bug#64185: proposal for new function: copy-line

[Mattias Engdegård]

26 juni 2023 kl. 19.37 skrev Juri Linkov <juri@linkov.net>:

> I remember already the need of doing this several times: to create
> initial content for testing first I select one line then duplicate
> its region, then select the whole buffer and duplicate it again
> and so on, so the duplicated region grows exponentially.

Yes, but there is no reason to do that now. Just use duplicate-dwim (or 
duplicate-line).
Both benefit a lot from immediate repeatability.

> `duplicate-dwim-final-column` should be applied to both cases?
> To rectangular regions and to lines?  In case of lines it could
> define whether to keep the original column, or move to the
> beginning of the line, or to the end of the line?

No, I meant the same as you were proposing for lines: whether to insert copies 
before or after the original (or where point and the region should be 
afterwards, but that's pretty much the same thing as long as we preserve 
window-start, as you correctly pointed out).

> Then I think `duplicate-dwim` is a misnomer, and it was misdesigned.
> A proper name that matches the design of `thing-at-point`, would be
> `duplicate-thing`.  thingatpt.el contains the definition of the region
> among many other things that are candidates for duplication.

That is a very different operation. `duplicate-dwim` acts on a buffer area 
designated by the user regardless of its content. The 'thing' functions (there 
seem to be no commands) parse buffer contents to derive a value or extent.

I don't like the 'dwim' name part either but it has some precedence. A single 
function should suffice but since this is Emacs, we have two of them for 
historical reasons before anything is even released.