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Scala.js no longer experimental

scala-lang.org

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Re: Scala.js no longer experimental

#51

Post by switchbak »

jbooth wrote: post #49
noelwelsh wrote: post #26

I was very sceptical of Scala.js, but decided to use it in a low risk project ( http://github.com/underscoreio/doodle ) to render to the HTML canvas and I am shocked at how well it works. The community is moving very quickly as well, and many advanced Scala projects have had the necessary tweaks applied to run in Scala.js. Looking at broader trends, there is a clear movement towards static typing on the Javascript VM…

So here's my question, how come no browser has a way for a java applet to manipulate the DOM? We've got GWT compiling java to JS, we've got this compiling scala to JS.. and the JVM was originally built to run inside of a browser. Why can't we just close the circle? I guess people don't want their website visitors to see a "you must upgrade java" popup first thing?

There was - it was called LiveConnect - but like most things to do with Java and the browser(s), it languished in a half-supported state, and really isn't worth thinking about any more.

As are applets - a great idea, implemented poorly, and now essentially lost to the annals of history.

Re: Scala.js no longer experimental

#52

Post by _ea1k »

jbooth wrote: post #49
noelwelsh wrote: post #26

I was very sceptical of Scala.js, but decided to use it in a low risk project ( http://github.com/underscoreio/doodle ) to render to the HTML canvas and I am shocked at how well it works. The community is moving very quickly as well, and many advanced Scala projects have had the necessary tweaks applied to run in Scala.js. Looking at broader trends, there is a clear movement towards static typing on the Javascript VM…

So here's my question, how come no browser has a way for a java applet to manipulate the DOM? We've got GWT compiling java to JS, we've got this compiling scala to JS.. and the JVM was originally built to run inside of a browser. Why can't we just close the circle? I guess people don't want their website visitors to see a "you must upgrade java" popup first thing?

The old Netscape Java Applet APIs supported dom manipulation:

http://www.java2s.com/Code/JavaScript/Development/UsingJavaS...

I believe that other browsers that supported applets supported these APIs as well.

I don't think that anyone really wants to bring back Java Applets, though.

Re: Scala.js no longer experimental

#53

Post by egon_n »

julius wrote: post #35

This sounds great. I have not really used Scala before. 3 questions: - How good do IDEs understand Scala these days? Compared to C#/Java, where IDEs instantly know a crazy lot about your code. I am looking at features like IntelliSense, marking wrong code, marking typos, marking unused code, telling me about unhandled Exceptions etc. - Is there any difference, on the IDE side, between Scala support and Scala.JS suppo…

An additional answer to your bonus question is https://github.com/xored/scala-js-react

Which allows the following syntax: @scalax def render(self: This) = { Hello {self.props.name} }

Re: Scala.js no longer experimental

#54

Post by stingraycharles »

switchbak wrote: post #51
jbooth wrote: post #49

Earlier quoted context omitted.

So here's my question, how come no browser has a way for a java applet to manipulate the DOM? We've got GWT compiling java to JS, we've got this compiling scala to JS.. and the JVM was originally built to run inside of a browser. Why can't we just close the circle? I guess people don't want their website visitors to see a "you must upgrade java" popup first thing?

There was - it was called LiveConnect - but like most things to do with Java and the browser(s), it languished in a half-supported state, and really isn't worth thinking about any more. As are applets - a great idea, implemented poorly, and now essentially lost to the annals of history.

Don't forget about websites from academia that implement certain proof-of-concepts; for some reason that commumity still keeps using applets.

Re: Scala.js no longer experimental

#55

Post by _ea1k »

I understand why these types of compilers lack reflection support, but it still bothers me (and general makes me want to avoid them). JavaScript is naturally a very dynamic environment, and both Java and Scala have some pretty strong dynamic capabilities of their own.

But somehow when they are combined (GWT or Scala.js) you end up with something that is more static than Java or JavaScript. I know the reasons have to do with the static compilation optimization, but I still think this is a huge downside relative to languages that are designed for the browser from the start.

Re: Scala.js no longer experimental

#56

Post by apo »

Let's say I want to use Scala.js to build, not an application, but a JavaScript library. The library exposes a JavaScript API that JavaScript code can call. The library's objects can be used in full from JavaScript.

Can I do this with Scala.js? If so, how?

Very few, if no, *-to-JavaScript cross-compilers can do this. For example, Dart might seem to be that language, but on closer inspection, it's not. Your library is locked inside a JavaScript VM-like data structure.

Although you can get a JavaScript object out of Dart-to-JavaScript compiled library, you need to manually hook up every function in its API yourself. In other words, it's not practical to use Dart to build a JavaScript library that exposes a sophisticated JavaScript API.

Is this possible in Scala.js?

Re: Scala.js no longer experimental

#57

Post by txu »

desdiv wrote: post #36
noelwelsh wrote: post #26

I was very sceptical of Scala.js, but decided to use it in a low risk project ( http://github.com/underscoreio/doodle ) to render to the HTML canvas and I am shocked at how well it works. The community is moving very quickly as well, and many advanced Scala projects have had the necessary tweaks applied to run in Scala.js. Looking at broader trends, there is a clear movement towards static typing on the Javascript VM…

Google is developing SoundScript Aren't they doing Dart as well? That has optional typing. Plus they have GWT, which is Java to JS. Don't get me wrong, I'm super grateful to receive their fruits of labor for free, but this looks like a case of the left hand not knowing what the right hand is doing.

"Google’s product strategy: Make two of everything" http://arstechnica.com/business/2014/10/googles-product-stra...

Not a bad thing to let two or more projects compete to encourage innovation, than granting each team exclusive privilege to represent the whole company in the area.

Re: Scala.js no longer experimental

#58

Post by densh »

apo wrote: post #56

Let's say I want to use Scala.js to build, not an application, but a JavaScript library. The library exposes a JavaScript API that JavaScript code can call. The library's objects can be used in full from JavaScript. Can I do this with Scala.js? If so, how? Very few, if no, *-to-JavaScript cross-compilers can do this. For example, Dart might seem to be that language, but on closer inspection, it's not. Your library is…

Yes, this is possible.

http://www.scala-js.org/doc/export-to-javascript.html

Re: Scala.js no longer experimental

#59

Post by noelwelsh »

_ea1k wrote: post #55

I understand why these types of compilers lack reflection support, but it still bothers me (and general makes me want to avoid them). JavaScript is naturally a very dynamic environment, and both Java and Scala have some pretty strong dynamic capabilities of their own. But somehow when they are combined (GWT or Scala.js) you end up with something that is more static than Java or JavaScript. I know the reasons have to…

Reflection is very much the last option when using Scala, as it breaks the ability to statically reason about code.

Re: Scala.js no longer experimental

#60

Post by exprE »

stingraycharles wrote: post #54
switchbak wrote: post #51

Earlier quoted context omitted.

There was - it was called LiveConnect - but like most things to do with Java and the browser(s), it languished in a half-supported state, and really isn't worth thinking about any more. As are applets - a great idea, implemented poorly, and now essentially lost to the annals of history.

Don't forget about websites from academia that implement certain proof-of-concepts; for some reason that commumity still keeps using applets.

There are quite a few applets demonstrating chemical reactions/bonds or physical equations etc., and as such applets are relatively common in teaching materials for high school (/secondary education) physics and chemistry, at least with teachers (I had or) I have substituted.

They are obviously years old and rarely signed, which is a shame because quite often there are plenty of demos, none of which I can run with modern default settings of a PC (and sometimes I wouldn't have enough credentials to do anything about it, anyway).

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