dmd support for IDEs

[Jacob Carlborg]

On 10/11/09 20:58, Yigal Chripun wrote:
> On 11/10/2009 15:23, Ary Borenszweig wrote:
>> Walter Bright wrote:
>>> In my discussions with companies about adopting D, the major barrier
>>> that comes up over and over isn't Tango vs Phobos, dmd being GPL,
>>> debugger support, libraries, bugs, etc., although those are important.
>>>
>>> It's the IDE.
>>>
>>> So, while I'm not going to be writing an IDE, I figure that dmd can
>>> help. dmd already puts out .doc and .di files. How about putting out
>>> an xml file giving all the information needed for an IDE to implement
>>> autocompletion? There'd be one .xml file generated per .d source file.
>>>
>>> What do you think?
>>
>> What I think is that even with an xml representing the parse tree (maybe
>> with some semantic stuff resolved) it'll be still incomplete for a real
>> IDE (the kind of thing users expect from an IDE). You can see this
>> video, for example:
>>
>> http://www.youtube.com/watch?v=KQbTT605ags
>>
>> So you have:
>>
>> ---
>> module one;
>>
>> class Foo(T) {
>> static if (is(T == class)) {
>> T property;
>> } else {
>> T someMethod() { return T.init; }
>> }
>> mixin(guessWhat!(T)());
>> }
>> ---
>>
>> You want to define an xml for that module that'll help IDEs. Can you
>> think what it'll look like?
>>
>> Now the user writes in another module:
>>
>> class Bar {
>> }
>>
>> void x() {
>> auto foo = new Foo!(Bar)();
>> foo. <-- what does the IDE do here?
>> }
>>
>> Now, the correct thing for the IDE to do is to suggest the field "Bar
>> property". How can the IDE do that just with an xml? It can't. It need
>> to perform some kind of semantic anlysis to Foo's argument to see if
>> it's a class, match the static if in the template, replace template
>> parameters, etc. It also needs to evaluate the string mixin.
>>
>> Of course you could say "Bah, just show all the declarations inside the
>> template in the autocomplete", but that's wrong. That'll lead to files
>> that don't compile. You could ommit supporting autocompletion or other
>> nice features, but that's exactly the big features of D. If you don't
>> support that then it's like using Java or C# from within the IDE: you
>> could use the advanced features but the IDE won't help you. And in your
>> discussions with companies adopting D, I'm sure they were talking about
>> great IDEs like JDT Eclipse or Visual Studio, not just some tool that
>> helps you a little but not anymore when things get interesting.
>>
>> Oh, and you need to have some kind of semantic analysis to know the type
>> of "auto foo". Again, maybe the IDE can be dummy and see "auto foo = new
>> Foo!(Bar)" and say "ok, foo's type is Foo!(Bar)", but then you have:
>>
>> auto b = foo.property;
>> b. <-- and here?
>> // remember "property" is templated and depends on static analysis
>> // or the IDE could need to resolve alias this or other things
>>
>> So... my opinion (like some others, I see) is to either ask things to
>> the compiler directly (but here the compiler lacks some info, like exact
>> source range positions), or to have a compiler (not a full-blown one,
>> just the front-end) built into the IDE, and that's what Descent is.
>> Unfortunately Descent is sometimes slow, sometimes buggy, but that's
>> normal: just a few people develop and maintain it (so I can see a
>> similarity with dmd here, where each day I see two or three new bugs
>> reported). If more people were into it, more unit tests were written
>> into it and, most of all, more people would use it, it'll get better.
>>
>> Another problem that people see in Descent (maybe also JDT Eclipse and
>> Visual Studio0 is that it's huge, it consumes a lot of memory and they
>> don't want to open a huge tool just to hack some lines. My answer is:
>> memory performance can be improved (but not a lot), but since an IDE is
>> a huge tool it requires a lof from the computer. And an IDE is not meant
>> to be used to hack some lines, it's meant to help you write big project,
>> huge projects without getting lost in the amount of code.
>>
>> So my bet would be to start supporting an existing IDE that integrates a
>> compiler into it. Updating it is easy: just port the diffs between DMD
>> versions. It's a huge job for one or two people, but if a lot of people
>> were involved it's not that much. Of course I'd recommend you to try
>> Descent since I'm one of it's creators and I do believe it can get
>> pretty good. :-)
>
> well put.
>
> btw, given that we have a port of SWT for D, how hard would it be to
> create our own native D version of eclipse?

Frank Benoit (who started DWT, the tango version) was think about this. 
Quite a big part is already ported, SWT, JFace, Forms, OSGI and so on, 
see: http://hg.dsource.org/projects/dwt2/file/88652073d1c2/ .

I think one of the biggest challenge to port is class loading, dynamic 
libraries could work for this but we all know how well they work on windows.