Plugin syntax, looping, and language issues

I don't understand what you mean, but think you migfht still be confused. Of course the second segment in my example contains nothing for the first staff - because there *is* nothing for first staff at that tick. If you wish to write a plugin to figure out a chord name for tick 960, it will simply be up to you to remember that there there was a chord at tick 0 (or search backwards for it). It's no different from how you'd do it looking at the actual printed score. You'd see a note on the second staff on beat 3, and nothing on beat three in the first staff. You'd have to remember you already saw a note on beat 1, or else look backwards for it. Thius isn't some arbitrary limitation of the plugin framework or the MuseScore core representation, it's just plain common sense. Which is what me think you must still be fundamentally misunderstanding something. We can't make there be something on beat 3 in staff 1 if there *isn't* anything on beat in staff 1!

Tongkam, hang in there. First of all, if you are familiar with JavaScript, you should be able to figure out QML eventually. It really isn't that complicated, and in fact allows you to use JavaScript function calls (the String split() function I used above is a JavaScript function).

Secondly, do some basic research on object-oriented programming and pointers (they are related concepts) - since you said you did not understand them. The basic concepts aren't that difficult, and looking at the QML code will make a lot more sense if you realize what's going on with the objects and references to them.

For example, in heuchi's code above, the variable "cursor" is a reference to a Cursor object (the Cursor class defines the Cursor object type). If you look at the documentation for the Score class in the plugin creator (? = Manual), you will see that it has a method called newCursor(), which is where you get the cursor pointer. MuseScore's implementation of QML gives you a pointer to the current Score object (curScore), so you can write code like this:

var cursor = curScore.newCursor();
var segment = cursor.segment;
var element = cursor.element;

The element is a single element on a single track. The cursor moves along from segment to segment on a single track (each track equals a voice on a staff) - cursor.next() moves to the next segment in the score, cursor.rewind(n) moves to the beginning of the selection, end of selection, or beginning of score, depending on value of n, cursor.staffIdx indicates the current staff, and cursor.voice indicates the current voice. So when you iterate through the score using the Cursor object, you can move left to right (assuming you use cursor.next()) on a single track, rewind to the beginning and set the next track, staff, etc.

If you are interested in all of the notes at a given moment of time, you can get that with the Segment object (as heuchi showed in the code above), and can ignore the cursor completely. In this case, you get the first segment of the score from the Score object (see heuchi's code). You would probably initialize the variable firstTrack = 0, and lastTrack = curScore.ntracks - 1 (notice that the Score object has the property ntracks with type int). In other words, heuchi's code stops at each segment, and then iterates down through every track in that segment, looking for every element. The if (element) {...} conditional is there because if there is no element on a track, you will get a null pointer and the plugin will crash. Since you are interested in notes and not other types of elements, you use the if (element.type == Element.CHORD) to filter for Chord objects only. But you still need to see how many notes that Chord represents - it could be as few as 1, or any other number. The Note objects are held in the Chord.notes array (also see that the property "notes" is defined in the Chord class description in the Manual).

Also note that "track" and "voice" are related. MuseScore assigns 4 voices per staff, first staff in a system has tracks 0 - 3, second staff 4 -7, and so on.