Script - writeConfig with QVariant

[Matěj Laitl]

On 13. 3. 2013 El boulangero wrote:
> Hello everyone,

Hi!

> I writing a scritp for Amarok at the moment, and I have a question
> regarding the Amarok.Script API.
> 
> I understand perfectly the config function with string argument, ie:
>    - String readConfig( String name, String defaultValue )
>    - void writeConfig( String name, String content )
> 
> But I'm curious about the two other ones, with QVariant argument:
>    - QVariant readConfig( String name, QVariant defaultValue )
>    - void writeConfig( String name, QVariant content )
> 
> At first, I thought that with these functions, I could put my script config
> in a JSON object, and save it in one call.
> 
> For example:
> > var defconfig = {
> >     "time": {
> >         "monday": {
> >             "enabled": "true",
> >             "value": "08:00:00"
> >         }
> >     }
> > };
> > 
> > Amarok.Script.writeConfig("", defconfig);
> 
> But if I try that, I get the following error:
> > Script error reported by: Good Morning TypeError: ambiguous call of
> > overloaded function writeConfig(); candidates were
> > writeConfig(QString,QVariant) writeConfig(QString,QString)
> 
> Is there something else I should do in order to use these functions? Or
> maybe I'm completely wrong, these functions are not suppose to be used with
> JSON objects?

First, bad news: QtScript bindings of Amarok are in rather unmaintained state. 
:-(

Good news: you can fix them! :-)

To answer your question: Your code is much probably right, but the Amarok part 
may have never worked, you've just first to shout loudly. To quote from [1]:
> Like other C++ methods, meta-methods can be overloaded, and they can have
> default arguments. The QtScript binding tries to ensure that the intended
> overload is called. First, if there is an overload that expects precisely
> as many arguments as were passed, that overload is selected. Second, if
> there's more than one such overload, the decision is based on a heuristic
> of how well the source (JS) argument types match with the target (C++)
> argument types. If the heuristic doesn't help either, a TypeError is
> thrown.

The error you have seems to happen in the Javascript wrapper of 
AmarokScriptConfig class. What I suggest is that you rename QVariant variant of 
the writeConfig in src/scriptengine/AmarokScriptConfig.{h,cpp} method and see if 
it fixes your problem.

You might encounter another problem that KConfigGroup::writeEntry( QString, 
QVariant ) doesn't support complex QVariants (those with containers in them), 
please consult its documentation and implementation.

[1] http://trac.webkit.org/wiki/QtScript (probably best C++ <-> QtScript 
interaction documentation, better than official Qt doc)

Regards,
		Matěj