Thanks Stephen!
I found a solution, which is very similar to your approach.
QJSValue myExt = m_engine->newQObject(new ScriptModuleMath());
// mount the whole class ScriptModule to the engine --> Math.sqrt(4)
m_engine->globalObject().setProperty("Math", myExt);
// mount only the sqrt function to the engine --> sqrt(4)
m_engine->globalObject().setProperty("sqrt", myExt.property("sqrt"));
the first mount allows me now to access the whole object and of course my
sqrt() method.
i.e. Math.sqrt(4);
the second mount allows me to directly access the sqrt() method without the
instance.
i.e. sqrt(4);
Thanks for your suggestion.
Best Regards,
Stefan
-----Original Message-----
From: Interest [mailto:interest-bounces+stefan.walter=lisec....@qt-project.org]
On Behalf Of Stephen Bryant
Sent: Dienstag, 23. Februar 2016 15:12
To: interest@qt-project.org
Subject: Re: [Interest] QJSEngine replacement for QScriptEngine misses
newFunction
Hi Stefan,
On Tuesday 23 February 2016 05:34:03 Walter Stefan wrote:
[...]
>
> And in this way. I can use it then in the script:
> value = sqrt(4);
>
> I actually don't want to map a whole QObject, because that would
> require a call like this: value = MyMath.sqrt(4);
>
> Is there any way to achive in QJSEngine the same result as I do within
> the QScriptEngine?
Is far as I know, the only way is to do the thing you don't want to: map the
whole QObject. You can, however, add a JS function reference inside the engine
so you can call the function without the object name.
QJSEngine engine;
engine.globalObject().setProperty(
"MyMath",
engine.newQObject( new ScriptModuleMath( &engine ) ) ); engine.evaluate( "var
sqrt=MyMath.sqrt;" ); // repeat for other functions
This will now work in JS: value = sqrt(4);
You'll presumably be aware that all public slots of MyMath will automatically
be available as JS functions. That makes things a little easier.
It seems that you also need a QObject instance, event if you only want to
expose static methods.
BTW: your C++ native function can use this signature: double sqrt(double);
You'll get NaN if somebody calls it with a non-number. The return value is
also automatically converted as there is a QJSValue constructor that takes a
double.
There's no direct equivalent of read-only/undeletable, unfortunately. I'm
missing that too. The closest you can get is that your MyMath functions can't
be altered from JS, and you can also make a read-only Q_PROPERTY.
However, there is nothing stopping somebody from reassigning properties of the
global object - so your 'sqrt' function and 'MyMath' object could be replaced.
This may be a security concern, depending on what you're doing.
Best regards,
Steve
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