Not disagreeing but scrolling works just fine in vim/emacs/etc. Wouldn't it be just managing the scroll back buffer yourself rather than the terminals?
Yes, but this does come with differences and tradeoffs. If the terminal isn't managing the scrollback, you don't get scrollbars and you lose any smooth/high resolution scrolling. You also lose fancy terminal features like searching the scrollback, all that needs to be implemented in your application. Depending on the environment it can also wind up being quite unpleasant to use with a trackpad, sometimes skipping around wildly for small movements.
The other part (which IMO is more consequential) is that once the LLM application quits or otherwise drops out of the alternate screen, that conversation is lost forever.
With the usual terminal mode, that history can outlive the Claude application, and considering many people keep their terminals running for days or sometimes even weeks at a time, that means having the convo in your scrollback buffer for a while.
I think they were saying that in "cup" screen mode (CUP: CUrsor Position, activated with smcup termcap), when you exit (rmcup) the text is lost, as well as the history since it was managed by the application, not the terminal.
Their hypothesis was that maybe there was aj intention to have claude code fill the terminal history. And using potentially harzardous cursor manipulation.
In other words, readline vs ncurse.
I don't see python and ipython readline struggling as bad tho...
To clarify: this is the terminal's scrollback buffer vs one managed by the application in the alternate screen.
When I scroll up in nvim, it will keep the editor frame in place (that's the top bar and bottom bar showing things like open buffers, git status, the scratch buffer or whatever it's called), but the file contents will scroll by because nvim at that point has exclusive ownership of the entire screen and can do anything with it, including repainting parts of it in response to motions or a mouse scrolling (if your terminal supports emitting mouse events).
This is in contrast to the `rmcup` "normal" terminal mode where it will scroll back in the terminal's history.
The best analogue I have for that last one is to use tmux with nvim open, and have a tmux visual selection going. You can scroll up and out of nvim, and keep scrolling to whatever was executed before neovim, and when you get out of tmux visual mode it'll snap back down to the bottom of your scrollback buffer, nvim (nominally) taking up the entire pane like nothing happened; but we can probably agree that outside of a few narrow use cases, this isn't a very desirable way to manage scrolling in a terminal.
