So like Google's Go is from Mars: A first glance

Well, I heard about the new language Go this afternoon, and it sucked a bit of time that I'm really short on. First note is that Go is from Mars. Take this sample from the tutorial:

for i := 0; i < flag.NArg(); i++ {
    if i > 0 {
        s += Space
    }
    s += flag.Arg(i);
}

Personally, I've never seen curly-based syntax without parens on fors and ifs. Just doesn't seem right to me. There's some other style in the language that's new to me. It looks so strange that I'd almost think it were an April Fools joke ... if it were April 1st, I guess.

But to get past the initial shock of alien appearance, here's my take at a first glance. This is based on their docs. I haven't actually tried it out.

The good:

• Pure interface, simple struct, no-inheritance, straight functions OO. If you've read other posts on my blog, you can imagine I'd love this. I'm glad someone was brave enough to try it out.


• Super fast compiler. C and C++ stink in this arena.


• Fast execution, supposedly near native.


• Lightweight threads and message passing, a la Erlang. Scalability should be sweet.


• Normal goodies like closures and type inference.


• Opinionated in some things: UTF-8 source, public/private by naming convention (caps for public).


• Fairly simple namespacing.


• BSD licensing.


• It's from Google. Google has $$$$$$. They can push things forward.

The bad:

• The syntax. It's just grating to me at this point.


• Too much focus on ad hoc solutions rather than general principles.


• No concept for nullable pointers vs. not.


• No operator overloading.


• No easy interfacing to C++.


• Is it cross-platform (meaning at least Windows, Mac, and Linux) yet? I'm not sure.

The ugly:

• Um, no exception handling. Seriously. So, um, expect to have to manually check for errors all the time. Which means, expect average programmers to ignore lots of errors and write buggy code.


• Well, I'd complain about this if there were exceptions, but there's no mechanism for automatic resource cleanup (beyond garbage collection) that I could find. Less need without exceptions, but it still seems like a glaring hole to me. Also, if the closures and
  anonymous functions are good enough, maybe I'm also overstating this one.

Probably forgetting something.

Between the ugly and the fact that they aren't really production-ready yet, I think I'll just keep a watch on it for now. What I really want is language that IDE-friendly and human-friendly, compiles and runs like lightning (including fast starts and low memory usage), and instantly consumes C and C++ libraries. Oh, and doesn't make it painfully easy to ignore errors.

GPGPU in the browser

This winning entry in the Mozilla Labs Jetpack competition might get many of the details wrong (as examples, why part of Jetpack instead of as its own extension and how it uses Nvidia CUDA instead of a cross-vendor solution), but I'm still super excited that it has drawn attention to putting GPGPU in the browser. So, three cheers for Alexander Miltsev!

Inverse Programming Assignments

I was just wondering today if there was a good way to let students play the part of the computer instead of the programmer. That is, they would be given a program and be required to push and pop off the stack, change variable values, allocate objects on the heap, deal with arrays, handle conditionals and loops, choose which line to execute next, and so on.

It might be possible on paper, in board game format, or maybe more reasonable as a video game of sorts. Increasing levels of complexity (introducing new language features and machine concepts) might be nice.

Just wondering if playing the computer would help some folks with understanding the system better.

Liberally licensed embeddable web server for C or C++?

I've done some searching in the past but couldn't find a liberally licensed embeddable web server for C or C++. That surprised me. I'm so used to having multiple good options in Java (such as Jetty) or built-in web servers say in Fan or Ruby.

Two options I've looked at are libmicrohttpd (but it's LGPL which causes too much bother) and lighttpd (but it's not really designed to have an embedded option so far as I can tell, which rather surprises me). Anything else out there?

Member access syntax: dots, brackets, and functions

I've spent some time thinking about common alternative syntaxes for accessing object members. By members, I mean methods or fields or whatever. For example, we have the struct dot syntax:

person.age
array.length

And so on. C++ extended C to use the same syntax for method calls:

person.age() or person.getAge()
array.length()
pen.moveTo(x, y)

Languages like Eiffel, Ruby, or Fan that treat all method calls as abstract messages don't distinguish between field access and method calls.

Anyway, then we have array or hashtable access syntax, a different kind of membership:

persons[4]
properties["background"]

And languages like JavaScript unify the two; properties.background and properties["background"] mean the same thing. There's some nicety to that.

But I'm working through a series of issues that will eventually get tangled. First, I need to go back to C. I can abstract member access there, too:

age(person)
length(array)
moveTo(pen, x, y)

I'll pretend to have those namespaced for the moment (since otherwise in C they'd have uglier names), and if I have dynamic dispatch on the first (or more) arguments, this syntax could have the same meaning as virtual methods in C++ or Java or whatnot. For example, MATLAB can do OOP method dispatch with standard function call syntax.

So the syntax question becomes do you like nested function calls or postfix member dot access? I think the postfix (or somewhat infix) C++ style is easier to understand:

toUpper(firstName(person)) vs.
person.firstName.toUpper

The chain is just easier to read. And apparently the C# folks thought so enough that they introduced extension methods. A semi-complicated way of allowing dot chain syntax. Why not just make a language such that both syntaxes are equivalent?

One reservation. Here's that tangle to which I was referring. Lets look at arrays again. Why do we really need a separate array access syntax vs. function call syntax? An array is just a function that hardcodes the responses, in one way of looking at it. So, like Scala or MATLAB, we could make them the same:

persons(4) vs.
persons[4]

And that frees up brackets for other uses (like generics in Scala). But, if like JavaScript, we consider struct membership and array-ish access to be the same, then 'persons[4]' is the same as 'persons.4', and that would be the same as '4(persons)', and all the worse if it's the same as 'persons(4)'.

So, it tells member that array/hashtable lookup should best be separate syntax from function calls. I like it ('persons[4]') as shorthand for notions like 'persons.get(4)'. I think otherwise the unification of concepts leads to entanglement.

At least, I haven't worked out another solution I like better.

Teaching Ideas: Quick Syllabus

I've been thinking about teaching ideas. I'm still rather sold on the weekly, multiple choice, open book quiz thing.

I think I've also decided that the syllabus should fit in one page. I'd love to get to real content even the first lecture. And the first quiz should include questions about the syllabus.

Unrelated question: Could it possibly be easier to introduce Python and then teach Java in one semester than just to jump directly into Java? Maybe for some people. Not sure I'd be that brave (or be able to get approval) to try it out, though.

I do hope to get the chance to teach soon.

Tamarin Nanojit

I sometimes get a hankerin' for programming languages. And I love script-style execution and high speed. I also love fast start-up and low memory consumption. Both of those points are making me more and more shy of the JVM.

So, how do you get your hands on a well-maintained cross-platform JIT? Maybe Nanojit (used by Tamarin and therefore Flash; also used by Firefox 3.5's TraceMonkey) is a good choice. Looks small and fast. Maybe even tasty. Something to keep in mind perhaps.

Tamarin also includes a garbage collector, as a related morsel. Here's hoping it's all thread-safe.

Again, just notes for the future.