The Slate Programming Language

An anonymous reader writes "I know that we have had an influx of new programming languages of late, but I feel that this one merits special attention. Theoretical computer scientists and long-time Squeak and LISP contributors Brian Rice and Lee Salzman have been rapidly developing a language called Slate. It draws on the various strengths of the Self, Smalltalk, and LISP languages. To quote from the website: 'Slate is a prototype-based object-oriented programming language based on Self, CLOS, and Smalltalk. Slate syntax is intended to be as familiar as possible to a Smalltalker, rather than engaging in divergent experiments in that respect.' The beta release is currently being written in Common LISP."

Comments

It works!

[Timesprout]

I prototyped this mail using it

Ah, great, Smalltalk

[Deraj DeZine]

Slate syntax is intended to be as familiar as possible to a Smalltalker

And for the rest of the world? Oh wait, sorry, Smalltalkers are gods among programmers. So foolish of me to think of myself before the Smalltalkers.

Re:Ah, great, Smalltalk

[hding]

I suppose the rest of the world can take the five or ten minutes that it takes to understand Smalltalk syntax.

Re:Ah, great, Smalltalk

[Mjlner]

Slate syntax is intended to be as familiar as possible to a Smalltalker

So it is definitively not going to be very popular in Finland. The Finns are known as the worst small talkers in the world.
Oh, wait...

Re:Ah, great, Smalltalk

[Anonymous Coward]

Great, indeed. I'm always amazed by comments like this. How on Earth a language designed to be easily used by small children ever acquired this lofty "ivory tower" connotation I doubt I will ever know. I've been a professional Smalltalk programmer for the last ten years. The language is literally child's play, working with it is easy and enjoyable, building large complex systems with it is trivial, maintaining them is also rather painless, the tools that are typically bundled with it are incredibly powerful, the tools I've built to go along with it have been easy to build, the community itself is very friendly. I've never come across this attitude that you describe. There are some very sharp people in this community, I would assume that there are some very sharp folks in other language communities as well. As for myself, I've never considered myself to be a master programmer, but as one person put it, "the power of Smalltalk is to allow mediocre programmers to create powerful systems". Not exactly flattering, but there is a lot of truth in that. It certainly makes my life a great deal more enjoyable. The simple truth is that most programmers, whatever language you consider, are not gurus. Never underestimate the power of a computing environment that began with the notion of giving end-users power equal to that of those who created the environment. It lets ordinary programmers such as myself look good on a daily basis.

Re:Ah, great, Smalltalk

[platypussrex]

In grad school our compiler class had to write a basic C compiler (standard fare I know). Was a good learning experience and all that (actually I wrote mine in Macintosh Pascal just to freak the professor!) Then in a course in OOP the class did a group project to create Smalltalk (only got about half of what we wanted done... that's the nature of groups I think) Was my first exposure to Smalltalk and to OOP and really liked Smalltalk. Have always thought that students getting their first exposure to OOP would be much better served using Smalltalk than C++

Later a graphics class was done almost entirely using Smalltalk (by a visiting professor) and people from previous years were amazed at everything we got done. Never had a chance to program in it professionally, but many good memories of it. Have never had a slightest sense of elitism etc from those using it either.

Re:Ah, great, Smalltalk

[saunabad]

Oh wait, sorry, Smalltalkers are gods among programmers.

Indeed. They are mentioned frequently on the literature, but no one has actually seen one living and breathing. :)

Obligatory.

[hot_Karls_bad_cavern]

If the new language doesn't support your needs, shut up and don't use it.

Use what is best for the situation and don't whine.

Re:Obligatory.

[11223]

Sure. I'm not good of thinking of Haskell and Smalltalk examples, but since I know Lisp, I can throw out a few. If you've:

• Played Jak & Daxter or any of its sequels
• Played Abuse
• Booked a reservation on Orbitz
• Visited the campaign web sites of Bill Clinton in '96 or Howard Dean in '04
• Used the Mirai facial-animation software or watched Gollum in Two Towers / RoTK
• Used an AMD processor, parts of whose logic is validated via the ACL2 theorem-prover software
• Used GNU/XEmacs
• Used AutoCAD
• Used the lisppaste pastebot on a bunch of channels on Freenode

You've used or seen a program that was written in a Lisp variant (all but Emacs and AutoCAD were done in ANSI Common Lisp). To find out more, visit CLiki.

Not all the world is a desktop application with a GUI. Lisp and the other languages aren't going away in this space anytime soon. It's just too cumbersome to do many of these things in C++, and too slow to do them in Java (Common Lisp is usually native compiled).

Re:Obligatory.

[11223]

Here you go.

Your use of parentheses there is amusing and sad. You do know that those parentheses denote serialized lists, right? You've just made a list of a list of a list of a ...

Sheesh, learn a little about the language before you go making fun of it.

well,

[bsDaemon]

at least you admit it. that's the first step to recovery.

Too obscure

[Animats]

By paragraph 2 of the manual, we're here:

• Block closures

  A block closure is an object representing an encapsulable context of execution, containing local variables, input variables, the capability to execute expressions sequentially, and finally returns a value to its point of invocation. The default return value for a block is the last expression's value; an early return can override this.

This is a language for people who like obscure semantics.

Yes, closures are useful. I've used them in LISP. I even used one once in production code in Perl, to do some error handling cleanly. But when the manual starts out with closures, it's clear that somebody is getting too cute.

This is a language for "l33t haxxors", of the old MIT AI Lab persuasion. Check out "instance specific dispatch". Now that's designed to totally confuse maintainers.

Re:Too obscure

[Anonymous Coward]

In Smalltalk, closures are fundamental. Without them you can't do if statements or whiles or anything else.. Smalltalk closures are very simple.. in Lisp their are a bit more intimidating to the unitiated.

Re:Too obscure

[Animats]

Well, it's one solution to the "how do I return a temporary" problem. There's elegance there. But it's expressed in an unnecessarily obscure way. The reference-counted Perl model is equally powerful but more comprehensible.

Re:Too obscure

[quigonn]

No, it's not obscure. Please have a look at Ruby, where closures are the natural way of doing most things. For example, there is no for-loop, but it is implemented as method for Integer objects (literals are also objects in Ruby):

14.upto(19) do |i|
# do ... end is the closure
end

so, the closure is executed 6 times, the first time with i = 14, the next time with i = 15, the third time with i = 16, up to i = 19.

Just have a closer look at Ruby, and you will see that the whole standard library is built on top of this simple and elegant concept. The book "Programming Ruby" can even be read online and downloaded from www.pragmaticprogrammer.com.

Re:Too obscure

[be-fan]

Closures are everything! All the crap that modern languages do with special-purpose features, like generators, iterators, etc, can be done with closures. Hell, OOP can be done on top of closures.

right!

[Anonymous Coward]

I C sea Slates on the C Shore!

The first thought that came to my mind...

[Rahga]

Even though, admittedly, this looks is a joke post, I couldn't help but think this the moment I noticed the article: "I don't really need a programming language that hates Catholic, can't grasp the realities of free-market economics, and is determined to write-in Howard Dean on the 2004 elections ballots..."

why slate

[larry bagina]

From the faq: Why did we decide on a new programming language?

• Smalltalk-80 is over 20 years old. We don't think the original team intended for the model to last this long (well, from discussions on the Squeak mailing list, they've said so).
• Smalltalk doesn't adequately express many design possibilities that show up often in good complex programs. Requiring classes, not allowing multiple dispatch, and not including some form of multiple inheritance is limiting for a lot of interesting cases.
• The Common Lisp and Dylan communities have created some powerful interface toolkits which Smalltalk cannot easily take advantage of.
• Cecil is statically-typed and not very dynamic. Dylan suffers from a case of too much syntax, and not enough emphasis on live environments.
• Common Lisp is not object-centered or generic enough with its functions.
• Goo uses the unfriendly Lisp syntax, and isn't quite suited to object-centered thinking.
• Self turned out to be too strange an environment for Smalltalkers, and never had a decent implementation. Strongtalk was bought up.
• Bytecode virtual machines and chunk format are old hat. It'd be worth at least trying some different run-time setup.
• The Squeak system is very powerful in terms of some experimental libraries and user interface ideas, but is based on an aging architecture and a license that is partly troublesome.

i think smalltalk++ would be a better approach than inventing a new language. Look at C++: it's backwards compatable with C, so a C coder is already a C++ coder and can slowly start making use of new C++ features.

Re:why slate

[Anonymous Coward]

"i think smalltalk++ would be a better approach than inventing a new language. Look at C++: it's backwards compatable with C, so a C coder is already a C++ coder and can slowly start making use of new C++ features."

Or maybe, just maybe for once we could acknowledge that programmers are smart people and can learn new things. Lets get off trying to bend over backwards and make a broken language better -and- backwards compatible. This is exactly why C++ is the horror that it is today. Write a new clean language and just make sure that it links well with others. Then you can call functions from your old programs written in whatever the hell language you want, nobody knows and the code slowly moves over to a codebase that doesn't rape the programmer (like trying to use exceptions in a C++ program without the exception killing you!).

Deja vu

[spellraiser]

Slate is a prototype-based object-oriented programming language based on Self, CLOS, and Smalltalk.

From a recent post:

Prothon is a new industrial-strength, interpreted, prototype-based, object-oriented language that gets rid of classes altogether in the way that the Self language does.

Does this point to a trend in language design?

Re:Deja vu

[angel'o'sphere]

What's a "prototype-based object-oriented" language and how does it differ from C++ and Java?


In Java and C++ you have classes. In a prototyped language usually not, there you only have objects.

To make it simple, lets look at the java.util.Hashtable.

Suppose if you write this:

class MyClass {} the compiler would do this:
Object MyClass = new HashTable();

So, instead of defining a class, you just created an empty object ... I used a Hashtable, because that makes the later explanations more easy, it could have been simply an object of course.

So far your class has no properties ... no data and no methods.

So you likely would write something like this:
class MyClass {
Object start;
Obejct end;
}

As prototyped languages are usually typeless you would only need to write this:
class MyClass {
start;
end;
}

Our hypotetical compiler makes this from your typed code:
Object MyClass = new Hashtable(); // define a "new class"
MyClass.add("start", null);
MyClass.add("end", null);

So, instead of "defining" a class, like you did in Java or C++, you only created an object in the most global namespace. That object is called "MyClass" just as your class would have been called.

That object has two "slots" with the names "start" and "stop", just like a class would have two attributes of type Object.

So: the concept is called prototyping, because you would usually initialize the MyClass object more properly, so that "start" and "end" would have a value and would not be empty.

Now comes the interesting point: we know how to make classes now. How to make objects from them?

Well, all Objects have a method called "new".

In java you would write new MyClass(). But you could of course asume a class had a static method called NEW().

So MyClass.NEW() would create a new object of type MyClass. That method is usualy build into the language and every "class" has it. So, what does NEW() do? It "clones" the object MyClass.

In Java we have a class MyClass, and with new we create objects. The objects have some kind of poitner to their class.

In a prototyped language you only have objects. If you say new to them, they simply create a clone from themselves. The original object is called "prototype" or "traits". Instead of calling a constructor to initialize such a new created object it is fully initialized with default values during teh cloning.

Why did I use a Hashtable as example? Well, you simply can tell a Hashtable to clone itself ... if the Hashtable describes a prototype. The slots in a Hashtable are similar to teh slots in an object of an prototyped language. Suich a slot usualy has a name and can hold any object ... methods are objects as well :D

You can merge objects ... and so you do not only get a new object but also a new "class". Thats one way how inheritance could be implemented. But usualy you use nested Hashtables for inheritance, as yoou most often want single inheritance only .. and merging is used for mixins .... another term wixh would need an explanaition as long as this one.

Regards,
angel'o'sphere

Re:What I use to satisfy my needs...

[Deraj DeZine]

That link has an awful lot of plus signs. As if you're trying to hide something on the end of the URL. But what could it be? Maybe if I clic---No! Ow! My eyes!

I can't believe they changed the goatse.cx layout.

Eh

[Anonymous Coward]

Who gives a shit about the real world. None of the tools you cubicle-dwelling corporate serfs love so much ever came from the real world. All your programming tools come from research labs -- mere leftovers thrown away by academics once they grow bored of playing with them.

You code monkeys are nothing but low-skilled craftsmen, so when real scientists speak, please sit down and shut up, mkay?

April fools..I hope

[rufusdufus]

Confusing things like:

3 + 4 * 5 " ==> 35 (not 23) "

and

(3 / 4) == ( 3 / 4) "==> false"

give pause for concern.

But the example code snippet for the curious @ dispatch operator uncommented and unexplained takes the cake:

"
oc@(OrderedCollection traits) copyFrom: start to: end
[| newOC |
end start ifTrue: [^ oc newEmpty].
newOC: (oc traits newSize: end + 1 - start).
start to: end do: [| :index | newOC addLast: (oc at: index)].
newOC
].
"

How could someone argue with a straight face that this gobblygook is progress in programming languages?

Re:April fools..I hope

[Chinju]

I don't know much about Slate, or Smalltalk, or anything, for that matter, but a quick look at the article shows that both of your "confusing" examples are not that confusing...

As someone else already pointed out, "3 + 4 * 5" ==> 35 (not 23) because Slate has no differences in binary operator precedence and therefore always associates to the left.

And as for "(3/4) == (3/4)" ==> false, this is because "==" tests for _object_ equality, and the two different instances of "(3/4)", while representing the same numerical value, are distinct objects. It appears that "=" tests for numerical equality.

Re:April fools..I hope

[scrytch]

> 3 + 4 * 5 " ==> 35 (not 23) "

As it has always been in the smalltalk family of languages (which includes basically Smalltalk and Self). This was once considered a necessity as smalltalk was interpreted strictly as a stream of instructions (much like forth is now), but now that it's always compiled, I rather wonder whether this isn't legacy baggage. Certainly flexible overloadable operators aren't inimical to the notions of operator precedence, as the ML language family shows.

I certainly don't get why (3/4) != (3/4). If it's because it's inexact, they might learn a thing or two from how scheme handles it.

> [snipped example]
> How could someone argue with a straight face that this gobblygook is progress in programming languages?

Syntax-wise it sure isn't, it looks like slavish adherence to smalltalk's syntax, with Self's prototypes and C++'s klunky "traits" stapled on (traits are meaningless when you have either manifest types like scripting languages or type inference like ML). It's implemented in a language that itself manages to be a mismatch to Slate, but I imagine they want to make it self-hosting later on.

Slate has some really nifty ideas, but I've seen lots of nifty ideas come and go. Usually such projects run out of steam when they reach the final hump of getting everything integrated and performing well. Slate looks nice under the hood, even if it has an ugly paint job, but I damn near asphyxiated when I last held my breath on a similar project.

Re:April fools..I hope

[Decaff]

It would. A common mistake in Java is to try and compare Strings using == e.g.
if (a == "value")
instead of
if (a.equals("value"))

Wait a minute.......

[MasterSLATE]

Thats MY nick..... So, they're saying I'm a smalltalker with a lisp?

Shhhtop it! :(

Amazing.

[warrax_666]

And they say its syntax is easier to understand than LISP? I wonder what they're smoking...

prototype based languages

[Jecel Assumpcao Jr]

When running a program, it is very likely that you will want to create new objects as you go along. You have some alternatives:

• call a magic constructor fucntion (C++ and friends)
• send a message like "new" to a factory object (like a class in Smalltalk)
• send a message like "copy" or "clone" to an object that is like the one you want to create

In the third case you might find out that you can get by with a set of "prototype" objects to copy from and you don't need classes at all. But to actually eliminate classes you will have to find solutions to the other things they do for you like hold the behaviors for the objects (you can put them in the objects themselves, for example) and reflection (Self uses special "mirror objects" for that).

There are several different styles of prototype based languages.

Re:prototype based languages

[Piquan]

Being a Lisp programmer, I'm always looking for new ideas to bring into my Lisp programs. It looks like Lisp-- possibly even CLOS-- could support prototype-based programming without extensive pain.

One thing that I'm wondering about in prototype-based OOP is redefining stuff. In Smalltalk and CLOS (I don't know Self), you can redefine methods over classes on the fly, or change member variable definitions, or whatever. I take advantage of this to have a production server running for months while I make improvements.

But in a prototype language, this looks, well, difficult. If your methods are associated with prototype objects, then if you have existing non-prototype objects and change a method, then would the non-prototype objects get the method def passed down, or what?

It seems like a prototype language would also have problems with multiple inheritance and multiple dispatch, but it looks like they've licked those too. Interesting.

ain't nothin' wrong with prototype OO

[Laxitive]

Man, and here I am writing my own little VM for a prototype OO system.. seems to be all the rage nowadays :D. I'm liking the recent trends of languages evolving to use simpler and simpler higher level semantics. I am a fan of smalltalk and self, but not their syntax. Their language environment and semantics, though, are worth pursuing.

One of the reasons I like prototype OO (specifically, delegation-based prototype OO, as opposed to languages that use embedding), is that a lot of _other_ dynamic language models fit well on top of it. For example, it would be very simple to make a Python -> Self compiler, because constructs that self exposes can be used directly to implement more specific class-oriented pythonic constructs. It leads me to beleive that a prototype-oo oriented base-vm can serve as a good abstract platform environment for several dynamic 'scripting' languages.

I'm not sure about the multiple dispatch though. I think multi-dispatch can be confusing.. especially in languages like these where the notion of runtime types is muddled quite a bit of the time.

-Laxitive

I'm going to create the Stale programming language

[Anonymous Coward]

It's going to be based on COBOL, but will add the most annoying features of all of the other programming languges, and will leak memory like a firehose through a collander.

Objective C

[Doug Merritt]

Oh, I can't think of any other language that used smalltalk as a base... Oh yeah, except C++.

Objective C borrows both syntax and semantics from Smalltalk (on top of C itself, of course). It's a nice small language.

NewtonScript?

[Archibald Buttle]

Yet another language turns up that claims its virtual parents are SmallTalk, Lisp, and Self...

It would seem that Apple may have had it right ten years ago when they made NewtonScript, the native language of their Newton computers, since that language too claimed SmalllTalk, Lisp and Self as its antecedents.

Having had a brief look though at the documentation for Slate, and yesterdays Prothon, I can't help but feel that Apple did a much better job with NewtonScript and the Newton environment. NewtonScript seems to me to be much more mature and better thought out than these two examples.

As for comments that I read here about prototype-based languages not being suitable for application development and are effectively only the domain of accademics, I say bullshit. Class-based programming really isn't the only method of OO development, and prototypes can be equally effective. Many thousands of applications were written for the Newton, and they all used NewtonScript and its prototype-based object model. Prototypes can usually be used in a very similar way to classes, and most class-like behaviour can easily be simulated.

If you're interested in finding out more about how NewtonScript worked and functioned there reference manual can be found here:
http://www.unna.org/unna/development/docume ntation /NewtonScriptProgramLanguage.pdf
For a discussion of prototype vs. class based programming consult Appendix C of the NewtonScript reference manual.

A better smalltalk-like language

[cryptoluddite]

There are other Smalltalk-based languages that are far better than this, for example SmallScript. The guy behind it, David Simmons, is trying to learn from Smalltalk's mistakes:

• Isolated, all-in-one environment creates a with-us or against-us situation. Smallscript can plug into .NET, and you can embed C++ or other language code directly into the program and link to external code.
• Slow performance. Smallscript is targeted more at scripting, where performance is less critical. Even the best Smalltalks average about 1/10th the speed of C on common codes. All Smalltalks are significantly slower than Java.
• Complete lack of security. Smalltalks allow dynamically loading and running code (there are even smalltalk-lets like applets), but have no provisions for Java-like sandbox security. Smallscript has some provisions for security and can leverage .NET's security.
• Unnatural language syntax for programming. Smalltalkers claim their language is more like English, but most programmers just don't like it. Smallscript has added a few C-like keywords and syntax.
• Lack of solid, stable core. One of Java's strengths is a huge core library that is unmodifiable by applications. This means that everybody knows what the core does and what is available in it. Smalltalk core is flexibly, where developers add methods to objects on a whim and re-writing the actual code for the core objects. This means that apps are not portable to future language runtime versions and can't co-exist with other applications.

This new Slate language looks just like Smalltalk only with new features that nobody actually wants, such as prototypes instead of classes. AFAICT, it hasn't improved on any of the above problems and has actually made some of them worse. IOW, it's doomed.

Scallscript is a start. It's definitely the best of the breed. Personally, I think the greatest barrier to acceptance of Slate / Smalltalk / Smallscript / Squeak / Whatever is the language syntax. Programmers just don't yoda talking like, and a slightly-off Germanic style of grammar just doesn't fit well with an activity like programming that is more mathematical and logical than like communication.

Re:Pretty Cool

[be-fan]

Dylan is very not prototyped-based. Its class-based. Extremely cool language, though.

Dylan was hardly successful

[tommasz]

I remember Dylan, as a matter of fact I still have the book somewhere. It was another amalgam of programming language concepts that never went anywhere.

As elegant and admired as Lisp and Smalltalk are, they aren't exactly the most heavily used programming languages available (and I say that even though I love Smalltalk). Just because a language appeals to language designers, doesn't mean it's going to be embraced by the masses of programmers out there in the trenches. And the more of a mindshift necessary to use it, the less likely it will succeed.

People sometimes disparage C++, but it gained acceptance because C programmers could get their work done using it even if they weren't doing OOP programming. Evolution works where revolution fails.

Re:Dylan was hardly successful

[DrEasy]

True, but Smalltalk was about to hit the mainstream right when Java took off. I used to get spontaneous job offers around 98 just because of my Smalltalk skills. European banks in particular were replacing their old cobol code with Smalltalk, so there was money to be made there.

But Smalltalk couldn't rival Java in terms of marketing, and applets were supposedly the next big thing. If only ParkPlace had come up with a Smalltalk equivalent to applets...

Re:Dylan was hardly successful

[be-fan]

So what? At this point, I've given up ever hoping that the "programmers out ther ein the trenches" will ever wise up to the superior tools that are out there. There is no point in bringing those people into discussions about languages, because they'll never accept something unless its almost exactly the same as what they are already using. Witness C#, which is ever so slowly absorbing Lisp techniques. So far, it has GC, and in 2.0 will have lambda. In another decade, it'll get multimethods, another decade later it'll get macros. By about 2030, they will have matched Lisp circa 1980.

Re:Prototyping OO is not a great paradigm

[LittleDan]

What's wroing with prototype OO? You can use it in a completely class-based way if you wish. Prototyping only allows more flexibility. Many things in OO languages, such as Python exceptions, require a hierarchy of objects so they use classes. But this a hack; exceptions are objects, not classes. Although prototype-oriented languages haven't been used extensively in buisness contexts, neither have languages with type systems more advanced than Algol because the jump to a language that's not directly decendent from C is too great (unless it's from Microsoft, but for Microsoft they'd switch to assembly if it was marketed properly). Compared to FP, prototypes are almost completely unused in academia or any other sort of "ivory tower". What makes it difficult for inhreritance management? Daniel Ehrenberg

Re:Prototyping OO is not a great paradigm

[msobkow]

"Object and inheritance management" is only an issue for those who don't bother to analyze the problem and architect a solution. Slapping together code without understanding the problem is not "prototyping" -- it's wasting time.

Prototypes are for understanding the application requirements, not for "scripting." If you compare prototyping tools to production applications, you are completely and thoroughly missing the point for their existance.

In search of an appropriate unit of abstraction...

[alienmole]

There does seem to be a fair amount of interest in prototype-based languages lately. Javascript's object system is also prototype-based, also inspired in part by Self, as well as Lisp/Scheme. Javascript may have helped trigger the current wave of interest in this subject.

Purely prototype-based languages don't really compete with their more structured (class-based) cousins, though. One of the main benefits of prototype-based langauges is that they give a lightweight way to create an abstraction - you don't necessarily have to create a class first. This isn't necessarily a pure win. The structure provided by classes can be useful, too. A good language should provide both capabilities, no matter what mechanisms it uses to do that. It's possible Slate does this, I haven't looked.

Another good candidate mechanism for lightweight abstraction is first class anonymous functions, i.e. lambda, as found in Scheme, Lisp, Javascript, Perl (Python got it wrong, unfortunately). Having real lambdas tends to eliminate a lot of the problems which other languages find themselves trying to solve. Although it helps to also have macros, which limits the list to Scheme and Lisp.

Re:Dylan is technologically successful

[smittyoneeach]

If Microsoft had put its weight behind Dylan, instead of C#, then I think Java would have been in serious trouble.

Can we really make suck a strong claim about a language on its own?
These days, syntax and semantics are all fine and groovy. For any language, you expect variables and functions and such. One huge contributor to making or breaking a language in the marketplace, though, is its library support.
CPAN, the Python standard library, java.*, boost.org, .Net--all of these help their target language escape the ivory tower.

Corrections from one of the language authors

[water451]

This took me by surprise, and I'm not a usual poster here, so I don't have the energy to reply to each person in turn. So I'll summarize some points I've seen:

This post is entirely misleading; we are not researchers, and we do intend to do business based on this language. However, what the language itself is is entirely mis-represented. Note: the original submitter is not affiliated with our project in any way, and in fact does not actually know or use the language.

First, we are not in a project mode of self-promotion or public representation at all. Nothing on that site claims to be a real tutorial, and the current efforts have mostly been about experimentation. We are still preparing the really usable implementation, and have a huge set of ideas and environment enhancements in backlog waiting for this. What's mentioned on the front page is actually a mere fraction of what we're working on.

The project name, "Slate", is short for "Clean Slate Smalltalk". If you don't know Smalltalk, very little of it will make sense; what's at issue is that we mean what Alan Kay would say in that Smalltalk currently means Smalltalk-80, just a certain quirky snapshot of a whole range of ideas that he and others were working on. We're interested in that whole range.

Slate is only about prototypes insofar as this was an initial language stage that was simple to play with and powerful enough to explore without too many limitations. Further revisions of the language will feature higher-level facilities for more type-safe programming and more declarative consistency (declarative in the sense of (re-)defining a class and having its instances track that consistently).

Slate's environment is about 0.001% of completion of what we intend, and we have a huge body of experience and code and ideas to draw upon which are already largely mapped-out. What you see on the site is not representative of what we want in those terms.

The syntax is definitely odd. At issue is the fact that we kept a minimal Smalltalk syntax core and optimized it for "phrase value" and added various annotation mechanisms, which wind up being very hard to understand until you crack open the 40-page programmers' manual which explains this all. Although it is no tutorial, everything is explained there, and improved with feedback from early users.

Slate is eventually going to be a full environment, and be very flexible at a large scale, so that questions of prejudice about design choices will not matter, because we actively take part in designing the system so that users can make the choices: whether image-style live interaction or C-embeddable, highly-optimized, low-overhead, no-IDE deployment. And make it so you can make these choices independently; current Smalltalks, Lisps, Dylan, and hundreds of other languages (especially the more common ones) don't have this.

There are a number of issues brought up here which are addressed but not advertised on the front page; for example, Slate will handle security at the language level, using capability analysis and the subjective programming feature mentioned. Our project has no marketting team (see Smallscript), and has actively avoided public claims until we have the demonstration at-hand. I am giving a presentation and demonstration of the next major release, featuring a self-hosting (C-friendly) setup in Seattle at Smalltalk Solutions 2004 in May.

Inheritance in Prototype-based Languages

[ingenuus]

If your methods are associated with prototype objects, then if you have existing non-prototype objects and change a method, then would the non-prototype objects get the method def passed down, or what?

Your use of the term "(non)-prototype object" is a bit confusing since every object is a "prototype" which can be cloned... but I think I understand your question.

In prototype-based languages, creation of new objects occurs by copying (cloning) existing objects. After copying, the clone is independent from the original -- changing one has no effect on the other (there is no Inheritance relationship between them).

Inheritance-style call (message) dispatch is handled through a slot named "parent" that every Object has. A call (message) that does not have an object-local slot (handler) is deferred to the objects referenced in the parent slot. In this way, objects can share the same parent and thus the same behaviour (unless locally overridden).

Note that when a clone is made, all slots in the original are copied to the clone, so the clone has the same parents as the original. Of course, after cloning, you can change any of the clone's slots independently from the original, including the "parent" slot.

Prototype languages are really not much different from class-based languages... they just split up the responsibilities a bit differently (and perhaps more uniformily).

Re:Pretty Cool

[ron_ivi]

If I recall correctly, one of the guys behind Dylan ended up working on another MIT-based Lisp-Like language called Curl (more info at Curl Corporation).

It did a great job at bringing all the power of Lisp with all the symplicity of HTML. All the equivalents of HTML elements were just lisp-like function calls. Something like

(text this is (font color=red size=+2 big red text))

Since all markup was just a lisp-like function call like any other, extending the company to do more complicated things - like extending the HMTL-like-markup to do real time raytracing in the browser was really easy.

Unfortunatelly the company suffers from bizzare licensing policies and can't figure out if they're selling a language or products built on the language.

Most often used prototype based language is...

[jeti]

JavaScript

You read right. JavaScript has a prototype based system for objects. I seldom see this mentioned in language design discussions.
Actually I like JavaScript and it's prototype system quite a lot. It's a nice and powerful little language.
But that's likely only the case because I never needed to implement any cross-browser stuff in it.

RE: Theoretical computer scientists...

[Ignominious Cow Herd]

I wonder what Real computer scientists have been working on.

GNU Smalltalk

[hak1du]

If you are looking for a Smalltalk-like language for scripting applications without the Smalltalk GUI, check out GNU Smalltalk. It's a pretty faithful implementation of Smalltalk, and it even has a JIT.