I have two files open, shown in two windows.
Some lines in one file belong in the other file.
I could cut the line here, move to the other window, paste there, and come back. That's a lot of work with so many lines to go through.
There does not seem to be any existing command that would do the work, so how do I write an elisp function (or macro?), and bind it to an available key/chord, to do that?
This is similar to the problem solved by diff-mode and the like, but the files here are not related, so a diff doesn't make sense.
[edit 1] very good point raised by @StarBug. I see several possibilities (a configuration variable?), listed from top to bottom: a. move at the top, b. move at point, c. move to 'same' line on screen, d. move to bottom.
[edit 2] fixed the confusion between frame and window.