Create and execute a function in a Qt application? [closed] - c++

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I am trying to develop a form that allows users to define variables and use conditions iterations. The form will then pass the texts to the application, where they will be translated and become part of the coding. It's like a template that allows a user to write relatively complex functions. It is more than a calculator because it allows for some programming within the structure. I am using Qt.
I was wondering if this is doable. If so what type of forms and the logic I should use.

Answer 1

It is possible to do it, but the complexity varies depending on where you are aiming at.
For QML it will be quite easy, because it is an interpreted language, it doesn't require compilation, so you can write some code in a text field and execute it.
For C++ it is not as easy, as it is a compiled language, you will have to bundle a compiler with the application, compile the code to a shared library, load it, get a pointer to the function and run it.
In both cases you will need to have a defined interface of the format of data input and linkage to already existing program objects. Based on the wording of your question, your skills may not be quite up to the task yet.
Here is a simple example how to do it in QML:
import QtQuick 2.7
import QtQuick.Window 2.2
import QtQuick.Controls 1.4
Window {
id: main
visible: true
width: 500
height: 300
property int appData : 0
Column {
spacing: 5
Text {
text: "addData is " + appData
}
TextInput {
id: code
width: 500
height: 200
Rectangle {
anchors.fill: parent
border.color: "black"
border.width: 1
z: -1
}
}
Button {
text: "execute"
onClicked: {
var obj = Qt.createQmlObject('import QtQuick 2.0; QtObject { function foo(app) { ' + code.text + ' } }', main)
if (obj) {
obj.foo(main)
obj.destroy()
}
}
}
}
}
Then you can try out executing different statements, as long as they are valid, for example:
app.appData = 5;
app.appData--;
console.log(app.appData);
app.width = 300;