Question: intended behavior scriptThread.stopScript()

[Flo]

When developing a script today, I wanted to stop execution when the user cancels a selection in a combo box.
I called scriptThread.stopScript() but the execution did not stop (ran into an exception since the lookup of the non existent / empty selected value failed)

What is the intended way to completely stop the execution of a script? Is this possible at all? Or do I need to build a big chain of if/else to make sure I do not run into issues with not selected values?

[Stefan Zieker]

scriptThread.stopScript() is the function to stop a script. Maybe you can upload your script and I can debug it.

[Flo]

Here a simple example

const list = ["a", "b", "c"]

function getListItem() {
  const input_string = scriptThread.showGetItemDialog("Select", "test", list)
  if (input_string == "") {
    scriptThread.messageBox("Error", "Select", "Required")
    scriptThread.stopScript()
    return null
  }

  return list.indexOf(input_string)
}

var t = getListItem()
scriptThread.messageBox("Info", "Selected", t.toString())

Note: when I am not using a function the script also doesn't stop immediately (in this case it would show index -1 and not have an exception)

Screen.Recording.2022-07-25.at.09.00.45.mov

[Stefan Zieker]

The reason for the exception is return null. null is an undefined object. If you call a function (toString()) from an undefined object an exception is thrown. If you change null for example to -1 (number object) then the exception does not occur.

[Flo]

My understanding was, the script would immediately abort after the stop and would never reach the line where it tries to deference the null? But from your explanation it sounds like the script will always continue to the end and there is no early exit? (This was not clear to me from the documentation and examples) So if it is like this, calling stop in the middle of a script is not a pattern, just at the end is sufficient (given it had no endless loop). Correct?

…

On Mon 25. Jul 2022 at 17:50 Stefan Zieker ***@***.***> wrote: The reason for the exception is return null. null is an undefined object. If you call a function (toString()) from an undefined object an exception is thrown. If you change null for example to -1 (number object) then the exception does not occur. — Reply to this email directly, view it on GitHub <#38 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ADDCR7UOJ6NWDM234OYMCALVV2ZURANCNFSM54JGFE4Q> . You are receiving this because you authored the thread.Message ID: ***@***.*** com>

[Stefan Zieker]

To be honest, I thought stopScript would exit the script directly because it calls the exit function of the thread which executes the script (every script is executes in its own thread). But the code that is not in a slot function (slot functions are called if a signal is emitted (e.g. from a timer or data reception)) is executed by the script interpreter before the exec function of the thread is called. In other words, if you call stop script in code that is not in a slot function then the script does stop if the end of the script is reached, if called in a slot function the script stops immediately.
I will change this behavior in the next release (if I cannot change it then I will describe it in the documentation).

[Stefan Zieker]

Hi,
I fixed this issue (on the master branch). If a script calls stopScript then the execution is stopped immediately. I will create a new release next week.
Sorry for fixing this so late, I was really busy the last months.