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Who killed Prolog?

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Re: Who killed Prolog?

#21

Post by adamo »

parenthesis wrote: post #17
silentbicycle wrote: post #14

Prolog isn't dead, it just doesn't seem to get a whole lot of attention these days. I use SWI-Prolog for prototyping and exploratory programming, and I didn't need a shovel and a lantern to install it. I don't think Prolog is practical as a fully standalone language, though. Like SQL, it has a model that strongly skews it towards certain kinds of problems, and which makes I/O and side effects awkward. I think it woul…

Re: Prolog implementation, in case you haven't already found it, the book Warren's Abstract Machine: A Tutorial Reconstruction , by Hassan Aït-Kaci, is pure gold for understanding the WAM. http://web.archive.org/web/20030213072337/http://www.vanx.or...

Easier link http://wambook.sf.net/

Re: Who killed Prolog?

#22

Post by parfe »

I tried learning prolog. I had a class on it in college and it never really clicked. Then a tutoring gig fell into my lap a few years later for the same class and I ended up getting "it". And even then it wasn't worth any additional exploration. I learned python and pay my bills.

Re: Who killed Prolog?

#23

Post by arethuza »

wlievens wrote: post #13
derefr wrote: post #9

What people wanted Prolog to do, it couldn't do. People wanted to step away from the control flow specification of imperative language, the message-passing of OOP, and let the compiler solve your problem for you by feeding it a specification of the constraints the completed system would follow. Prolog did not, and cannot do this, because it is not strong AGI. When people realized this, they gave up on it, because it…

Very much true. During my education I was massively disappointed in Prolog, because the programming process was something like this: 1) write it declaratively 2) figure out that your program will take days to complete 3) add ugly procedural hacks (cuts) to make it more efficient To an extent, you have this process in any language (write->measure->optimize) but typically not in a way that it forces you at gunpoint to…

An excellent point - Prolog fans (usually those who never actually programmed anything) would describe it as a declarative language.

However, any "real" Prolog program that I ever saw was really using it as a slightly odd procedural language.

Re: Who killed Prolog?

#24

Post by terra_t »

One of the first things that the FGCP did was discover that Prolog wasn't parallelizable the way they had hoped: very quickly they switched to a language called KL1 (very different from KL-ONE) that was parallelizable.

I'm amused at the general supposition that the FGCP was a failure. Yes, it failed to produce specific hardware that was commercially competitive, but the basic program of "applying parallelism to search and database tasks" behind it was the basis for Deep Blue, Google's web search and the infrastructure behind many a large scale system.

Re: Who killed Prolog?

#26

Post by igrekel »

derefr wrote: post #9

What people wanted Prolog to do, it couldn't do. People wanted to step away from the control flow specification of imperative language, the message-passing of OOP, and let the compiler solve your problem for you by feeding it a specification of the constraints the completed system would follow. Prolog did not, and cannot do this, because it is not strong AGI. When people realized this, they gave up on it, because it…

You mean something like Cyc or Open Cyc? http://www.cyc.com/opencyc/

I am not sure that I fully agree. Even without that, Prolog is very useful for many problems.

Re: Who killed Prolog?

#27

Post by mark_l_watson »

That was a fun read, especially the history of Admiral Inman setting up MCC. He was on the board of directors for my company and for years I had to pitch to him and a small committee to get IR&D funds. I also got a brief tour of MCC from him when it was getting set up. He was in a really good mood because he had just arranged the hire of Douglas Lenat.

As mentioned in the article, Feigenbaum's and McCorduck's book on the Japanese 5th generation project had caused quite a stir in the USA, and I think that it made it easier for me personally to get IR&D funding for anything AI-ish.

Perhaps off topic: I view Prolog as almost a scripting language because most programs I wrote in Prolog were short and solved one little problem. The only long Prolog program I every wrote was a quick one week rewrite of a 5 week IR&D project that was a prototype battlefield simulator that I wrote in Lisp. I can't imagine writing a million line system in Prolog.

Re: Who killed Prolog?

#28

Post by davidmathers »

ionfish wrote: post #3

Not to nitpick overmuch, but if functional, object-oriented and logic are the other styles of programming language, then surely the correct adjective to describe Fortran is procedural ? Object-oriented languages are also generally imperative—the contrasting term is declarative, which purely functional and logic programming languages are (to some extent). Interestingly, given the conclusions reached in the article, bo…

surely the correct adjective to describe Fortran is procedural

No, the original FORTRAN that the author is referring to wasn't procedural. FORTRAN II, a few years later, added subroutines to the language.

Re: Who killed Prolog?

#29

Post by sharkbot »

silentbicycle wrote: post #20
wazoox wrote: post #18

Earlier quoted context omitted.

> I think it would be best to have a Prolog-like language > as a library (like Lua or SQLite), to embed it for rules > & scripting. You may be interested to know that there are various prolog Perl modules on CPAN, particularly AI::Prolog and Language::Prolog::Yaswi .

Perl isn't really my thing* , but I'll take a look at how they're implemented. I was thinking a C library with a C API that will make it easy to use from Lua, Python, Ruby, etc. Yaswi is probably just a wrapper to SWI-Prolog. There are a few of those, and I'm tempted to write one for Lua. I think designing a Prolog-like language primarily for embedding, rather than wrapping a standalone Prolog, will have an interesti…

Check out js-prolog: http://ioctl.org/logic/jsprolog-history

It's a quick-and-dirty implementation of a Prolog interpreter, but it's a great resource for prototyping. JavaScript ports very well to Lua, so you should be able to port the code in a busy afternoon.

I made a couple of suggestions to increase the speed of the interpretation, but I'm not sure Jan ever integrated them into the code. The big one was using a trace to destructively modify environments rather than recreating them on choice points; WAM and tabling would be great, but it's a non-trivial piece of work following Warren's tech report, even with the help of the (very good) tutorial.

Re: Who killed Prolog?

#30

Post by silentbicycle »

sharkbot wrote: post #29
silentbicycle wrote: post #20

Earlier quoted context omitted.

Perl isn't really my thing* , but I'll take a look at how they're implemented. I was thinking a C library with a C API that will make it easy to use from Lua, Python, Ruby, etc. Yaswi is probably just a wrapper to SWI-Prolog. There are a few of those, and I'm tempted to write one for Lua. I think designing a Prolog-like language primarily for embedding, rather than wrapping a standalone Prolog, will have an interesti…

Check out js-prolog: http://ioctl.org/logic/jsprolog-history It's a quick-and-dirty implementation of a Prolog interpreter, but it's a great resource for prototyping. JavaScript ports very well to Lua, so you should be able to port the code in a busy afternoon. I made a couple of suggestions to increase the speed of the interpretation, but I'm not sure Jan ever integrated them into the code. The big one was using a t…

Thanks! That looks fun.

I'm planning on doing a C VM-based implementation with tabling* . I'm not sure about coroutines, and the VM will not necessarily follow the WAM design verbatim - Peter Van Roy has several suggestions for improvements in his thesis.

* Prolog-ese for memoization

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