[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[bug#55845] [PATCH 0/1] Improve pager selection logic when less is not i
From: |
Taiju HIGASHI |
Subject: |
[bug#55845] [PATCH 0/1] Improve pager selection logic when less is not installed |
Date: |
Thu, 09 Jun 2022 00:09:16 +0900 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/28.1 (gnu/linux) |
Hi Tobias,
Thank you kindly for your detailed explanation.
Tobias Geerinckx-Rice <me@tobias.gr> writes:
> Hi again,
>
> Taiju HIGASHI 写道:
>> I understand that I can delay the evaluation timing if I make it a
>> procedure, but is my understanding correct that the number of calls
>> will
>> remain the same because it will be evaluated each time the
>> `call-with-paginated-output-port` procedure is called?
>
> Previously, it would have been evaluated even if
> call-with-paginated-output-port was never called at all.
>
> As for the >0 calls case: yes… but when do we expect
> call-with-paginated-output-port to be called more than once per run?
>
> The use case for this code is to do something, then display it in a
> pager and exit. I think calling it multiple times in one run would
> imply bad UX.
>
> Do I misunderstand?
No, you don't.
As you said, my implementation was a bad idea, as
call-with-paginated-output-port is executed even when it is not needed.
It seems unlikely that call-with-paginated-output-port will be called
more than once in a single process. I did not have enough insight.
>> I agree with your point that it would be better to make it a
>> procedure,
>> as it would be more eco-friendly to not have to evaluate when
>> GUIX_PAGER
>> or PAGER is specified.
>
> I wish the rest of Guix were so efficient that it mattered :-)
>
> [/me is waiting for ‘guix pull’ as I reply to multiple mails, on
> battery…]
>
> Regardless, not calling a procedure at all is even more efficient and
> IMO more readable here.
I agree.
>> You mean that the $PATH lookup in open-pipe can be suppressed?
>
> Yes. OPEN-PIPE* won't need to stat $PATH at all if we give it
> "/run/current-system/profile/bin/less" instead of "less".
>
> (It's not relevant to the above, but my previously reply mistakenly
> mentioned a shell ― there is no shell involved with OPEN-PIPE*, only
> with OPEN-PIPE. Sorry.)
No problem. I'm sorry I'm the one who asked a ton of questions.
>> I will just write what you have told me, but may I continue to
>> modify
>> the patch?
>
> Of course! Curious how, though.
I have also received a response from Maxime and plan to include the
following information.
(define (find-available-pager)
"Returns the program name or path of an available pager.
If neither less nor more is installed, return an empty string so that
call-with-paginated-output-port will not call pager."
(or (getenv "GUIX_PAGER")
(getenv "PAGER")
(which "less")
(which "more")
"" ;; Returns an empty string so that call-with-paginated-output-port
does not call pager.
))
(define* (call-with-paginated-output-port proc
#:key (less-options "FrX"))
(let ((pager-command-line (find-available-pager)))
...
However, I can't submit the v2 patch yet because I don't know how to
implement the integration test.
Thanks,
--
Taiju
[bug#55845] [PATCH 0/1] Improve pager selection logic when less is not installed, Tobias Geerinckx-Rice, 2022/06/08