I stopped reading the Haskell tutorial when I came to the part where arrays have to be homogeneous (or something like that, basically all elements in the array have to have the same type, if I remember correctly). That is one of the things that is most annoying in Java, so why put up with it in another language?

In a similar vein, I wonder about the Erlang hype - some things are really impractical to do in Erlang, for lack of syntactic sugar and the immutable memory constraint. People were always bickering about the constraints in Java (no multiple inheritance and stuff like that), so why choose another language with impractical constraints instead?

This is a little tricky, Types can be pretty broad. First, you could define a tree type with all sorts of different leaves, you could have a list of tree parts, something like:

Tree = Branch Tree Tree | ILeaf Int | SLeaf String

then a list like [ILeaf 1, SLeaf "foo"]. Another way to go takes advantage of type erasure. Currently it's just a popular extension but it lets you have lists of stuff in the same type class.

A good example is "Show" you can have a list off stuff that knows how to turn itself into strings. always a handy thing.

Basically you get the big two, group things based on what they are, or group things based on what you can do to them.

Perhaps there is a big pile of random stuff you want to hang on to, but i'd bet 99.9% of the time you really want to collect the stuff into a coherent type.

Some would call that a feature, not a bug.

There is a Lisp extension? library? that supports strong typing, it's called Qi: http://www.lambdassociates.org/

Lack of strong typing in a language is usually on purpose (dynamic typing). But sometimes you want it. I like the idea of optional strong typing in a language.

Perl6, may it rest in peace, had that feature in its spec.

Btw, will Arc ever be open-sourced?

I'd love to just sudo apt-get install arc in this lifetime.

For once, I will answer this question: yes, soon. This winter, I hope.

We are waiting to type:

  git clone git://ycombinator.com/arc.1.0.0

Nah. We're waiting to download the windows msi file, which optionally installs a Visual Studio integration doodad and an eclipse plugin.

At least, that's what the people who want to become lisp programmers want. It's probably not what the current lisp programmers want. Hey ho. Just don't make emacs the default development environment.

Emacs won't be default. pg uses vi. He highlights code segments and drags&drops them to repl.

Heh. Can't say that vi makes me feel much better ;)

Pg has a lot of people fired up about using lisps, but right now it's a sport you can only participate in if you've got a certain -other- set of skills like vi and emacs and a decent knowledge of system administration. Preconditions like this limit the user community massively. Small communities find it difficult to get momentum.

I've forced myself to stick with emacs/slime because basically that's that there is. I'm getting comfortable, and starting to like it. But I think it's actually a kind of Helsinki syndrome...

I'd like to write the next Viaweb, and I'd like to write it in Lisp. But if the basic language is inviting, the rest of the environment is sorta hostile; a shangri-la in a swamp.

So the quality of the installer, the libraries distributed with it, the documentation, and the bundled editor will ultimately affect it's success.

I am interested foremost in reading a description or specification of Arc, not using an implementation.

Just to continue this meme (YC's first?)...

I look forward to typing:

  emerge -av arc

I am waiting to type:

    darcs get http://ycombinator.com/arc

To complete the trinity: hg clone http://ycombinator.com/arc

I meant:

  git clone git://archub.com/arc.1.0.0

Very exciting.

Should we arrange another Lightweight Languages day at MIT for this?

More generally, somebody should arrange another Lightweight Languages day at MIT no matter what. Or maybe a Lightweight Languages days somewhere else. And wherever "they" organize it, it would be awesome if they could manage to webcast it and have people who cannot attend pose questions through IRC.

I attended Lightweight Languages once and it was awesome. Informal, a large variety of smart people, but each smart in their own way, that had a lot to genuinely learn from each other.

Sadly, conferences, even comparatively small and informal once, take some effort and some money to put together, and frankly it's not going to be me who is capable of coming up with either.

Will the source to news.yc also be released, as a non-trivial example program?

Do you know what kind of animal will be on the Oreilly cover?

Archaeopteryx - The First Bird

http://en.wikipedia.org/wiki/Archaeopteryx

It's not exactly a looker.

Still the very first bird, to which we owe Thanksgiving, Hot Wings and Avian Flu.

Fair enough. Credit where credit's due.

PG: Can an arc instance distribute its threads across multiple cpu's? I'm not asking "can-in-principle" but rather whether the current implementation has that feature.