bug#57367: [PATCH] Speed up em-smart

[Jim Porter <jporterbugs@gmail.com>]

On 9/4/2022 2:56 PM, Lars Ingebrigtsen wrote:
> Morgan Smith <Morgan.J.Smith@outlook.com> writes:
> 
>> em-smart is very slow.  This patch makes it much faster.  idk why there
>> was all this redisplay stuff in the module as everything seems to work
>> great when I remove it all.
> 
> Skimming the patch, I think it makes sense, but I'm not that familiar
> with eshell.  Perhaps Jim has some comments; added to the CCs.

I don't know much about the smart scrolling module in Eshell, but I'll 
try to familiarize myself with it and then take a look. I'm slightly 
hesitant about deleting a bunch of code until I know why it was there in 
the first place; from the comments in em-smart.el, it sounds like these 
hooks are intentional:

   ;; @ While output is being generated from a command, the window will
   ;;   be constantly reconfigured (until it would otherwise make no
   ;;   difference) in order to always show you the most output from the
   ;;   command possible.  This happens if you change window sizes,
   ;;   scroll, etc.

However, maybe there's a better way to do this, or failing that, to at 
least provide some more options in the module so that users can tune the 
performance to their liking.