QScriptEnging::evaluate() returning value

0...-5

Morning!
I noticed the following trouble using Qt scripts: when I call QScriptEngine::evaluate("1 + 2") I get a number (isNumber() == true) as expected, but calling QScriptEngine::evaluate("return 3") returns unknown QScriptValue that cannot be converted to a number. Can I use return-operand in my script code or not?

tucnak

bq. QScriptEngine::evaluate(“return 3”)

Have you ever seen script, with body:
@
return 3;
@

Try to evaluate this one:
@
function a() { return 3; }
a();
@
I believe, it will return number. Because variant #1 - it's invalid code (E: return operator outside of function) - "return" can be used only in function.

bq. Can I use return-operand in my script code or not?

Yes, you can! But in function, only in function of your script!

In my opinion, you should learn ECMAscript (JavaScript) syntax ;).

0...-5

Ok...and if I have a complex calculation @var a = 1, b = 2;
var c = a + b;
@

and need var c to be returned? Should I use something like

@
function result(var c) {return c;}
result(c);
@

It's a little bit rough.

tucnak

I will give you an example.

script.js
@
function pF( number ) {
return sqrt(number);
}

function pR( number ) {
return number*number;
}

if( pR( pF(25) ) == 25) {
print("I am Qt Script PRO!");
}
@

mainwindow.cpp
@
//...
QString src = scriptFile.readAll();
QScriptValue a = engine.evaluate(src);
if(a.isString())
qDebug() << a.toString();
//...
@

It will print to debug log: "I am Qt Script PRO!".