As I’ve covered in several blog posts, I visited the Emerging Languages camp last week. It was an interesting experience for many reasons, and some of my conclusions are still half formed. I wanted to talk a little bit about some common themes in several languages presented at this camp, and also what the trends are leaning towards. Now, I’m not entirely sure what my insights will be yet, but hopefully I’ll know as I approach the end of this blog post.

There are several different axises you can divide the presented - about 26 - languages. The first one is in terms of age and maturity. The oldest language presented was probably Parrot, Frink, Io, Factor and D - who have all been around for eight to ten years. All of these languages are very mature and you wouldn’t hesitate to use them for real life work. The second category are the languages that range from a few years in age to quite new ones. Most of these languages are still evolving, still not stable, but definitely on the path to getting there. The final set of languages are the most interesting in my view - the new ideas that have just started germinating, or even concepts that aren’t actually there yet. From my list of interesting things, Wheeler is definitely a language in that category.

But you can also look at the types and features you find in the new languages (and I will exclude the oldest group of languages when talking about these features and ideas). There is a large group of languages that are evolutionary rather than revolutionary. This is fine, of course. Many of these languages take much inspiration from Ruby and Smalltalk. Object orientation is extremely common among these languages, several of them prototype based. There was also several languages with indentation based syntax. I was surprised about the amount of languages that target native instead of a virtual machine. AmbientTalk, Clojure, Ioke/Seph, Frink and Mirah targets the JVM, Stratified JavaScript, E/Caja and CoffeeScript targets JavaScript and F# targets the CLR. All the other languages can be considered native. I was quite surprised about this - anyone got a good explanation?

There are also several graphical languages presented. These are harder to categorize from a traditional paradigm perspective. Thyrd is more of a proof of concept, very graphical, but backed by a stack language in the style of Forth. Kodu seems to have a quite traditional backend, but the graphical interface hides that in most cases. Both of these languages are optimized to run in situations where you don’t always have a keyboard - Thyrd for tablet PCs and Kodu for the XBox. Subtext/Coherence is based around non-syntactic thinking, but didn’t seem to have a graphical interface either at this point.

As mentioned above, the trend of using JavaScript as a target language also seems to be on the way up - both CoffeeScript, Caja, and Stratified JavaScript follows that approach. Parts of Ur/Web are also compiled to JavaScript to allow the based language to describe behavior in both the server and the client. Gilad reported that he was very interested in getting Newspeak to run on JavaScript too, and there has been a lot of talk about getting Io to work on that platform too. This seems to be an interesting idea for many languages, and the benefits of compiling to a language that can run in any browser is definitely compelling. However, there seems to be a lot of problems with that approach too. Some people create a bytecode machine in JavaScript that then executes generated bytecodes. Some languages have to do lifting of functions because of bugs in several JavaScript implementations. And of course, the JavaScript language doesn’t give you good ways of generating code that is easy to debug.

The low level languages all seem to give interesting capabilities. D is what C++ should have been. BitC allow you to write programs with strong guarantees. ooc gives many of the high level benefits to a low level language. Go makes it possible to handle concurrency in an easy and powerful way.

I’m at the end of my thoughts right now, and there is no grand conclusion to be found. Just some interesting observations. Maybe they are indicative of the future in language development, and maybe not.

2 Comments | In: blogging | tags: emerging languages, programming language design, programming languages. | #

I’ve been dropping a few hints and mentions the last few weeks, and I thought it was about time that I took some time to preannounce a new project I’m working on. It’s going to be much easier writing my next few blog posts if people already know about the project, and my reasons for keeping quiet about it have mostly disappeared. It’s also a moot point since I talked about it at the Emerging Languages camp last week, and the video will be up fairly soon. And I already put the slides online for it, so some things you might have already seen.

So without further ado, the big announcement is that I’m working on a new language called Seph. Big whoop.

Why?

I already have Ioke and JRuby to care for, so it’s a very valid question to ask why I would want to take on another language project - outside my day job of course. The answer is a bit complicated. I always knew and communicated clearly that Ioke was an experiment in all senses of the word. This means my hope was that some of the quirky features of Ioke would influence other languages. But the other side of it is that if Ioke seems good enough as an idea, there might be value in expanding and refining the concept to make something that can be used in the real world. And that is what Seph is really about. That blog post I wrote a few weeks ago with the Ioke retrospective - that was really a partial design document for Seph.

So the purpose of Seph is to take Ioke into the real world while retaining enough of what made Ioke a very nice language to work with. Of course, being the person I am, I can’t actually avoid doing some new experimentation in Seph, but they will be mostly a bit safer than the ones in Ioke, and some of the craziest Ioke features have been scaled back a bit.

Some features

So what’s the difference? Seph will still be prototype based object oriented, in the same way as Ioke. It will definitely consider the JVM its home. It will be homoiconic, and allow AST manipulation as a first class concept - including working with message chains as a way of replacing blocks. It will still have a numerical tower. It will use almost exactly the same syntax as Ioke. It will still allow you to customize operators and precedence rules.

The big difference. The one that basically makes most all other design changes design themselves is a small but very important difference: objects are immutable. The only way you can create new objects is by creating a new object that specifies the difference. This can be done either by creating a new child of the existing object, or creating a new sibling with the specified attributes changed. In most cases, the difference between the strategies isn’t actually visible, so it might be an implementation strategy.

Now once you have immutable objects but still focus on polymorphic dispatch, that changes quite a lot of things. It changes the core data structures, it changes the way macros work, it changes the flow of data in general. It also changes what kinds of optimizations will be possible.

Another side effect of immutability is that is becomes much more important to have a good module story. Seph will have first class modules that ends up still being simple Seph objects at the same time. It’s really a quite beautiful and simple scheme, and it makes total sense.

If you’re creating a new Object Oriented language, it turns out that proper tail calls is a good idea if you can do it (refer to Steele for more arguments). Seph will include proper TCO for all Seph code and all participating Java code - which means you’ll only really grow the stack when passing Java boundaries. This will currently be done with trampolining, but I deem the cost worth the benefit of a tail recursive programming style.

I mentioned above that objects are immutable. However, local variables will be mutable. It will also be possible to create lexical closures. I’m still undecided whether it’s a good idea to leave a big mutable hole in the tyoe system, or whether I should make it impossible for lexical closures to mutate their captured environment. Time will tell what I decide.

Stealing is good

Seph believes in reusing concepts other people have already made a great job with. As such, many pieces of the language implementation will be stolen from other places.

Just like in Ioke, the core numbers will come from gnu.math. This library has served me well, and I’ll definitely continue to use it. The big difference compared to Ioke is that the gnu.math values will be first class Seph object, and won’t have to be wrapped. Seph will also have real floats instead of bigdecimals. This is a concession to reality (which I don’t much like, btw).

Seph will incorporate Erlang style light weight threads with an implementation based on Kilim (just like Erjang).

As mentioned above, the core data structures will have to change. And the direction of change will be towards Clojure. Specifically, Seph will steal/has stolen Clojures persistent data structures, all the concurrency primitives and the STM. I don’t see any reason to not incorporate fantastic prior art into Seph.

As mentioned above, the module system is also not new - it’s in fact heavily inspired of Newspeak. Having no globals force this kind of thinking, but I can’t say I would have been clever enough to think of it without Gilad’s writings, though.

Basically everything else is copied from or inspired by Ioke.

Isn’t mutability the essence of Ioke?

If you have worked with Ioke, or even heard me talk about it, you might have gotten the impression that mutability is one of the core tenets of Ioke. And your impression would be correct. It wasn’t until I started thinking about what a functional object hybrid version of Ioke would look like, that I realized most of things I like in Ioke could be preserved without mutability. Most of the macros, the core evaluation model and many other pieces will be extremely similar to Ioke. And this is a good thing. I think Ioke has real benefits in terms of both power and readability - something that is not easy to combine. I want Seph to bring the same advantages.

Will you abandon Ioke now?

In one word: no. Ioke is still an experiment and there are still many things that I want to explore with Ioke. Seph will not fill the same niche, it won’t be possible for me to do the same experimentation, and fundamentally they are still quite different languages. In fact, you should expect an Ioke release hopefully within a few weeks.

So will it be useful?

Yes. That’s the whole goal. Seph will have an explicit focus on two areas that Ioke totally ignored. These areas are concurrency and performance. As seen from the features above, Seph will include several powerful concurrency features. And from a performance standpoint, Ioke was a tarpit - even if you wanted to make it run faster, there wasn’t really anything to get a handle on. Seph will be much easier to optimize, it’s got a structure that lends itself better to compilation and I expect it to be possible to get it to real world language performance. My current idea is that I should be able to get it to JRuby performance for roughly the same operations - but that might be a bit optimistic. I think it’s in the right ballpark though. Which means you should be able to use it to implement programs that actually do useful things in the Real World ™.

Is it available?

No. At the current point, Seph is still so young I’m going through lots of rewrites. I would like the core to settle down a little bit before exposing everything. (Don’t worry, everything is done in git, and the history will be available, so anyone who wants to see all my gory mistakes will have no trouble doing that). But in a nutshell, this is why this is a preannouncement. I want to get the implementation to the stage where it has some of the interesting features I’ve been talking about before making it public and releasing a first version.

Don’t worry though, it should be public quite soon. And if I’m right and this is a great language to work in - then how big of a deal is another month of waiting?

I’m very excited about this, and I hope you will be too! This is an adventure.

13 Comments | In: ioke, seph | tags: concurrency, ioke, programming language design, programming languages, seph. | #

The second day of Emerging Languages camp was at least as good as the first day. We also managed to squeeze in four more talks, since everybode agreed that the afternoon pause was too long and ineffective during day one. At the end of the day my brain was substantially melted that I didn’t even contemplate finishing these comments. But after some sleep I think I have a fresh perspective.

The sessions were a bit more varied compared to the first day - both in quality and how far out the ideas were. Because of how my interest in various subject vary, there might be some inconsistency in length of reporting on the different languages.

Anyway, here goes:

Kodu

Kodu is a language from Microsoft for creating games. It’s specifically aimed at kids to see if they can learn programming in a better way using something like this. The language uses icons and a backend text based syntax to make it easy for someone to program using structure instead of syntax. You get a basic 3d environment where you can modify and edit things in various ways. Another important part of the design is to get the game to quickly do something, so you get immediate feedback. Everything added to the language is user tested before adding it - including doing gender testing. They thought long and hard about whether they should add conjunctions or not - but ended up deciding for doing it. You work with an XBox when programming and running the game. It’s also free. Overall, Kodu looks like a really nice and innovative initiative, probably going back as far as Logo in terms of inspiration. Very nice.

Clojure

Rich didn’t actually talk much about Clojure in general, but decided to focus on a specific problem he is working on solving. His talk title doesn’t really say much about this, though: “Persistent, Transience, Persistents, Transients and Pods - invasion of the value snatchers”. It was a great talk with lots of information coming extremely fast. I found myself focusing more during this talk than during any other during the conference, just to follow all threads of thought.

Rich spent some time giving an introduction to persistent data structures so everyone knew how Clojure works with them - including how they are turned into transients - since that’s where the new feature comes in.

An important part of persistent data structures is that yu preserve the performance guarantees of a mutable equivalent of that data structure. Clojure uses bit-partitioned hash tries, originally described by Phil Bagwell. This allows Clojure to have structural sharing, which means it’s safe to “update” something - the old version is retained. It uses path copying to make it possible to udpate with a low cost. There is definitely cost to doing it, but it works well in a concurrent environment where other solutions would be more costly to get correct results.

Clojure has an epochal time model that allows Clojure to view things as values inbetween being “modified”. State is at one step higher than that, so you can see mutable change as a creation of a new value from an existing value that is then put into the same reference the original value existed in. Clojure has four different types of references with various semantics for coordination.

To get good performance, some Clojure functions will actually mutate state that is invisible to anyone else to efficiently create new data structures. To get performance that is acceptable to Rich Clojure, data structures are not implemented using purely immutable data structures (Okasaki style) from the Java side. Persistent data structures also doesn’t scale to larger changes, specifically multiple collections, several steps or other situations where you want to have functional end points but efficient mutation inbetween.

Transients is a feature that allows Clojure to give birth to a data structure. Clojures transients will accumulate changes in a safe way and can then finally give you a persistent value. Only vectors and hash-maps are currently supported. Lists are not, since there is no benefit in doing that. Transients also enforce thread isolation. Composite operations are OK, and so is multi-collection work and you don’t need any locks for this. This is already in Clojure, but they might be doing too much. They both handle editing and enforce the constraints on it, such as single-threadedness. Transients can sometimes return new values too, even on mutating operations.

Pods allow you to split out the policy from transients. Values go in, values go out. The process goes through the pod. Different policies are possible, such as single-threadness or mutexes. A pod knows how to make a transient version of a value. Functions to modify a pod will have to return a new thing (or the same thing). Dereferencing the pod allows you to get a new value from a pod at that point. This gives you the possbility to apply recipes on ordinary Java objects too. A good example is String vs StringBuilder. Pods can ensure lock acquisition order, but not lock composition - although pods can detect it at least. There are still a few details in the design that Rich hasn’t decided on yet.

All in all, a very interesting talk, about the kind of concurrency problems you wish your language had.

E/Caja

Mark Miller recapped the interaction models of the Web, starting with static frames going to the current mess of JavaScript fragments going back and forth, using JSONP, AJAX and Comet. He also talks a bit about  the adoption curves of languages and why some languages get adopted. Posits that a mess of features may be easier to get adopted. This means many languages succeed by adding complexity.

E is an experiment in expressing actors in a persistent way. He used some of the lessons from E combined with AJAX/JavaScript to create Caja, a secure language. Some of the features from Caja were then used  to start work on EcmaScript 5. They are currently working on a standard for SES, secure JavaScript. Dr. SES is an extension of this, that stands for Distributed, Resilient, Secure JavaScript. Object capabilities involve two additions to a regular memory safety and encapsulation model; effects only on held references, and no powerful references by default. This means a reference graph becomes an access graph. Caja can sanitize JavaScript to prevent malicious behavior, but preserve the semantic meaning of the program outside of that.

He showed some examples of how Caja can be used to sanitize regular JavaScript and have it running securely. Very interesting stuff, although the generated code didn’t look as amenable to debugging as something like CoffeeScript.

Fancy

Fancy is a language that tries to be friendly to newcomers, with good documentation, a clean implementation and so on. It’s inspired b several languages: Smalltalk (pure message passing, everything’s an object, dynamic, class based OO, metaprogramming, reflective),  Ruby (file based, embraces UNIX, literal syntax, class definition is executable script, fixed some inconsistencies with procs/lambdas/blocks), Erlang (message passing concurrency, light weight processes - not implemented yet). Fancy takes the opinion that first class is good; classes, methods, documentation, tests should all be first class. FancySpec is a simple version of RSpec. Tests for all built in classes and methods are there. These tests are not dependent on implementation. There are plans to port Fancy to a VM. Methods marked with NATIVE will have an equivalent method in Fancy and in the interpreter, to improve performance.

It’s got dynamic scoping and method caching. Logic can be defined based on the sender of a message, which makes it possible to do things like private and public.

Exceptions are taken directly from the implementation (ie C++).

The language seems to be pretty similar to Ruby in semantics, but more Smalltalk like syntax.

BitC

BitC is geared towards critical systems code. Resource contrained, CPU, memory, those kind of areas. One cache miss sometimes counts. Abstraction is fine, but only if it’s the right one. Variance constrained too. Predictability is very important, so something like a JIT can be a problem. Statically exception free. “Zero” runtime footprint. Non-actuarial risk model. Mean time between failures in decades. Problem is to establish confidence. After other failures in this area, the conclusion has been that BitC shouldn’t be a prover.

The language is an imperative functional language with HM-style parametric type system. You have explicit control of representation. State is handled in a first class manner. Inferencing actually infers mutability in lots of cases. Dependent range checking isn’t there yet, but is coming soon. “The power of ML/Haskell”, “The low-level expressiveness of C”, “Near-zero innovation”.

Trylon

Trylon is a small language, indentionation based and compiles through C. It’s object oriented, with prototypes under the class based system. According to the author, nothing really new in the language - he just did it for his own sake. There are no users so far except for the author.

ooc

The language tries to be a high level low level language. It mixes paradigms quite substantially and has some nice features. It’s class based, and mostly statically typed.

Coherence/Subtext

Jonathan Edwards started this presentation by showing a small example where the ordering of statements in an implementation is dependent on what representation you use for data, and shows that it’s impossible to handle this case in a general way. From that point he claims that there is a fundamental tension between styles in a language, and you can only get two of these three: Declarative programming, Mutable state and Data Structures. I’m not sure if I agree with his conclusions, and the initial example didn’t feel like anything I’ve ever had trouble with.

Based on the conclusion that you can only have two of the three, he goes on to claim that the thing that cases all these problems is aliasing. So in order to avoid aliasing, his system uses objects where instances are physically always contained within another object. This means you can refer to these objects without having actual pointers - and thus cannot do aliasing either. From that point on, his system allows declarative programming of the flow, where updates never oscillate back out to create more updates.

Lots of interesting ideas in this talk, but I’m not sure I agree with either the premise or the conclusions.

Finch

Finch is a small programming language, bytecode compiled with fibers, blocks, TCO, objects, prototypes, a REPL and Smalltalk style message selectors. In the feature, the author aims to add metaprogramming, some self-hosting, continuations and concurrency features.

Circa

Circa is a small programming language that allows you to get immediate feedback. It’s aimed at game programming, and achieves this by running the script many times (one time for every frame as far as I understood it). You then specify what state you have in your program, and this state will be automatically persisted between invocations, so that a specific invocation of a specific function will always get access to the same state it started out with. This was a very interesting but weird model. It seems to work really well for smaller prototyping of games and graphics but I’m wondering what can be done to expand it.

Wheeler

Wheeler is a proof of concept presented by Matt Youell. It’s pretty hard to describe, and I’m not even sure if there’s a computational model there yet. The project is apparently just a few weeks old, and the ideas are still in progress. The basic tenets of the language seems to be that you work with categories of things and establish transitions between them. A transition pattern matches things that it looks for, which means that things like syntax and ordering doesn’t mean as much. The author calls it mutual dispatch, because it uses the types/categories of everything involved to establish what transitions to use. At this point there is no time model, so everything happens in one sweep, but once a time model gets in there it might be very interesting. To me it looked a bit like a cross between neural networks and cellullar automata.

Interval arithmetic

Alan (Mr Frink) gave a talk about the problems with floating point numbers, and one way of handling that. Floating point numbers cause problems by making it possible to introduce small errors.

Intervals is a new kind of number. It represents a specific number by giving two end points and saying the real number is somewhere within that interval. You can see it in two different ways: “the right value’s in there somewhere but I’m not sure where” or “the variable takes on ALL values in the interval simultaneously”.

This was a very interesting discussion, and you can find out more about it from Frink’s web page (just search for Frink and interval arithmetic). At the end of the presentation, Alan gave this challenge to other languages:

for:

x=77617

y=33096

calculate:

((333 + 3/4) - x^2) y^6 + x^2 (11x^2 y^2 - 121 y^4 - 2) + (5 + 1/2) y^8 + x/(2y)

Ioke handles it correctly, both using ratios and using decimals.

Stratified Javascript

Stratified JavaScript adds some concurrency features to JavaScript based on Strata. It looked like a very principled approach to giving JS concurrency primitives that are easy to use at the same time as they are very powerful. The presenter showed several examples of communication, blocking and coordination working really well.

Factor

Factor is a very high level stack based language created by Slava Pestov. He went through some of the things that Factor does well and other dynamic programming languages handle less well, like reloading code from the REPL. Lots of other small tidbits of how powerful Factor is and how expressive a stack language can be. At the end of the day I still think it’s interesting how much Ioke code sometimes resemble Factor, even though the underlying semantics are vastly different.

D

Walter Bright showed D, his systems level programming language. He focused on showing that it can do several different paradigms in the same language - all of it looked very, very clean, but I got the impression that D is an extremely big language from these examples. To summarize, D can do inline assembler, class based OO, generative programming, RAII, procedural, functional and concurrent programming (and I probably missed a few). I liked the approach to immutability, but I must admit I’m scared of the sheer size of the language. It’s impressive how such a big language can get so good at compile times.

AmbientTalk

AmbientTalk is a language built on top of Java that puts communication in center. It is supposed to be used in areas where you have bad network connectivity and want to communicate inbetween different devices in a flexible way. Things like network outages aren’t exceptions because they will happen all the time in the environments AmbientTalk is built on. The language embraces futures to a large degree and also takes a principled approach to how Java integration works - so that if you send an AmbientTalk object in to Java, it will work as if you had sent it to a remote device, and the only way Java can interact with that object is by sending messages to it. Much interesting stuff in this talk.

And that was it. I can obviously not capture all the interesting hall way and pub conversations that were had, but hopefully this summary will be helpful until the videos come along in two to four weeks. I would call this conference a total success and I really look forward to next year.

8 Comments | In: blogging | tags: clojure, conferences, emerging languages, programming language, programming language design, programming languages. | #

Yesterday was the first day of the Emerging Languages Camp, a part of OSCON specifically organized for language creators and designers. You can read more about it at www.emerginglangs.com. The first day was fantastic, lots of very interesting talks and great conversations. The amount of brain power in this room is really humbling.

The format of the camp is that there are about 20 speakers and each speaker gets 20 minutes. This is a fairly limiting format and means the speakers will have to focus their talks quite substantially. I expected a few talks (including my own) to bomb completely because of this, but it didn’t happen during the whole day. All of the talks were very different but good in many ways.

All of the presentations are filmed by Confreaks and will be available within a few weeks.

I’ll try to write a few sentences about each presentation, with thoughts and impressions baked in.

Go

Rob Pike started out the day by talking about the history of CSP (communicating sequential processes) and the lineage of languages that led to Go. Most of the talk was based on using channels/goroutines to handle concurrency. It was definitely a good talk, but it didn’t get me more interested in using Go for anything.

Ioke/Seph

I had the second slot. I had twenty minutes to cover both Ioke and a new language I’m working on, called Seph. Against all odds, my talk went quite well and I managed to communicate the things I wanted to get said. Hopefully the audience wasn’t too bored.

Thyrd

Thyrd is a proof of concept visual language, focused on using tablets for programming - so it’s distinctly none-textual. In many cases you drag and drop operations instead of typing them. The actual development happens in a recursive grid of cells. I’m wondering what the audience for this language would be - it definitely looks intruiging though, and I like how some algorithms ended up being very easily readable and understandable.

Parrot

Allison Randall gave a talk about what’s currently happening with Parrot. It seems they are going for a new rewrite of most of the subsystems. One of the changes is going from a CISC style op code system to a RISC style. Parrot apparently has over 1200 op codes at this point, and they want to scale back everything to about 20-30 bytecodes instead. As a preparation for this, they have ripped out the JIT and will revisit most of the subsystems in Parrot to see what can be done. Allison also gave the audience the distinct impression that Parrot is still quite slow for user programs.

Ur

Of all the talks during the day, I think I understood the least of the Ur/Web talk. Ur is a functional limited programming language focused specifically on building web applications. It’s got dependent types inspired by Agda and allow you to statically check your whole program. The example shown was a simple CRUD app, and I didn’t get any impression of how complicated it would be to actually use it for a real world application. The speaker said the only real world web app he knows about is a hosting application for Ur applications that he is building himself.

Frink

I don’t think I can do this presentation justice. Frink is just incredibly cool and you should check it out. It’s a general purpose programming language, but it’s got units of measure and several other features builtin that makes it very easy to use it to calculate all kinds of interesting facts. As an example, he showed that if all people in China jumped at the same time, that would be equivalent to 4.7 on the Richter scale.

Newspeak

Gilad Bracha talked a bit about the basic ideas and principles behind Newspeak and what the current status is. Gilad focused on no global state, and all names being late bound (including class names). The first feature falls quite naturally out of prototype based OO, so it’s something both Io, Ioke and Seph has (and it’s really nice). The second feature is a bit more obscure, but I’m not sure if it gives as many benefits as the first one.

F#

Joe Pamer talked about what they had to do to take F# from a research language to something Microsoft could ship in Visual Studio 2010. Not something most of us really think about, but there are lots of challenges in doing that kind of transition. Joe covered this quite well and also gave us an insight into the current state of F#.

CoffeeScript

CoffeeScript is a language that compiles down to JavaScript. In comparison with GWT for example, it’s pretty close in semantics to JavaScript, and the generated code can be debugged and looked out without wanting to stab out your eyes. The syntax of CoffeeScript is very pleasant and looks very nice to work with (it’s indentation based, and focuses on getting lambdas to be as small as possible). Next time I’m reaching for JavaScript, I think I might just go for CoffeeScript instead. Good stuff.

Mirah

Charles Nutter covered Mirah (the language formerly known as Duby). It looks more and more complete and useful, and sooner or later I’m going to try switching most of my Java development to Mirah. The extensability features makes it possible to do metaprogramming tricks in Mirah that you wouldn’t even try in Ruby.

Io

Steve jumped in last minute to cover for the Objective-J guy who couldn’t be here. Steve covered the basics of Io, talking about concurrency and the other basic features.

It’s been a great first day, and now day two begins - so I’ll have to focus on that.

10 Comments | In: blogging, ioke | tags: conferences, emerging languages, ioke, programming language, programming language design, programming languages, seph. | #

It’s been a bit over 18 months since I first released Ioke in the wild. During this time I’ve always been specific about Ioke first and foremost being a language experiment. I changed many things to see what would work and what would not. I thought I’d take stock and take a look at a few of these decisions and how I feel about them now. Ioke never got a huge user base, of course, so most of these impressions are based on my continued working on the language, and also experiences trying to explain features of the language.

This does not mean in any way that the Ioke experiment is over. I will continue working on Ioke and see what else interesting will come out of it.

White space separation for method calls

I adapted Io’s, Self’s and Smalltalk’s syntax for Ioke. This meant I could use periods to end expressions instead (taking the role of semicolons in most other languages). Personally I like this a lot. Readability really improves substantially by using white space for method calls. The only thing that makes it a bit tricky is the interaction regular expression syntax. I ended up adding an initial character to regular expressions to make them easily distinguishable. I thought I would dislike that more than I do. So white space is definitely a win.

Keyword syntax in method calls

Having methods take keyword arguments and positional arguments baked in to the language was also a big win. It’s really a huge difference between this approach and something like Ruby - having it first class means it is easy to do things like collecting all keyword arguments, provide default values and so on. It also makes introspection and documentation much better. Finally, the duality if dictionary creation with keywords and regular method invocation ended up being very pleasing. Another clear win. Languages should have keyword arguments.

Nontraditional naming

I wanted to see what would happen if I stayed away from the traditional names in the object oriented languages of today. So I didn’t use Object, String, prototype, slot, clone or property. The most obvious place for this is in the core concepts of the language. The place where user code starts is called Origin. I’m don’t miss Object as such, but I’m not sure Origin is the clearest way of talking about this object. My current thoughts are going in the direction of something like “Vanilla” (from Flavors), or “Something”.  Another problematic renaming was to talk about the act of creating a new object as “mimicking”, and call the parents of an object “mimics”. It ended up being very confusing, both from a verb/noun standpoint, but also just from simply being to opaque. So that’s a definite failure. I’m still comfortable with “cell” instead of “slot” or “property”. I’m also happy with “Ground”, “Base” and “DefaultBehavior”. All of these communicate clearly what they should. I’m also happy about the renaming of “String” to “Text”. I don’t use the type name much in Ioke code, but when I do “Text” feels much better.

Numerical tower, and no real numbers

I’ve always liked numerical towers in programming languages, and it feels good to have it in Ioke. Ratios are also necessary as first class concepts. I also decided to not have real numbers, only the equivalent of BigDecimals. That was probably a good decision for Ioke, and I still feel real numbers are problematic. I don’t think removing them from the language is the right solution though.

Condition system instead of exceptions

The decision to adapt and include a condition system based on Common Lisp was definitely a success. I like the programming model and it makes code much more flexible and expressive. Clear win.

No global scope

This is also a clear win. It’s a tricky one in many languages do. You have to unify things to a high level to make it possible to get away from global state. But I think the benefits way outweigh the cost of this.

Specialized forms of code

Ioke have quite a few variations in runnable code. The main distinction is between things that are lexically scoped and things that are object scoped. Methods, Macros and Syntax are object scoped, while Blocks and Lecros are lexically scoped. This seemed like a good idea at the time, but if I were to do it again, I would try to unify several of those - at the cost of making the evaluation rules slightly more complicated. Especially having methods that aren’t lexical closures still surprises me regularily. I wonder if I was influenced by the way Ruby works when designing these parts.

Prototype OO

I’ve always maintained that properly implemented propotype based object orientation is both conceptually simpler and more powerful than class based object orientation. I still believe this to be true, and I still think prototype based is better than class based. However, there are some places where the model breaks down. There are some situations where it just makes sense to have a class that describes objects. Take numbers for example. In a prototype based scheme, what is the parent of the number 2? Is the parent the number 1? Not really. In Ioke I added a singleton object Number that is the parent of all numbers. But that still becomes weird since you could write code like “Number + 9″, and expect that to work. I’m not sure how to solve this problem. Of course, prototypes can represent classes without problem, but my problem is mostly what makes sense intuitively.

Ruby-like load/require system

For a language with a global scope and/or total mutability, it works quite well to just have things represented as scripts that will modify a shared environment when loaded. However, there are things that become cumbersome - parameterization of modules/files become very ad hoc, and there is a real risk of conflicting names. If I were to redo this part I would probably opt for something slightly less convenient but more powerful, that allow you to work with software modules in a better way. Exporting parts and keeping other parts private, parameterize modules, bind modules under different names, and so on.

4 Comments | In: ioke | tags: experiment, ioke, language, programming language, results. | #

This saturday, May 1st, I will be talking at both the Chicago Code Camp and the Iowa Code Camp. I will be giving an introduction to Ioke at both code camps, and I will actually have slightly more time than I usually do - so hopefully this introduction will be the best intro to Ioke ever. I’ve also hacked on some fun stuff for Ioke lately that hopefully will be done by Saturday, so I might show some of that.

Hope to see many of you there!

2 Comments | In: ioke | tags: chicago code camp, code camp, ioke, iowa code camp, presentations. | #

I will speak at ÜberConf in Denver in June. Should be lots of fun! I will talk about JRuby and building languages. I might also possibly cover Ioke - we’ll see what happens.

No Comments | In: blogging | tags: conferences, jruby, uberconf. | #

A few months back I added support for destructuring assignment and tuples to Ioke. Since Ioke’s assignment is just a regular method call, this was actually fairly easy to do. The end result is that you can do things like (x, y) = (13, 14). You can also do more interesting things, such as ((x, y), (x2, y2)) = [[1,2],[3,4]]. Notice that the right hand side is not a tuple anymore, but a list. Anything that can be turned into a tuple using the asTuple method can be on the right hand side, or an item in a recursive destructuring.

All this functionality makes code slightly more readable. But last week I decided to add support for eachCons and eachSlice, and suddenly I realized that destructuring would be very nice to have not only in the explicit assignment case, but also in cases where you want to pick apart the arguments to an enumerable or sequence method. So I added those, which means that suddenly lots of code becomes much more simple.

Short story, in all Sequence and Enumerable methods, at every place where you could put an argument name, you can now put a destructuring statement instead. Let’s take a look at an example:

Point = Origin with(asTuple: method((x, y, z)))

points = [
  Point with(x: 42, y: 14, z: -1),
  Point with(x: 20, y: 0, z: 444),
  Point with(x: 31, y: 646, z: 3),
  Point with(x: 456, y: 14, z: 12)
  ]

distances1 = points consed map(obj,
  ((obj[0] x) * (obj[1] x) +
    (obj[0] y) * (obj[1] y) +
    (obj[0] z) * (obj[1] z)) sqrt)

distances2 = points consed map(
  ((x1,y1,z1), (x2,y2,z2)),
  (x1*x2 + y1*y2 + z1*z2) sqrt)

distances1 inspect println
distances2 inspect println

This code first creates a Point that can be coerced into a tuple of x, y and z coordinates. We then create a list of Points with different coordinates. We then want to calculate the three distances between the four points. We do this in two ways, using the old method and then using destructuring. The method consed is a sequence version of eachCons. The default cons length is 2, so this will yield three entries with two points in each. We then call map on the sequence. We will get a List of two entries, where each entry is a point. Finally we use Pythagoras to calculate the distance.

The second version is very similar - the only difference is that instead of using the square brackets to index into the lists, we instead give a pattern. This pattern contains two patterns, and the variable names inside of it will be bound to the right parts of each point.

At least in my mind, the destructured syntax is much more readable than the original one. And remember, this works for anything that can be turned into a tuple, which means you can use it on any Enumerable - you can use it on a Pair (such as what a Dict will yield) or any thing you would want to add asTuple to on your own.

1 Comment | In: ioke | tags: destructuring, ioke, programming language design. | #

I am very happy to announce that Ioke P has finally been released!

Ioke is a language that is designed to be as expressive as possible. It is a dynamic language targeted at the Java Virtual Machine. There also exists a version for the CLR. It’s been designed from scratch to be a highly flexible general purpose language. It is a prototype-based programming language that is inspired by Io, Smalltalk, Lisp and Ruby.

Homepage: http://ioke.org
Download: http://ioke.org/download.html
Programming guide: http://ioke.org/wiki/index.php/Guide
Wiki: http://ioke.org/wiki

The two specific releases that encompass Ioke P are ikj 0.4.0 and ikc 0.4.0.

Ioke P is the fourth release of Ioke. It includes many new features compared to Ioke E:

• Number Infinity
• eval
• Reflector
• Hooks
• First class Runtime
• New parser
• Tuples
• Structs
• Destructuring assignment
• Message rewriting
• Functional composition
• Sequences
• Dictionary and Set versions of Enumerable methods
• Enumerable group, Enumerable groupBy
• Set operations for union, intersection, membership, subset and superset testing
• ISpec stubbing and mocking
• IIk history
• DokGen on separate projects

Ioke P also includes a large amount of bug fixes.

Features:

• Expressiveness first
• Strong, dynamic typing
• Prototype based object orientation
• Homoiconic language
• Simple syntax
• Powerful macro facilities
• Condition system
• Aspects
• Java integration
• Developed using TDD
• Documentation system that combines documentation with specs
• Runs on both the JVM and the CLR

The many things added in Ioke P could not have been done without the support of all the Ioke contributors. Thank you!

Regards
Ola Bini    - ola.bini@gmail.com

4 Comments | In: ioke | tags: ikc, ikj, ioke, ioke P, release. | #

One of the problems you might encounter using a native Emacs on top of Mac OS X is that your custom PATH variable doesn’t really translate into your running Emacs instance. This might show up as making it impossible to run things like Ruby or Ioke from inside of Emacs - complaining that it can’t find the executable in question.

Another thing you might notice is that your Ruby environment is messed up - all the gems you so carefully installed isn’t around, and overall things just seem weird. One thing that could cause this is when you have a custom built Ruby installation in for example /opt/local or /usr/local instead of /usr. But Emacs just seems to pick up the original versino that shipped with OS X.

The reason for all these weird behaviors is that if Emacs is started from the Dock, or using the application directly, it doesn’t actually pick up the carefully prepared PATH variable you have in your terminal. Instead it will go ahead and use the default system PATH, which is very restrictive.

The way I prefer to solve this is to make sure that OS X plist version of the PATH variable is the same as my terminal one. I do that by resetting this plist on every login. Of course, OS X will not actually reload this without a reboot. If you just want to fix this once - and you’re reasonably sure you won’t change the path again, you can execute this command from the terminal and restart. Everything should be fine after that. The magic incantation looks like this:

defaults write $HOME/.MacOSX/environment PATH “$PATH”

(Note, I’ve had to solve this problem twice, since the first time I encountered it I didn’t blog about it. So now I’m blogging so it might also stick in my long term memory. Maybe it’s enough if it’s in my blog term memory…)

8 Comments | In: Uncategorized | | #