D to Javascript converter (a hacked up dmd)

[Jacob Carlborg]

On 2012-03-01 19:56, Alex Rønne Petersen wrote:
> On 01-03-2012 19:04, Ary Manzana wrote:
>> 3. With JS you don't have to compile and run your code (well, I guess
>> you could make something smart in D for that).
>
> ? The D -> JS converter just translates it. It's no different from
> running e.g. the CoffeeScript compiler.

It's quite a difference. The semantics of CoffeeScript and JavaScript is 
more alike than D and JavaScript. CoffeeScript was created to be compile 
to JavaScript, not something you could say about D.

>> 4. If you write JS you can debug it in the browser. No need to track
>> back to the original source code.
>
> Valid argument. Maybe we can make the D -> JS converter help in some way
> here?

Similar problem with CoffeeScript, not as bad as with D since it outputs 
readable JavaScript.

>> 5. If you don't like JS syntax or verbosity, you can use CoffeeScript,
>> which is just a syntax rewriter, not a language/paradigm shift:
>> http://coffeescript.org/
>
> Don't even get me started on the horrible "features" in CoffeeScript.
> The guy who wrote the language literally had no clue what he was doing
> (he admitted to reading some "make your own language" book), and it
> isn't much better than JavaScript in terms of odd behavior and weird
> design decisions.

It's way way WAY more better than JavaScript.

* Class based object model
* Function binding, language support for binding the this reference

If CoffeeScript had only these two features it would be so much more 
useful than JavaScript, but it has a lot more:

* Extremely short function/lambda syntax
* Built-in loop comprehension
* == behaves as you would expect
* Existential operator
* Default arguments
* Variadic arguments
* Object syntax
* foreach loop that actually makes sense
* Almost everything is an expression
* No need to declare variables
* Implicit returns
* No need for semicolons (yeah, I know JS have this as well but most 
don't seem to use this feature)
* Ranges
* Arrays slicing

>> 6. Javascript objects have some built-in properties that are different
>> from D. So implementing those in D would make their performance worse
>> (but you can always hard-code those functions into the compiler and
>> translate them directly to their JS equivalent).
>
> Can you be a little more specific here?
>
>>
>> The good thing about writing in D is that you could probably get some
>> IDE for autocompletion and such. You might also like to type things
>> instead of using dynamic types.
>
> To be fair, excellent JS IDEs exist already; Visual Studio has great JS
> auto-completion, and ReSharper enhances it a lot too.
>


-- 
/Jacob Carlborg