Would like the ability to get the result of an activity

Feature description
As pointed out in a similar feature request (#56), you can do intents with am. However, I don't think there's any way to get the returned result of the started activity with am (please correct me if I'm wrong). The reason I want this is that Binary Eye -- and other QR code reader apps -- handle the com.google.zxing.client.android.SCAN intent, scanning a code and return the result of the scan. I would like to be able to use my QR scanner app from within Termux to scan codes and act on them.

Beyond that, this would make Termux more extensible in general since many apps have intent-based APIs that return things.

Background information
Have you checked if the feature is accessible through the android API?
The basic functionality is described here. I don't know much about the android API though and it seems like there might be some complications with actually querying the right data and serializing it appropriately, but to my eyes it seems accessible.

Do you know of other open-source apps that has a similar feature as the one you want? (Provide links)
No.

Start by reviewing the existing am intent functionality and the Android activity-result API linked in the issue, with related context in issue #56. Done should mean a Termux-launched activity can return its result so command-line programs can use it, including the QR-scanning use case.