Hacker News Reader

Comment by cpr | Hacker News Reader

Given my Java hatred (perhaps irrational), and no real allegiance to iOS & Cocoa Touch (other than it works very well, and has paid off somewhat for our efforts), I wonder if it would make sense, long-term, to mount an OSS effort to build a truly wonderful dynamic language environment as an alternative to Dalvik?

E.g., something based on Javascript, with a fully dynamic remote IDE/editor (along the lines of SLIME)?

I guess then you'd run into the problem that the whole Dalvik UI scheme is so heavily intertwined with their Java-based toolkit (just as iOS is heavily dependent on Obj-C) that there's no real gain in the end?

(Don't everyone hate me at once. ;-)

View on HN

Why not build a great dynamic language on top of Dalvik? All the alternate language projects for Android that I'm aware of are either native code (that uses JNI to talk to the UI code in Dalvik) or are existing JVM languages that are poorly matched to the Dalvik VM.

Dalvik isn't a Java JVM, it doesn't use Java bytecode and it has a significantly different architecture than JVM's. It's possible you might be able to make a language that's a better fit for Dalvik than Java is.

One possible candidate - Qt Lighthouse Android port: http://code.google.com/p/android-lighthouse/ Hypothetically Qt could be a robust cross-platform solution for mobile phones just like it is on desktop. But mobile platforms are more closed. And Qt is owned by Nokia now which brings in a lot of politics in the game. The good news is that the Qt team has seemingly been very enthusiastic about the Qt Lighthouse project so far.

"OSS effort to build a truly wonderful dynamic language environment as an alternative to Dalvik?"

You could save yourself quite a lot of time and start with Squeak or Pharo. MIT license, VM built for the dynamic, good tools, and no real reason you couldn't put another language on top of it.

If your talking building a language/IDE to compile to Dalvik (seems the next paragraph leans that way), then I think you really need to get a feel for how dynamic the Dalvik VM is and what you need in a language to call the shipping runtime.

SL4A (formerly known as ASE)[1] and Groovy both come to mind, although a 30 second Google couldn't find me a good resource on how/whether you can use Groovy to build Android apps.

I know SL4A has some GUI support, but I don't think it's as rich as the full Android UI framework. However, it seems like it could be a good base to build a UI layer on top of.

[1]http://code.google.com/p/android-scripting/

Why not use HTML5+JavaScript? Remote IDE here: http://www.cloud9ide.com/

I wish somebody had already recreated the native widgets of Android/iOS in HTML.

At least on iOS, recreating the "feel" of the scroll views is actually impossible with reasonable performance (the CSS 2d transitions don't have the correct interpolation options), so you can't make anything, at least there, that "feels" native.

So the browser doesn't scroll natively? Don't know the iOs scroll views... Still, an approximation would be nice, it doesn't have to mimic every teeny detail.

It does, but you can't scroll part of the page in the native way -- iOS users are very accustomed to the kinetic scrolling, anything even slightly different is enough to throw them off and make your app seem "weird".

"E.g., something based on Javascript, with a fully dynamic remote IDE/editor (along the lines of SLIME)?"

What about WebOS? It will get you at least halfway there. Unfortunately, it doesn't have the reach that Android or iOS have. It's still fun to play with, though.

Remember, you can also use any language that compiles to Java bytecode on a JVM. A short list includes Scala, Clojure, Ruby, Python, Groovy and even Javascript(via Rhino). So the JVM and Java are very much separate things.

Unfortunately, the Dalvik VM and JVM are quite different too. Dalvik may act like a JVM and talk like a JVM but it isn't a JVM (not according to Google, at least; Oracle thinks otherwise).

Reply on news.ycombinator.com