Seven Languages and a few questions

Pragmatic Programmer has published Bruce Tate's Seven Languages.  I have some reservations.

The languages are Clojure, Haskell, Io, Prolog, Scala, Erlang, and Ruby.  Looks cool.  But look again.

Clojure is something of a Lisp reincarnate.  Io and Ruby are botrh Smalltalk in another guise: Ruby is Smalltalk in files à la Perl; Dekorte's Io is Smalltalk-2 (Self) + actor (but not morphic - for which see one brand of Squeak Smalltalk.)

Erlang is best understood as Prolog reduced.  So what would have been beyond 1974 Prolog? Oz.  Or Mercury.  Or XSB.  Or think outside the box with a chapter on Logtalk instead.

Scala Traits come from Squeak Smalltalk, btw.

I have no quarrel with Haskell being there, though some would argue for OCaml.

But if LISP is not there, what is Prolog doing there?  Why not JESS or Drools instead?  And not a single expression-based language (Rebol, ICON/UNICON ( and now ObjectIcon and Converge) or MIT Curl, the language (ww.curl.com.)

With Ruby there, we at least have a reminder that performance matters - so maybe it should have been JRuby.  But I can imagine how Pythonists might feel incensed.

I would suggest 12 languages in 12 months or 3 languages in 3 months.

Take a moment to look at the comments on the Prolog N-Queens code.  Is Tate claiming that the two files in question are his copyrighted code?  Compare the ICON code for N-Queens and ask whether you wouldn't be better looking there for an alternative language on your shelf.  And Rebol 3 is really starting to take shape over at Rebol.net, Rebol.org and Rebol.com

Most CS folks recall the course in which they were required to do some Prolog.  But would they skip a chapter on JESS or Logtalk?

The real story in Prolog in the past 25 years is constraint resolution, and that can be seen best in Oz.  But the reader will have to use emacs.  Oops.

I don't mean to knock Amzi! Prolog for Eclipse or many of the excellent Prolog projects such as swi-prolog.org (now with UNICODE and constraint-handling rules) but I would argue that what makes SWI interesting is Logtalk - and if there is RDF in the picture, that points to XSB.

Clojure, Haskell, Io, XSB, Scala, Erlang, JESS and JRuby in 8 weeks.  Ok, now I'm more likely to recommend a book.

"Clojure, F#, Io, Oz, Scala, Erlang, and JRuby in 7 months".  Call it "between vacations reading-and-testing-and-coding-and-designing".  And you would have my attention.

And whatever became of Tcl ( it only gave us Tk, Expect, Sqlite and now TclOO.)  Oops.

Oh, and Mercury now generates Erlang in addition to C or Java.

PS
Isn't concurrency coming to UNICON?  Isn't Oz now distributed Oz?  Isn't ObjectIcon at code.google.com/p/objecticon
Oh - right.  The cool factor.  And Smalltalk itself - after giving us so much and then the RefactoringBrowser and then UnitTest and pair-programming and eXtreme Programming and the wiki at c2.com ... is not yet cool again.  Might as well wait for Hermes2 on a non-Linux OS.
Oh - and Rebol is already PEG-equivalent at 300+ Kb core running with a claim to a whole 15 Mb of working memory.  Hmmm.

Visual Prolog 7.3

Prolog Development Center has just released version 7.3 of Visual Prolog.

VIP was once known as Borland Turbo Prolog and was one of my favorite tools alongside Borland C++ for OS/2.

PDC Prolog has its counterpart in the Mercury project: a typed Prolog.

So what is new in 7.3? Well, Visual Prolog is getting ready to go 64-bit.  That and more are detailed at the 7.3 page.

For a while I thought the Prolog would go behind the scenes at PDC as it did when Air Liquide acquired Prologia in France (the home of Prolog IV as CLP.)   Happily PDC now is back to showcasing at least AI and not just smart software applications.

But what will the fate of this Prolog prove to be?  In a decade or two, projects such as Oz and Mercury may be in other hands - but a small commercial venture?

In my experience the strength of Visual Prolog was not the IDE or the GUI-building tools but the debugging.  And that has been further strengthened in the 7.3 release.

There is a "personal version" available for download and extensive examples come with it.

Prolog is part of the Adobe world in the ILOG arena (an IBM acquisition) and in an age of multi-processor 64-bit hardware, Prolog should come into its own in the RDF processing needs of the semantic web (in which regard, see Logtalk and the XSB project as well as http://www.swi-prolog.org/ for alternatives to PDC.)

A typed-Prolog should present no problem to ActionScript Flex developers at home with a typed ECMAScript variant - and "declarative" MXML UI layout.

Other languages superbly suited to processing text: ObjectIcon, Icon 9.5, Rebol, Oz.

Other Prolog implementations of merit: Eclipse-housed AMZI! Prolog.

For OOP for almost any other Prolog than PDC, see http://www.logtalk.org/

When the ICON language was named, Ralph Griswold could not have suspected that computing would come to have an "iconic" interface.  Curl has suffered a similar fate due to haxx.se and cURL.  Sadly, XML has a "prolog" and not a "prologue" so without RDF, searching for news on Prolog and XML is vexing.  So far, Rebol fares best and Oz much better.  As for Mercury and Alice, what's in a name?

http://www.logiquewerks.com/index.html

What's new in what was once Borland Turbo Prolog?

PDC Visual Prolog has a page on what's new in 7.2

What stood out for me was anonymous predicates or "nameless clauses" as the Prolog response to "anonymous functions".

If you are interested in Tokyo Cabinet, you might want to glance back at PDC over the years and their features offering internal and external databases.  While I have been more excited about XSB and Logtalk in recent years, I have always enjoyed working in PDC.

There is something of an equivalent PROLOG in the Mercury project: both are distinctive in having a type system and in how they track determinism.  Both PDC and Mercury would like to appeal to programmers with a hankering for a functional style.

There are many active Prolog projects: the SWI-Prolog project is likely the most active in opensource and offers RDF parsing - somewhat different from that offered by XSB.

It is odd that with all the interest in Joe Armstrong and Erlang that there seems to be no up-tick in interest in Prolog and Constraint Logic Programming: the acquisition of ILog by IBM and the move of Drools into JBoss seem not to float any other boats.

Like Prologia (Prolog IV) in France, PDC now focuses on their software application offerings and not the language - but you wonder what would have happened if Apple or Microsoft had offered a Prolog to compete with Borland back in the late 80's ... but you could say the same of Smalltalk (in fairness, Apple's Objective-C is like Smalltalk and for some time Apple was home to some Smalltalk researchers.)  At least PROLOG never suffered the fate of Self and Strongtalk at the hands of SUN.

PDC was an early advocate of DSL's (Domain Specific Languages) but I do not know if these feature prominently in their own commercial packages.

Meanwhile, over at Strawberry Prolog a Windows prolog has been in a Beta for version 3.0 for almost a year: it was to contain a major innovation in the design of Prolog compilers, but I am still back at 2.9.2

If you like Eclipse, you might like AMZI Prolog 8 which comes as an Eclipse environment.  Amzi! is a pleasure to use and has great documentation if you have been away from logic programming for awhile.  But there are other options for Prologs which interface with Java and many "small" prolog interpreters about. 

One way to glimpse which Prolog implementations are active is to see which are supported by Logtalk - but that would exclude some of those which come with their own OOP frameworks .. such as PDC.

For other recent changes in PROLOG, see xsb.com and XSB at sourceforge.

If you are tracking any other PROLOG innovations, please add a comment and a link.  I have a note on Distributed Oz 1.4.0 elsewhere ...