bug#63778: [PATCH] Use comint-pager in eshell

[Jim Porter <jporterbugs@gmail.com>]

On 5/28/2023 7:26 PM, Morgan Smith wrote:
>> I haven't the time left in the day to investigate the conflict between
>> visual commands and this patch (which I will do) but I would like to
>> comment that I believe most users will use one or the other, not both.
>> Unless pagers offer features I'm unaware of, I believe it is a better
>> user experience to simply dump everything into the current buffer and
>> use Emacs as a pager.  For very visual command like pulsemixer that use
>> ncurses stuff I don't believe having $PAGER set would really affect
>> anything.  So I would like to ask, does anyone actually want to use the
>> visual command stuff just for paging stuff?

I'm not personally a fan of visual commands in Eshell, but the docstring 
for 'eshell-visual-subcommands' suggests adding the various Git 
subcommands that invoke a pager into that list, so it seems that Eshell 
*assumes* people would want this, at least...

>> I would also like to point out that the default value for comint-pager
>> is nil so people would have to turn this on manually.  If the usecase
>> for comint-pager is significantly different between eshell and other
>> comint stuff we could consider a new variable specifically for eshell.
>> Personally I don't see a big difference between say ielm and eshell so I
>> would like to avoid this but I'll bring it up regardless.

Ah, in that case, then I think you'd want to change the logic in 
esh-var.el so that, when 'comint-pager' is nil, $PAGER returns the real 
value of PAGER from the environment. Since this behavior is opt-in, I 
think it would be enough to just make this fix (and ignore the visual 
command stuff), though special handling for visual commands would still 
be nice to have.