lisp, but most of them come under the heading of "doing things in the right order."

For example, type declarations in many languages are required but in Lisp they're optional. I prefer to first get my program working, and only then to tune it to be more efficient by adding type declarations. What's the point of doing a lot of make-work declarations if you're not even sure you're going to keep the result? I do a lot of exploratory programming just to answer "what if" questions. I also write lots of little throwaway programs just to compute a simple result. I don't need such programs to run in 5 microseconds instead of 10.

I also view the process of programming as a series of "times" at which decisions can be made: "coding time," "parsing time" (Lisp calls this "read time"), "macro expansion time," "compilation time," "load time," and "execution time." Lisp gives me a great deal more control for each piece of code as to when it runs, so that it can run at the appropriate time when the data it depends on is known. Other languages, especially statically typed ones, often make me specify information too soon, before it is really known, which usually means "making up" answers instead of really knowing the answers. Sometimes that makes programs run faster. Sometimes it just makes them run wrong.

And I like Lisp's willingness to represent itself. People often explain this as its ability to represent itself, but I think that's wrong. Most languages are capable of representing themselves, but they simply don't have the will to. Lisp programs are represented by lists and programmers are aware of that. It wouldn't matter if it had been arrays. It does matter that it's program structure that is represented, and not character syntax, but beyond that the choice is pretty arbitrary. It's not important that the representation be the Right® choice. It's just important that it be a common, agreed-upon choice so that there can be a rich community of program-manipulating programs that "do trade" in this common representation.

I write a lot of macros because there are a lot of interesting things one can do with macros in Lisp. In other languages, macro-writing is a process of manipulating strings containing input syntax. That feels very unreliable and I've never liked that. Lisp's willingness to represent its code in known data structures makes macro writing feel a lot more reliable. And the presence of macros in Lisp generally means that the boring parts of coding get removed, because repetitive patterns usually get captured by a macro and hidden away, keeping the developer's attention on the "interesting parts", and making the activity of programming itself both more fun and more efficient.

Could other languages borrow some of Lisp's strengths? Sure. And they do. Java, Dylan, and I suspect even C++ have all borrowed ideas from Lisp. But that's ok. We'll make more. And anyway, it's not a zero sum game. Everyone benefits when there's this kind of cross-pollination, whether it's Lisp influencing other languages or vice versa.

Weaknesses of the language? Well, that's harder to say. I think the basic design is quite strong. Sometimes you see an implementation that has put more energy into some parts of the language than others, but usually that has created a market opportunity for another, so overall we have our bases covered.

For example, you might find some implementations that have big "hello world" footprint sizes compared to "hello world" in other languages. Some in the Lisp community, don't think this matters much, because disk and RAM are getting ever cheaper. "Real" applications (i.e., not "hello world," but something meaty) of 5-10 megabytes are pretty commonplace these days. Years ago, Lisp used to be seen as large, but due to such criticism, Lisp has held its size constant in the last decade while other languages and systems have bloated rapidly. So nowadays, Lisp is comparatively quite small. And even still, if you don't like the size you get from one vendor, it seems there's always another trying to squeeze into the niche of addressing your need. Corman Common Lisp (an up-and-coming commercial implementation) and CLISP (a GPL-style "free" implementation) have given special attention to this issue. So there's a vendor for everyone on the size issue. And, though I deal more often in Common Lisp in my day-to-day work these days, I would be remiss if I didn't mention that image size is also a key concern of the Scheme language community, so that's yet another way the size issue is addressed for those who see it as critical.

Some might have heard that Lisp, being dynamic, doesn't make use of static type information. This isn't quite right. In fact, the language doesn't require static type analysis, it merely permits it. This gives a lot of leeway to each implementation to address the specific needs of its own customer base. The CMU Common Lisp implementation has, for example, addressed the issue of type analysis in great detail and offered a clear demonstration that there are many exciting things that implementations of Common Lisp can do with type declarations if they choose to.

Why don't all implementations optimize all of these aspects--footprint size, static type analysis, etc.? The Common Lisp language is admittedly conceptually large and correct, efficient compilation requires considerable time and cleverness to implement. "Why not make the language smaller so it requires less work to implement?" is a query you hear a lot from the outside, and even from members of the Scheme community. The answer from the Common Lisp community amounts to this: Programs are written all the time, but implementations are written much more rarely. What the implementation does not do is left for the user. The more hard work the language does, the less hard work programs do. In effect, the thesis of Common Lisp is that bigger languages make for smaller sentences in the language. (To see that there is at least some intuitive basis for this, think about how long a novel like Gone With the Wind is in English, then try to imagine whether the same novel re-expressed in Esperanto would be longer or shorter.)

If a language offers only what a programmer could implement overnight, it gives its programmers not much of a leg up on their final application. Many members of the Scheme community boast that they have written a Scheme implementation, while many Common Lisp programmers have not. Common Lisp is surely harder to implement, but the Common Lisp community does not see as its primary purpose to put out legions of implementors, each with their own easily-created implementation. The Common Lisp community has chosen to be about commercial applications, and its designers have provided a "meaty chunk" of useful power for programmers to use, with the promise that if programmers write their programs to that standard, not only will those programs work well today, but as implementations get better, those same programs will work even better tomorrow.

[to be continued...]

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346 comments

LISP IS GAY (-1, Flamebait)

Anonymous Coward | more than 12 years ago | (#2538240)

FP!

I cant wait ... (-1)

benevolent_spork (446160) | more than 12 years ago | (#2538299)

For the first "didnt you read the article" comment. I wish we could set the maximum chars for stories field as it truly s0x0rs to have to scroll so fucking far down to get to the juicy troll tidbits.

YeeeeFuckingHaaaaw! (c) Spork_Testicle, 2001

that would be unfair to Katz (-1, Offtopic)

Anonymous Coward | more than 12 years ago | (#2538377)

he wouldn't even get out of his first angsty pro-geek introductory paragraph

TROLLS OWN SLASHDOT (-1, Offtopic)

The_Messenger (110966) | more than 12 years ago | (#2538242)

We shall continue to terrorize the Posters and cost you ad revenue unless the following demands are met:
  1. NP, N&P
  2. One bowl of hot grits
  3. Forty acres
  4. A mule
  5. Adultcheck passwords
  6. Windows XP site licenses
  7. JonKatz's head, on a stick, covered with caramel
That is all. Thank you.

99 Morally Bankrupt Sand Bunnies On the Wall ... (-1)

benevolent_spork (446160) | more than 12 years ago | (#2538243)


99 Towel Heads Up On The Wall ...
99 Sheep fucking twits,
You shoot one down,
You kick it around,
98 Rag Heads left on the Wall.

98 Cumlicking Chickenshits on the Wall,
98 Camel sucking penis stuffers,
You shoot one down,
You kick it around,
97 slimy turds left on the wall.

97 Raghead Swine on the wall,
97 Shit Encrusted pukes,
You shoot one down,
You kick it around,
96 flea harbors left on the wall.

96 Moronic idol polishers on the wall,
96 pink skirted sphincter tasters,
You shoot one down,
You kick it around,
95 pillow biters left on the wall.

95 pustuled penis suckers on the wall,
95 festering maggots,
You shoot one down,
You kick it around,
94 brainwashed puddle scum left on the wall.

Wop cocksucker (-1, Offtopic)

Anonymous Coward | more than 12 years ago | (#2538396)

What do I get if I give you your balls back, you wop cocksucker?

Good to see Lisp is still around. (4, Insightful)

Anton Anatopopov (529711) | more than 12 years ago | (#2538248)

As long as these languages are kept alive by their dedicated users, there is always the chance that the suits will see the light, and go for the productivity gains offered by high level languages.

I have never recovered from learning Smalltalk as a postgraduate, and then being forced to take a job programming in C++ because corporations are so far behind the times.

I look forward to the day when programmers in large corporations are able to use high level languages such as lisp, scheme and smalltalk instead of the current crop of low level languages like C++ Java and Perl.

Re:Good to see Lisp is still around. (1, Informative)

Anonymous Coward | more than 12 years ago | (#2538341)

It's not just the language. Smalltalk was extensively adopted by JP Morgan in the early '90s. APL was used by Morgan Stanley. UBS even attempted to create their own language, 'K'.

But despite all of these efforts, Wall Street continues to use C/C++, VB and Java. Why?

Re:Good to see Lisp is still around. (0)

Anonymous Coward | more than 12 years ago | (#2538381)

Programmer demand, maybr?
Speaking of Wall Street, look at the most effective programming shops. Are they using Smalltalk, APL, UBS? No, their using C/C++, VB, and Java. Surprised?

Re:Good to see Lisp is still around. (2)

connorbd (151811) | more than 12 years ago | (#2538796)

APL? Ugh... You want some real fun, though, take a look at BANCstar [geocities.com], which is very possibly the nastiest thing I've ever seen in a commercial setting. /Brian

developers need to see the light, not suits (2, Insightful)

Frothy Walrus (534163) | more than 12 years ago | (#2538379)

As long as these languages are kept alive by their dedicated users, there is always the chance that the suits will see the light, and go for the productivity gains offered by high level languages.

currently high-level languages like Lisp are good for early prototyping and development stages, but lack the library hooks and other trappings needed for real, industrial strength application development. what i'd like to see Lisp and Smalltalk and Eiffel develop is a good compiler and a good interface to the system and GUI code.
(no, Java does not cut it.)

when i can write an app in Lisp and still use GTK, Athena widgets, etc, then we might see corps moving from C/C++ to languages where memory allocation, etc become fond memories and real high-level thinking may take place.

Re:developers need to see the light, not suits (0)

Anonymous Coward | more than 12 years ago | (#2538415)

what the hell is industrial strength?
Software that is strong like bull and smart like street car?
I've yet to see well written business from a software shop.
Home grown programs are even worse.
The world is awash with terrible software written in every language.

Re:developers need to see the light, not suits (2)

the_2nd_coming (444906) | more than 12 years ago | (#2538422)

lack the library hooks and other trappings needed for real, industrial strength application development

have you looked at python?

Re:developers need to see the light, not suits (0, Flamebait)

rmstar (114746) | more than 12 years ago | (#2538439)

currently high-level languages like Lisp are good for early prototyping and development stages, but lack the library hooks and other trappings needed for real, industrial strength application development. what i'd like to see Lisp and Smalltalk and Eiffel develop is a good compiler and a good interface to the system and GUI code.

Too damn right. And try parallel programing with lisp. There simply isn't such a thing. Sad, sad.

No, hey: I mean it, ok? It is really sad. Tell you more another day.

rmstar.

Re:developers need to see the light, not suits (4, Informative)

sv0f (197289) | more than 12 years ago | (#2538544)

And try parallel programing with lisp. There simply isn't such a thing. Sad, sad.

When you grow tired of sticking your head in the sand, have a look at ITA's [itasoftware.com] website. They make the software that powers Orbitz's [orbitz.com] web site. If this is not an impressive testament to Common Lisp's ability to do industrial strength parallel programming, I'm not sure what would satisfy you.

You are correct that Common Lisp lacks a standard definition of parallel programming constructs, and thus parallel programs must use vendor-specific extensions. (There are some efforts to abstract over the differences.) In this regard, Common Lisp seems in the same boat as most other languages.

Re:developers need to see the light, not suits (1, Informative)

Gabe Garza (535203) | more than 12 years ago | (#2538683)

Too damn right. And try parallel programing with lisp. There simply isn't such a thing. Sad, sad.

There is such a thing. All the major commercial implementations (Franz's Allegro Common Lisp, www.franz.com, Xanalys's LispWorks, www.xanalys.com, Macintosh Common Lisp, www.digitool.com) as well as one of the major free (Free as in honestly free: public domain) Common Lisps support multithreading using largely the same interface.

Re:developers need to see the light, not suits (2)

sv0f (197289) | more than 12 years ago | (#2538485)

currently high-level languages like Lisp are good for early prototyping and development stages, but lack the library hooks and other trappings needed for real, industrial strength application development.

Like what? Common Lisp is as capable of writing 'industrial strength' applications as any other languages. And its dynamic properties mean that you can debug them on-line, without taking systems down for massive recompiles.

what i'd like to see Lisp and Smalltalk and Eiffel develop is a good compiler and a good interface to the system and GUI code.
(no, Java does not cut it.)


Commercial Common Lisp compilers are good enough. What do they lack their C/C++, Java, and other counterparts? (Specific technical features please.)

As far as GUI coding goes, ALL languages but Java seem in the same leaky boat when it comes to developing cross-platform applications. (Java is in its own boat, one with different problems than the rest.)

Re:developers need to see the light, not suits (3, Informative)

Gabe Garza (535203) | more than 12 years ago | (#2538618)

This just isn't true. All major Common Lisp environments, Commercial and Free, offer a painless way to call C functions. No recompilation of any kind needed, you just declare the C function, load the library, and call it.

As for GUI's, there's something called CLIM, the Common Lisp interface manager. It's a standardized Common Lisp GUI. There are at least 4 major implementations. Using it, you can write a GUI application that is Source-code compatible across anything Commons Lisp/CLIM runs on, which includes pretty much any PC operating system as well as a plethora of Unix workstations

In fact, Lisp is ideal for ``Industrial Strength''; application development. It's portable. It's (nearly always) compiled to native code. It offers superb exception handling. It has a package system. You can update running, deployed programs without stopping them. There are many other good reasons.

As for GTK specifically, there are no fewer then 2 Common Lisp GTK bindings out there.

Re:Good to see Lisp is still around. (3, Insightful)

kin_korn_karn (466864) | more than 12 years ago | (#2538657)

C++, Java, and Perl are low-level like my dog is a cat. C is low-level (or with better libraries, mid-level). Anything that supports objects or runs in a virtual machine cannot by definition be low-level because there's too much abstraction of system functionality between the source and object code. Just because C++ still lets you twiddle with bits, doesn't mean you HAVE to.

Productivity is also a huge judgement call. One judges productivity by familiarity; I don't think there's a programmer at my office that knows Lisp (too old), Smalltalk (most are self-taught or consultants), or any of these other obscure languages. Businesses don't choose languages for the 'fun factor'.

cool (-1, Redundant)

Anonymous Coward | more than 12 years ago | (#2538249)

cool

Lithp: not jutht for Gay Nik anymore! (-1, Flamebait)

The_Messenger (110966) | more than 12 years ago | (#2538258)

Would you like to comment on the acctheptance of Lithp in the homosexthual community?

1st p0st (-1, Troll)

Anonymous Coward | more than 12 years ago | (#2538262)

f1r5t p0s7 fuck3r5!

Nice responses (-1, Flamebait)

jayhawk88 (160512) | more than 12 years ago | (#2538265)

But of course the best:

This question actually got scored down to -1 and marked as a troll question, but I fished it out of the barrel and restored it...

Translation: The moderators smoke $3 crack.

Re:Nice responses (-1, Offtopic)

Anonymous Coward | more than 12 years ago | (#2538346)

Jayhawk is that U? Shit, Jerome had some good shit last night for $4. But, damn, man you didn't need to blow him for the 1 doller discount.

More Lisp (4, Insightful)

JustJoking (535170) | more than 12 years ago | (#2538266)

I wish that lisp was focussed on more in CS curriculum. It has far more potential in the future for doing useful things, as opposed to just doing things fast (java).

Re:More Lisp (4, Insightful)

spellcheckur (253528) | more than 12 years ago | (#2538412)

Beautifully, MIT's "intro" freshman CS class, Structure and Interpretation of Computer Programs [mit.edu] is taught in Scheme.

There as been a significant amount of pressure (from both non-CS administration and some CS-because-it-pays-well,-not-because-I-want-to-lea rn students) to change to Java or some other "real world" language, but thankfully, the instructors haven't given in.

The differentiation between good programmers and bad, isn't in the number of languages they "know." Programming is a methodology, and Lisp/Scheme is a great tool to teach it.

Re:More Lisp (3, Insightful)

the_2nd_coming (444906) | more than 12 years ago | (#2538445)

that is the thing I wish Unis would learn. the point of being in school is to learn the fundamentals and the theories, what you do out side school is apply those things you learned to the real world. people should be able to pick up a language, after learning to program, quite easy. If they got a job that requires them to know C++ then they have a good motivation to learn C++.

Re:More Lisp (2)

Pengo (28814) | more than 12 years ago | (#2538441)

Hehe,

My friend who graduated from Harvard said that he wished he learned Java instead of Lisp so he could of learned something he would use in the world.

I know that you learn and take more than details of a language, but his point was not unfounded. Depends on what you go to school to learn and do. Maybe you should choose your school based on your goals in education. His happened to be one that didn't see a lot of value in learning lisp.

Oh well.

Re:More Lisp (2)

sv0f (197289) | more than 12 years ago | (#2538589)

My friend who graduated from Harvard said that he wished he learned Java instead of Lisp so he could of learned something he would use in the world.

Learning Common Lisp as an undergraduate at CMU in the late 1980s changed my life for the better. I guess to each his own.

Then again, isn't one of the goals of a CS degree to expose you to a variety of computational paradigms? Lisp is quite unlike C, C++, Objective C, and the like. Certainly worth a semester or two of exposure.

Perhaps it is your friend that has the problem if all he could handle in college was one freakin' language.

Re:More Lisp (2, Informative)

NetSettler (460623) | more than 12 years ago | (#2538652)

I address this issue in the second part of the interview, to appear in a day or two. In brief, though (for once): I agree, learning more languages (and more kinds of languages) is better than learning fewer. Don't decide between them. Learn both.

one question he didn't answer (-1, Offtopic)

Anonymous Coward | more than 12 years ago | (#2538292)

and i had asked it..

Why do fags all talk with a lisp? I mean, what's the deal?

Is because they suck too much cock, or what? Someone answer me this riddle.

kilohyperlinks (2)

wiredog (43288) | more than 12 years ago | (#2538293)

Whoa. I don't think I've ever seen that before. Or a document where the number of links could be described in that fashion. "Megahyperlinks" sounds cool, though. I wonder if there are any of those around.

Re:kilohyperlinks (2)

sv0f (197289) | more than 12 years ago | (#2538614)

Whoa. I don't think I've ever seen that before. Or a document where the number of links could be described in that fashion.

You should check out Kent's HyperSpec. It's an amazing (and amazingly useful) document. Just project the obvious thoughtfulness of his replies over a huge document and imagine the result.

My god.... (1, Funny)

Cesaro (78578) | more than 12 years ago | (#2538295)

I think I may have just found most verbose man ever. I'm awed by the miniscule size of my scrollbar, and there are hardly any comments! This is ridiculously incredible.

Ah, LISP fanaticism (1, Interesting)

Animats (122034) | more than 12 years ago | (#2538301)

It's been a long time since I've encountered a LISP fanatic. I thought they were extinct.

I've written about 10,000 lines of LISP myself, know John McCarthy (who finally retired last week) and even used a Symbolics refrigerator at one point, but realistically, LISP is an idea whose time has passed.

Representing programs as S-expressions, incidentally, has one terrible cost - it's hostile to comments. Because there's no place to hang the comments, LISP code tends to be uncommented within the text of the code.

He has a good point, though, that while LISP used to be considered a big language, the other languages have bloated so much in the last decade that LISP now looks small.

Re:Ah, LISP fanaticism (2, Insightful)

Brian Kendig (1959) | more than 12 years ago | (#2538378)

I used to be a Lisp fanatic, and I still have a soft spot in my heart for the language. :-)

To me, Lisp is wonderful for three reasons:

(1) It's highly abstract. It makes working with fuzzy concepts (such as natural language) so much easier; you very rarely (if ever) have to get into the nitty-gritty of worrying about how your code actually interfaces with the hardware it's running on. Lisp is one of the highest-level languages I've ever used. Compared to Lisp, C++ is just horribly ugly.

(2) Lisp code can be self-modifying -- it's easy to write a program which puts together a new function and adds it to itself. This makes it great for artificial intelligence, in which self-modifying programs are good things. Compared with this, Perl's 'eval' function is woefully inadequate.

(3) One of the most important things to learn about Lisp is that good code flows from the fingertips, while bad code snarls up and is hard to write. If you're having a hard time getting a piece of Lisp code to work, then you're probably going about solving a problem the wrong way. When thoughts and code are in harmony, it's a very Zen form of beauty.

Lisp code is just *fun* to write. :-) Even more so than Perl code!

Re:Ah, LISP fanaticism (0)

Anonymous Coward | more than 12 years ago | (#2538400)

Representing programs as S-expressions, incidentally, has one terrible cost - it's hostile to comments. Because there's no place to hang the comments, LISP code tends to be uncommented within the text of the code.

Really? It's not the S-expressions fault, for example, in Common Lisp you have ; for comments that reach to the end of the line, #| and |# for block comments (and they nest too) and (this is a bit of a hack) #+ignored for commenting one sexp. Doesn't look like hostile to comments to me ;)

The chief reason the code is often uncommented is the fact that Lisp names tend to be more descriptive and the functions shorter, so you see what's happening without any comments.

Lisp commenting. (4, Informative)

Kaz Kylheku (1484) | more than 12 years ago | (#2538401)

Comments are easily placed in Lisp code. And also, there is a way to embed documentation into functions and some other objects via the documentation string feature. This allows information about a function to be dynamically retrieved. The following illustrates how comments are written in the predominant Lisp code formatting style:

;;;
;;; This function computes the factorial of its
;;; argument x. The argument must be a
;;; non-negative integer. If the argument is 0
;;; or 1, the result is 1. Otherwise the result
;;; is the product (x)(x-1)(x-2) ... 2.
;;;

(defun fact (x) "Computes the factorial function"
(case x

;; if n is zero or 1, return 1
((0 1) 1)

;; otherwise compute factorial recursively
(otherwise (* x (fact (1- x))))))

The comp.lang.lisp FAQ has a few pointers on style, including use of whitespace, comment placement, how many semicolons to use for what comments and the like.

Re:Lisp commenting. (3, Insightful)

NetSettler (460623) | more than 12 years ago | (#2538429)

I think the original poster meant that READ does not preserve comments. This is a true remark, though the idea that it's "terrible" may be a little exaggerated. Most source-to-source transformations don't result in new source files, but are done as part of compilation. No language I know of uses comments (well, ok, PostScript and Teco maybe a little, but by abuse only) to help them compile code, so that's probably a reasonable optimization.

There is a technique one can use for modifying the reader to find comments and attach them to the parent object using hash tables, repatriating them later. I've seen this done for some source-to-source translation facilites such as one provided with the Symbolics system for upgrading user code between releases. It is more work, but given how often the issue comes up, the extra cost is probably reasonable in exchange for how much easier it is to transform code without worrying that comments are intervening.

The alternative is to do like Interlisp did and make comments be structures, but then you can only put comments in certain places. It's plainly more flexible to put them anywhere you want and we pay the cost for that in the READ function.

Re:Lisp commenting. (2)

Phil Gregory (1042) | more than 12 years ago | (#2538680)

I think the original poster meant that READ does not preserve comments. This is a true remark, though the idea that it's "terrible" may be a little exaggerated.

That's not entirely true. While, strictly, comments are diregarded by the interpreter, many Lisp dialects have the conecpt of docstrings, where the first element of a function or structure is a string describing the object's purpose. For an example, let me steal some elisp code from ILISP:

;;;
(defun bridge-call-handler (handler proc string)
"Funcall HANDLER on PROC, STRING carefully. Error is caught if happens,
and user is signaled. State is put in bridge-last-failure. Returns t if
handler executed without error."
(let ((inhibit-quit nil)
(failed nil))
(condition-case err
(funcall handler proc string)
(error
(ding)
(setq failed t)
(message "bridge-handler \"%s\" failed %s (see bridge-last-failure)"
handler err)
(setq bridge-last-failure
(` ((funcall '(, handler) '(, proc) (, string))
"Caused: "
(, err))))))
(not failed)))


--Phil (Gee, I wish Slashdot would let me close the <TT> tag!)

Re:Lisp commenting. (2)

Phil Gregory (1042) | more than 12 years ago | (#2538726)


Gee, I wish Slashdot would let me close the <TT> tag!

Erm, oops. So I had two <tt> tags at the top of my post and only one at the bottom. Preview was showing the monospaced font extending past my </tt>, galeon wasn't showing my the page source properly (it reloads the page to see the source--bad when on dynamically-generated pages), and </tt> isn't in the list of allowed HTML at the bottom. I jumped to a conclusion.



--Phil (Appropriately chagrined.)

Re:Lisp commenting. (2)

ftobin (48814) | more than 12 years ago | (#2538600)

While not trying to put down lisp, it seems like what is desired here is something analogous to Python's docstrings:

class Square(Shape):
"""An abstract representation of a box"""

def size():
"""Return the size of the box"""
return self.x * self.y

The docstrings are queriable (object.__doc__), and there exist excellent tools to give a module/class/method's documention: pydoc. pydoc is such a nice wonder.

IIRC, Python 2.2. has docstrings applicable to object attributes, too.

Re:Lisp commenting. (1)

ftobin (48814) | more than 12 years ago | (#2538658)

Heh, whoops; I forgot that my 'size' method's signature should've been "def size(self):".

your point, deflated (1)

Frothy Walrus (534163) | more than 12 years ago | (#2538405)

(define (f n)
; calculates factorial of n
(if (= n 1)
n
(* n (f (- n 1)))))

there's plenty of room to hang comments...

Re:Ah, LISP fanaticism (1)

andrew cooke (6522) | more than 12 years ago | (#2538427)

That's it? Lisp is no good because you can't fit comments into S-expressions?

A Lisp comment comes after a semi-colon and it's trivial to put one at the end of a line. Also, it's traditonal to write programs as collections of fairly short functions (if you're used to Java or C, for example, the OO part of Lisp breaks the code up into the equivalent of methods rather than classes), so comments above code are also usually visible.

But more than that, why on earth is this rated as 4? Sure, Lisp's time may have passed - but if so, there must be a better argument than that!

Re:Ah, LISP fanaticism (2)

yellowstone (62484) | more than 12 years ago | (#2538451)

Representing programs as S-expressions, incidentally, has one terrible cost - it's hostile to comments. Because there's no place to hang the comments, LISP code tends to be uncommented within the text of the code.
I don't mean this as flamebait or a troll, but what are you talking about? All my LISP code is in text files. It's just as easy (or hard, depending on your habits) to comment LISP as it is to comment Java, C/C++, or any other language with text-based source code.

Re:Ah, LISP fanaticism (1, Insightful)

Anonymous Coward | more than 12 years ago | (#2538476)

Representing programs as S-expressions, incidentally, has one terrible cost - it's hostile to comments. Because there's no place to hang the comments, LISP code tends to be uncommented within the text of the code.

Actually, I believe that LISP provides greater commentability than other languages, since LISP encourages code reuse through small, atomic procedures that can be passed as variables. Need to sort a list based on a metric? Create a generic sort procedure and have it take the metric as an argument. This way, each metric can be documented on its own and the sort routine can be documented separately. At the topmost level, good LISP code becomes very compact and readable as a result of the modularity inherent in the language.

(at lael (dot mit edu))

No place to hang the comments?! (2)

alispguru (72689) | more than 12 years ago | (#2538538)

@ Representing programs as S-expressions, incidentally, has one terrible cost - it's hostile to comments. Because there's no place to hang the comments, LISP code tends to be uncommented within the text of the code. Just curious - when did you stop writing Lisp? If you actually used a Symbolics, how could you have missed the standard semi-colon commenting conventions, which Lisp-aware editors grok quite nicely:

; - inside code (at end of line)
;; - inside code (beginning of line, indented)
;;; - function header comments (column 1)
;;;; - Big block comments

Or have you never heard of the ANSI standard generic function (documentation place &optional type) that lets you access comment strings, which can be hung just about anywhere? I even have a little package I picked up in 1997 that trolls Lisp source code, extracts the documentation strings, and emits javadoc-like documents, in HTML or TeX or RTF.

"no place to hang the comments", indeed.

You might, just possibly, be thinking of Interlisp, which did have a comment form that could be placed inside your function code and was edited with the structure editor like everything else. In ancient times you had to be a little careful as to where you put comments, but that problem went away with Xerox Common Lisp, around 1986 or so.

Re:Ah, LISP fanaticism (2)

sv0f (197289) | more than 12 years ago | (#2538661)

Representing programs as S-expressions, incidentally, has one terrible cost - it's hostile to comments. Because there's no place to hang the comments, LISP code tends to be uncommented within the text of the code.

Actually, quite the opposite. Because Lisp programs have a nested tree structure and there are universal indentation conventions, any single expression in a Lisp program can be isolated on its own line in a way that's natural to the reader, and then commented. Plus, Common Lisp (like all decent languages) permits inline comments: #| comment |#.

Poorly written code in ANY language displays the qualities you attribute uniquely to Lisp.

Are all people with lisp gay? (-1, Troll)

Anonymous Coward | more than 12 years ago | (#2538310)

How does the author dealer with the stereotype that people with lisp tools are gay?

I saw RMS in Cambridge the other day.. (-1, Troll)

Anonymous Coward | more than 12 years ago | (#2538322)

NOT.. LISP is just one of the many "open sores" languages that will be caught up in the big drag.NET over the next few years. I suggest you guys drop the silly scripting languages, install XP, and get with the PROGRAM. The 70's are OVER; put the bell-bottoms away and get object oriented, NOW! That's an order.

Thank you.

Hector V. Gonzalez

Just think... (0, Offtopic)

PW2 (410411) | more than 12 years ago | (#2538331)

He's answered your questions below, at length

I'm imagining Katz hard at work trying to top this one...

C takes too long to write? (2, Interesting)

windex (92715) | more than 12 years ago | (#2538332)

I don't know what planet he's from but, in general, C does not take long to write. C has this wonderful capibility called functions, and if you do a lot of repetitive work, you can write a function to do that repetitive work. Or, for example, in C++ you can pass a class of C++ functions and data as an argument, making it so that modular applications can pass the same code and data to all available functions for immediate use..

IMHO, he's just biased to Lisp, and I'm just biased to C. But, outright saying that C programmers are a bunch of speed-freak-holier-than-thou losers, was going a little far..

Re:C takes too long to write? (2)

mikeee (137160) | more than 12 years ago | (#2538395)

Obviously, "C" is quicker than "Lisp" to write, especially if you already have capslock on. It's shorter.

I predict the new language I am designing, ^H, will be very sucessful.

Re:C takes too long to write? (1)

kill -9 $$ (131324) | more than 12 years ago | (#2538465)

In reading his answers, I have to agree that he is extremely biased towards LISP. I personally was not that impressed with the language at all. However, for writing some AI projects it made for much easier work handling dynamic lists of items which was the only benefit I saw of it.

As I mention in another post in this discussion, I've often wondered if Perl could be used just as easily gaining the benefit and familiarity of writing in a C-like language along with using things like splice/push/pop and other array based notation to handle the lists aspect that LISP does so well.

Re:C takes too long to write? (1)

mdalgarno (448622) | more than 12 years ago | (#2538468)

> IMHO, he's just biased to Lisp, and I'm just biased to C.

The difference is that he backs up such 'bias' with an argument - you don't.

Re:C takes too long to write? (1)

Frizzle Fry (149026) | more than 12 years ago | (#2538509)

C takes far longer to write in for large applications than Lisp due to the debugging time. Tracking down memory leaks, pointer bugs, etc. is a pretty tedious process that lisp programmers don't worry about.

Re:C takes too long to write? (1, Informative)

ingvar (66436) | more than 12 years ago | (#2538720)

One thing I do often when writing C is to have
something *very* similar to this:
[line broken for slightly more readability]
#define EXTEND(BUF, LEN, BUFLEN, TEMP, END) do { while (((LEN)+1)>(BUFLEN)) {
TEMP=realloc(BUF, 2*(BUFLEN));
if (TEMP) {
END=TEMP+(END-BUF);
BUF=TEMP;BUFLEN=2*(BUFLEN);
} else {
write_error(this,
"Malloc fail in support function");
return;}}}
while (0)

I guess I *could* have written a function doing
similar stuff, but I guess it is similar things
that KMP refers to.

Now, I would really like a switch that does
case-sensitive string comparisons, but I don't
fancy writing a CPP macro that can do it for
me. :/

Learning Lisp/Scheme? (2)

FortKnox (169099) | more than 12 years ago | (#2538339)

Anyone have any good docs/books they used to learn lisp/scheme quickly and easily (more than just an amazon/google search)?

Doesn't Lisp have a foundation in AI? Or is that Prolog? Doesn't Lisp somehow have a relationship to prolog?

Re:Learning Lisp/Scheme? (3, Informative)

Pretender (3940) | more than 12 years ago | (#2538397)

The Little Schemer is very good, and somebody can start with that without even having a background in programming.

Re:Learning Lisp/Scheme? (3, Interesting)

Pretender (3940) | more than 12 years ago | (#2538416)

Sorry to reply to my own post, but I forgot one of the best ways to be introduced to Lisp: Emacs. It probably came with your OS or has been ported to your OS at some point, it is based on Lisp (albeit one not as powerful as Common Lisp), and you can get both an introduction to Emacs Lisp and a reference manual direct from GNU's web site.

Re:Learning Lisp/Scheme? (1)

FortKnox (169099) | more than 12 years ago | (#2538499)

Not to start a flame war (this is just my opinion), but in the war of vi vs. emacs, I'm all for emacs. I used emacs while learning C++, and have a great respect for it (although I'm more of an xemacs user).

I remember toying with the idea of learning lisp just to edit emacs to make just a "code editor" and kill all the calender/email/other stuff it has in it (I'm still waiting for the "emacs linux distro", where you login, and are brought to an emacs window that has its own os running. After all it is the only way to increase emacs' bloat ;-) )

Now the next question is, which to learn: Scheme or Lisp? Isn't scheme a newer language? Is it better?

Re:Learning Lisp/Scheme? (2)

sv0f (197289) | more than 12 years ago | (#2538740)

one of the best ways to be introduced to Lisp: Emacs.

Emacs lisp is an old dialect. It differs fundamentally from Common Lisp and Scheme in lacking lexical variable bindings. Avoid it in favor of free versions of the newer dialects if your purpose is to understand Lisp as it has been for the past twenty years. Especially explore Common Lisp, which includes so much cool functionality as part of the standard. For example: I believe that Common Lisp was the first object-oriented programming language to become an ANSI standard.

Re:Learning Lisp/Scheme? (2)

big.ears (136789) | more than 12 years ago | (#2538418)

Lisp is commonly used by AI researchers, more in the 80s than it is today. Prolog is as well, and was the basis for 'Expert' systems that were in vogue a dozen years ago. Aside from the facts that it is fairly easy to implement prolog in lisp, and they are both used by people who are consider AI researchers, they are very different.

From a naive perspective, lisp is just a programming language that you can tell what to do and it does it. Prolog doesn't seem to actually do anything--You just tell it information and it somehow knows the answer.

Re:Learning Lisp/Scheme? (0)

Anonymous Coward | more than 12 years ago | (#2538421)

There is only one book you need to get:

Structure and Interpretation of Computer Programs - also known as "SICP".

Have fun. It is very cool stuff.

Re:Learning Lisp/Scheme? (2)

sv0f (197289) | more than 12 years ago | (#2538772)

Also:

(1) Peter Norvig's "Artificial Intelligence Programming: Case Studies in Common Lisp"

(2) Sonya Keene's "Object-Oriented Programming in Common Losp: A Programmer's Guide to CLOS"

(3) Paul Graham's "ANSI Common Lisp"

(4) Paul Graham's "On Lisp: Advanced Techniques for Common Lisp"

(5) Friedman, Wand, and Haynes's "Essentials of Programming Languages"

Re:Learning Lisp/Scheme? (1)

kill -9 $$ (131324) | more than 12 years ago | (#2538434)

Books, I can't really help you. I learned Lisp out of some book that I'm sure is now out of print , but was titled something like Common Lisp: Programmers Guide or something. It was good, but ancient in computer book years now. (then again I don't think LISP has changed all that much). As for your other questions...

Lisp is used for AI because it makes easy work of slashing through lists of items, etc. (I can't go further since its been a while since I've done AI and LISP) It can also be used for all sorts of other programming tasks, etc. I've often wondered after learning Perl soon after, if Perl could actually accomplish all the great stuff LISP is used for just as easily. Anybody know the answer?

As for Prolog its also used for AI, but I'm pretty sure its a AI specific language (I'm sure it can be twisted to do other things though).

One of the main differences between the two, if memory serves correct, is that LISP is ones a forward chaining language whereas the other is backward chaining (or vice-versa). Again if memory serves me correctly these have to do with deduction and learning. So as far as I know, no they aren't that related.

SICP is what you want (1)

Frothy Walrus (534163) | more than 12 years ago | (#2538436)

Structure and Interpretation of Computer Programs [mit.edu] is probably the best computer science text ever written (with the possible exception of Knuth's Art of Computer Programming), and uses Scheme. it's such a small language (14 basic reserved words, i think?) with such clear syntax that little time is spent teaching the language, and more time is spent teaching programming.

after reading SICP, it will take you perhaps a week to learn any computer language. highly recommended.

Re:SICP is what you want (1)

brsett (169637) | more than 12 years ago | (#2538649)

after reading SICP, it will take you perhaps a week to learn any computer language. highly recommended.

Now, now, a little hyperbole is fine, but this is silly. Many, many (,many!?!) languages develop their expressiveness via keywords and complex idioms, rather than functional constructs and take much longer than a week to learn (I consider someone who has learned a language to be able to write any program they normally could in that language). This is not a bad thing, its just different. Languages such as C++ and especially Ada use keywords to denote many things about the program that languages such as lisp do not bother to enforce, or use convention instead (as far as it goes C is a quite simple language syntax wise, but many of its most powerful idioms could not be learned in a week).

Re:SICP is what you want (1)

NetSettler (460623) | more than 12 years ago | (#2538686)

If you like keywords rather than pure functional programming, you should be checking out Common Lisp, not Scheme. This is a major political difference between these two very different Lisp-family languages.

This issue is discussed in more detail in part 2 of the interview, expected out in a day or two.

Re:Learning Lisp/Scheme? (1)

brsett (169637) | more than 12 years ago | (#2538471)

I've got one just called Common Lisp, 3rd Ed. Not great, but not bad. The Paul Graham one is really, really good. Maybe one of the best books on a programming language I've seen. I think the name is simply ANSI Common Lisp. Highly recommended (check the reviews at Amazon I guess to make sure I'm not off my rocker).

Re:Learning Lisp/Scheme? (1)

lars_stefan_axelsson (236283) | more than 12 years ago | (#2538573)

Well I don't know about "quickly and easily", but the book for Scheme (or rather for programming, but based on Scheme) is: The Structure and interpretation of computer languages", by Abelson and Sussman, MIT Press. It's even online [mit.edu].

While I would certainly recommend some programming background, and perhaps The little Schemer. (Many more tips on www.schemers.org [schemers.org] even a few worthwhile tutorials online such as "Teach yourself Scheme in fixnum days"). SICP as it's affectionately known is one of the best books on programming, period. It may not be in the "teach yourself xx in n days" category, and rather heavy going at times, but the rewards are worth it.

This is IMHO the book that makes Scheme worthwhile.

Re:Learning Lisp/Scheme? (2)

sv0f (197289) | more than 12 years ago | (#2538714)

Anyone have any good docs/books they used to learn lisp/scheme quickly and easily (more than just an amazon/google search)?
Check out the Association of Lisp Users [lisp.org] web site for references. I believe Dave Touretzky has made his very good introductory book available online and Dave Lamkins has also written a long web-based tutorial.

Also, the introductory course at MIT uses the fabled 'Structure and Interpretation of Computer Programs' which I believe is also available online. It covers Scheme, not Common Lisp, though.

LISP sucks... (-1, Offtopic)

Anonymous Coward | more than 12 years ago | (#2538347)

...but not as embarassingly so as, say... Perl.

I'm a happy IT drone (0)

Anonymous Coward | more than 12 years ago | (#2538625)

Perl had sucked. His wife hadn't.

God, he was beat at every turn. Frustrated at every corner. No good thoughts or beautiful visions before the moment of truth. Only blackness, a life of dull, planned movements as consistent and boring as a bran-concious geriatrics bowel movement. For a moment he thought he might cry.

AKKKKK! My Brain! (-1, Offtopic)

Anonymous Coward | more than 12 years ago | (#2538348)

Whoa, heavy reading that was. I need an aspirin now.

add it to the list.. (-1, Offtopic)

Anonymous Coward | more than 12 years ago | (#2538391)

LISP is dying !!

AHH!!!!! (1, Offtopic)

the_2nd_coming (444906) | more than 12 years ago | (#2538403)

I have never seen LISP before, now that I have, I have a very strong respect for those that can actual think in the the LISP way........

how can you write a math formula like that!!!!
my brain hurts......

Re:AHH!!!!! (2, Informative)

andrew cooke (6522) | more than 12 years ago | (#2538443)

You get used to it ;-)

Seriously, it becomes natural. Just like using RPN HP calculators (which is kind of similar)

Re:AHH!!!!! (2)

sv0f (197289) | more than 12 years ago | (#2538790)

how can you write a math formula like that!!!

You should see how Lisp folks wretch when they seem the horrors the **ML crowd has foisted on the world.

Aren't you tired of serving Lord infix and the dark side, Darth? ;-)

Lisp Not Hard (2, Informative)

Putz19 (202601) | more than 12 years ago | (#2538410)

I learned CLISP during my last semester of College in my AI class(to ('01 Jan) ('01 May)) [Jan '01 to May '01]. I did not think it was all bad, the worst was making sure you have the right amount of ()'s matching.. This was solved with the ALMIGHTY VIM!! This handy editor color coded my code and made working in files a snap, also with the % command to see matching ()'s.

Just My CS 2 cents.

Re:Lisp Not Hard (2)

Evangelion (2145) | more than 12 years ago | (#2538500)


If you think that vim is nice for lisp editing, try emacs.

Being able to send the current expression to the lisp interpreter with a keystroke to see if it evaluates correctly is awesome once gotten used to ;)

Re:Lisp Not Hard (1)

Dom2 (838) | more than 12 years ago | (#2538693)

Well, it's easy to get paren-matching emacs as well. I think it's turned on by default. But one more useful hint is to make the % key behave the same as in vi. This bit of elisp code does the trick.

(defun match-paren (arg)
"Go to the matching parenthesis if on parenthesis otherwise insert %."
(interactive "p")
(cond ((looking-at "\\s\(") (forward-list 1) (backward-char 1))
((looking-at "\\s\)") (forward-char 1) (backward-list 1))
(t (self-insert-command (or arg 1)))))
(global-set-key "%" 'match-paren)

MOO! (2)

scrytch (9198) | more than 12 years ago | (#2538417)

If I'd known you programmed in MOO, I'd have asked: what's your character name on LambdaMOO?

Anyway, implementing tail calling in MOO isn't as bad as it sounds, and for a trivial case of it, I implemented it. You do lose most of callers(), and thus have less meaningful tracebacks, but I just keep the last frame for caller and caller_perms(). The only thing that permanently breaks is callers() based security like @gag and @refuse, but I implemented a "taint" mechanism (in-db, could easily have been done in-server) that just held the set of perms used. gag_p was then a simple matter of $set_utils:intersection(this.gaglist, permset)

Sometimes wish I still had my old MOO code, but I gave up on MOO long ago after seeing that it just wasn't going to get anywhere. Shame I don't see any real languages anymore with integrated security like MOO had.

Comparison with ML/OCaml (2, Interesting)

Random Man (209046) | more than 12 years ago | (#2538469)

I would love to hear Kent Pittman compare Lisp with the growing interest in quasi-functional languages such as ML and especially OCaml.

These languages give up the s-expression syntax, and thus the powerful Lisp macro facility which people like Paul Graham believe to be critical to high-end Lisp programming.

What they offer in return is static type checking, which has saved me countless hours of bug hunting, and some wonderful mechanisms for abstraction and code clarification: sum types, modules, functors, and exceptions.

I used to do all my work in Lisp/Scheme. And occasionally I miss the simple clarity of the s-expression syntax and the macros. But these days I do everything in OCaml and have been amazed at the ease with which conceptual structures become code.

Re:Comparison with ML/OCaml (3, Informative)

NetSettler (460623) | more than 12 years ago | (#2538478)

I think there are some remarks on this in the second half of the interview. Maybe re-ask this question in response to that?

Sorry the interview got split. There was apparently a length limit, perhaps caused by a pre-allocated fix-length buffer due to failing to use a language with dynamic memory allocation. ;-)

Re:Comparison with ML/OCaml (1)

chromatic (9471) | more than 12 years ago | (#2538698)

Close... it's a database field size limit. (Perl has dynamic memory allocation, but you knew that. :)

python v lisp (0)

Anonymous Coward | more than 12 years ago | (#2538490)

I used to love lisp (well, scheme more so) but then I got into Python and I havent looked back. Hello world in python, at it's easiest, is

print "hello, world"

I think thats the first thing that won me over, the 2nd was that it was all infix, which in my heart, i love better than prefix, and 3rd would have to do the lack of syntax structrures... not a ton of parents or other things around, but rather indenting... pretty nice.

Help me start learning (0)

Anonymous Coward | more than 12 years ago | (#2538546)

I've been trying to follow the online tutorial found at lisp.org, but I get stuck at the hello world example (Pretty discouraging). When I try:
(write-line "Hello, world.")
I get: "Symbol's function definition is void: write-line"
Is there a library I need to load into emacs (how do I do that)? Any help will be appreciated.

Scheme isn't dead? Then it should. (0, Flamebait)

DaaZ (473014) | more than 12 years ago | (#2538623)

I say scheme because it's what I'm learning right but it could easily be extended to LISP in general.

The language has it's potential and I guess part of the reason why I hate it is because my scheme teacher is a complete moron who's exams are about verifying our ability to be a scheme interpreter.

But anyway I think it's an archaic language (it was invented in the 50's if I recall) and like anything invented nearly 50 years ago in the computer world, something better has evolved from it or was either created from scratch in a better way.

I hate the gazillions of parenthenses and especially the poor interface given to me by DrScheme (of course again there might be something better but it's our teacher's restriction).

I also don't think the language would have survived if it was not supported by universities morons who just don't want it to die. Leave it be! It's time is over!

Anyway... speaking about speed. We had a small project of doing fractals and compared it to a c++ program and the scheme program took nearly 20 times than the c++ to do the same recursion level.

So don't talk about nanoseconds here, we're more talking about days and months faster with a c++ program. (Btw the c++ prog took me 5 minutes to write while the scheme took me nearly 2 hours. Of course I'm advanced in c++ and was beginning in scheme but still, there's too much fighting with the language itself).

So in final words. Carry on. Nostalgia and the computer don't mix too well, once something is too old (and scheme was too old maybe 20 years ago...) drop it and go on to something else.

Re:Scheme isn't dead? Then it should. (5, Informative)

Gabe Garza (535203) | more than 12 years ago | (#2538779)

But anyway I think it's an archaic language (it was invented in the 50's if I recall) and like anything invented nearly 50 years ago in the computer world, something better has evolved from it or was either created from scratch in a better way.

Lisp has evolved. ANSI Common Lisp is a very different language then what was used in the 50's. It has been continously evolving for nearly half a century.

I hate the gazillions of parenthenses and especially the poor interface given to me by DrScheme (of course again there might be something better but it's our teacher's restriction).

Nearly all serious Lisp development is done in an Emacs-like editor that has built-in support for writing Lisp programs. This support includes facilities that make keeping paranthesis balanced trivial.

I also don't think the language would have survived if it was not supported by universities morons who just don't want it to die. Leave it be! It's time is over!

I'd highly recommend you go to www.lisp.org and look at the hundreds of huge commercial applications that have been written in Common Lisp. It is not an obscure research language: If Common Lisp was only used by ``universities morons,'' would 2 major vendors (www.franz.com, www.xanalys.com) be able to make money off it? Incidently, both the preceeding sites--especially www.franz.com--list commercial customers who have been satisfied with developing software in Common Lisp.

Anyway... speaking about speed. We had a small project of doing fractals and compared it to a c++ program and the scheme program took nearly 20 times than the c++ to do the same recursion level.

It's very important to note that Scheme is not Common Lisp. Scheme is a very different language: Scheme is about having an elegant tool to solve problems; Lisp is about having a tool to elegantly solve problems. In particular Common Lisp is typically compiled to native code and allows the programmer to include type declarations. These two features alone can improve speed by a couple orders of magnitude. To be fair, some Schemes support these features but, AFAIK, it's not standardized.

Lisp/Scheme implementation (1)

mystik (38627) | more than 12 years ago | (#2538735)

Here @ NEU, some professors are part of 'TeachScheme', which is an effort to push Scheme into CS curricula. They have actually put togeather a scheme implementation, DrScheme, which provides an excellent interactive environment for writing and learning scheme http://www.cs.rice.edu/CS/PLT/packages/drscheme/ [rice.edu] Oh, and it's GPL too. runs on Mac/Windows/linux.

syntax nothing to be proud of (2, Interesting)

ezekeze (451493) | more than 12 years ago | (#2538764)


The thing I personally like about (+ (* 2 y) x) rather than 2*y+x is that it simplifies my editing.

Abd then bragging about how easy it is to write editor macros to manipulate expressions? some of the examples ended in lines like:

(string &lt (first-name name1) (first-name name2)))))))


Crapping closing parens like that makes the language difficult to read without a text editor for matching. And it hurts my eyes ;-).

If Lisp is so great, why isn't it more popular (3, Interesting)

scruffy (29773) | more than 12 years ago | (#2538780)

Long ago and far away, I programmed on an Xerox Lisp Machine (Dandelion) for several years and immensely enjoyed it, so my comments are intended to be friendly rather than hostile.

While weak typing and dynamic scoping are great for some things, it really trips up a lot of beginner programmers. An alternative Lisp that requires declarations might be very helpful for beginners. For strongly typed languages, compilers are a major help in debugging.

I would agree that other languages have become huge, I think the problem is that Lisp is a big and idiosyncratic language. Some things are in Lisp because of tradition. Some more things are in Lisp because they were grafted on top of the tradition. Then you have exceptions such as macros that violate the usual rules. It is true that Java is also huge, but each object in the API follows a very restricted syntax.

CLOS has all sorts of interesting things in it such as multiple inheritance and methods for combinations of objects. These are very nice once you have learned to use them, but there are lots of pitfalls, too.

I guess this means Lisp is a power tool for those who have learned how to use it. But it is difficult to learn, and unfortunately, a widely-used and widely-understood (more or less) language needs to appeal more to the lowest common denominator rather than only to those that get it.

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