Line number in multline editing buffer?

[Joep van Delft <joepvandelft@xxxxxxxxx>]

Hi there, 

I did not manage to find a way to determine the current line number
in a multiline buffer (the one after a history operation, so without
the $PS2)? I often put the cursor already somewhere where where I want
to make an edit, and then realize that I'd like to use an editor
instead, and run edit-command-line. I'd fancy the cursor to end up in
the exact same location as it was in the buffer. Would there be a way
to achieve this? 

Thanks! 

Joep