JavaScript is the "VM" to target for D

[Eric Poggel]

On 4/20/2010 8:50 AM, Justin Johansson wrote:
> A new moon (downunder) brings time for new D discussion topic :-)
>
> Myself having a long time interest in "webapp" development and given
> that the web client platform is tied to having only JavaScript
> ubiquitously available (i.e. in the browser) and having tried a zillion
> OOP wrappers and frameworks for JavaScript that don't scale for
> significantly-sized apps,
>
> my current thinking seems to be aligning with others that JavaScript
> should be seen as the new "binary", albeit in text form, that HLLs
> should be compiling down to for "webapp" development.
>
> Accordingly I would like to promote a discussion on the suitability of
> D, perhaps even D1, as a HLL that could possibly compile down to
> JavaScript as a better candidate language compared to some of the other
> contenders.
>
> To set some context for this discussion consider that GWT (Google Web
> Toolkit) is basically Java transmutated into JavaScript "object code"
> which is ultimately deployed on the client though development is
> facilitated via a Java IDE.
>
> Also there is Haxe, http://haxe.org/ , which reminds me of D1, it being
> small and concise, and, well, rather than my words, let me copy what the
> intro page says:
>
> haXe (pronounced as hex) is an open source programming language.
>
> While most other languages are bound to their own platform (Java to the
> JVM, C# to .Net, ActionScript to the Flash Player), haXe is a
> multiplatform language.
>
> It means that you can use haXe to target the following platforms :
>
> * Javascript : You can compile a haXe program to a single .js file. You
> can access the typed browser DOM APIs with autocompletion support, and
> all the dependencies are resolved at compilation time.
> * Flash : You can compile a haXe program to a .swf file. haXe can
> compile for Flash Players 6 to 10, with either "old" Flash<8 API or
> newest AS3/Flash9+ API. haXe offers very good performance and language
> features to develop Flash content.
> * NekoVM : You can compile a haXe program to NekoVM bytecode. This can
> be used for server-side programming such as dynamic webpages (using
> mod_neko for Apache) and also for commandline or desktop applications,
> since the NekoVM can be embedded and extended with some other DLL.
> * PHP : You can compile a haXe program to .php files. This enable you to
> use a high level strictly-typed language such as haXe while keeping full
> compatibility with your existing server platform and libraries.
> * C++ : You can now generate C++ code from your haXe source code, with
> the required Makefiles. This is very useful for creating native
> applications, for instance in iPhone development.
>
> The idea behind haXe is to let the developer choose the best platform to
> do a given job. In general, this is not easy to do because every new
> platform comes with its own programming language. What haXe provides to
> you is :
>
> * a standardized language with many good features
> * a standard library (including Date, Xml, Math...) that works the same
> on all platforms
> * platform-specific libraries : the full APIs for a given platform are
> accessible from haXe
>
>
> So I guess the thrust of my topic tonight is, could D somehow reinvent
> itself to fame and fortune in the high-level-language-for-JavaScript space?
>
> Cheers and beers as usual,
>
> Justin Johansson

I've done a significant amount of web-app development myself, but to me 
this seems like a bad idea.  If I want to sit down and write something 
quickly and don't care about performance, JavaScript or Haxe are great 
languages to do it in and can be more productive than D.  However, even 
the best JavaScript vm's (like V8) are on average 10x slower than C++/D. 
  So if performance matters, I always chose D.

If I write D to run on a JavaScript VM, I lose both the productivity of 
JavaScript and the speed of D.