[Interest] reading javascript body from c++

[Andy Mayer]

Am 10.12.2012 10:01, schrieb Thomas McGuire:
> Hi,
>
> On Saturday 08 December 2012 20:18:50 Andy Mayer wrote:
>> Am 08.12.2012 19:25, schrieb Thomas McGuire:
>>> On Saturday 08 December 2012 11:34:17 Andy Mayer wrote:
>>>> I have a question regarding the possibilty of reading the body of a
>>>> javascript function from c++. I want to create a DSL based on QML and I
>>>> have to read the body of a javascript function.
>>>>
>>>> e.g.
>>>>
>>>> QML:
>>>>     Item {
>>>>     
>>>>         function action() {
>>>>         
>>>>             console.log("Got message:", msg)
>>>>             return "some return value"
>>>>         
>>>>         }
>>>>     
>>>>     }
>>>>
>>>> C++:
>>>> QDeclarativeEngine engine;
>>>> QDeclarativeContext context(&engine);
>>>>
>>>> QDeclarativeComponent component(&engine,
>>>> QUrl::fromLocalFile("MyItem.qml")); QObject* qmlSpenat =
>>>> component.beginCreate(&context);
>>>>
>>>> QString actionString=qmlSpenat->property("action");//??? it doesn't
>>>> work, anything else?
>>> Should work with QMetaObject::invokeMethod().
>>>
>> Thanks for the answer, but I don't want to invoke the javascript method.
>> I want to read out the body of the javascript method from C++.
>>
>> e.g.: If I have a Javascript method within a qml-file
>>
>> function action() { var x=0; return x+2;}
>>
>> the question is: Is it possible to get the body "var x=0; return x+2;"
>> as QString (or something else?) from C++ side?
> Ah I see, that is quite an unusual usecase. Getting the function body as a
> string from the C++ side is not possible. However, the other way around is
> doable, you could pass the function body string from QML to C++, either with a
> function call or with a property binding.
> Something like
> 	myCppObj.passFunctionString(action.toString())
> Assuming that passFunctionString() is a C++ function that takes a QString as
> argument.
>
> Regards,
> Thomas
>
>
> _______________________________________________
> Interest mailing list
> Interest at qt-project.org
> http://lists.qt-project.org/mailman/listinfo/interest
ok I have it, thank you!

You are right, it is a quite unusual use case from 
implementation/runtime point of view. But I tried to use QML as a 
declaration mechanism for development of domain specific languages (see 
http://pvdev.wordpress.com/2012/06/04/custom-domain-specific-languages-with-qt-declarative-qml/).
I think it would be a very efficient approach. For the most use cases of 
DSL-developing QML has the right syntax and with the qtcreator-editor an 
outstanding editor with syntax highlighting and code completion. There 
is also a parser and after QDeclarativeComponent::beginCreate() an 
object-tree. A lot of work is already done.

But for my DSL (declaration of a special petri net) I need the body of 
the javascript functions. The workaround looks quite interesting...

Another question: Are there any plans to build a Xtext/Xtend-clone for Qt?

Thanks again and regards
Andy
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.qt-project.org/pipermail/interest/attachments/20121210/1175522e/attachment.html>