Subject: bug#56779: 29.0.50; [wishlist] Function to check if a mouse-button is pressed

From: Visuwesh <[email-masked]>
Date: Tue, 26 Jul 2022 14:28:46 +0530

Currently, to know if a mouse button is being pressed, one has to keep
track of state by cleverly utilising [down-mouse-N] and [mouse-N] events
(see [1]).  It is certainly no easy task, it would be really nice if
Emacs had the equivalent of `xinput --query-state <mouse-id>' [2]
(the implementation of which can be found in state.c in xinput's
source).

The reason I ask this is because I would really like to have mouse
chording in Emacs but currently it is too hard to implement it (BTW,
mouse-copy.el talks about mouse-chording).

    1. https://github.com/akrito/acme-mouse
    2. All you need to do is,
           % xinput --query-state <mouse-id> |sed -n 's/[ \t]\+button\[1\]=//p'
       to get the state of mouse-1.

In GNU Emacs 29.0.50 (build 26, x86_64-pc-linux-gnu, X toolkit, Xaw scroll bars)
 of 2022-07-22 built on astatine
Repository revision: 12a3137cd381cb743768033e789b900b015041d7
Repository branch: master
Windowing system distributor 'The X.Org Foundation', version 11.0.12101003
System Description: Debian GNU/Linux bookworm/sid

Configured using:
 'configure --with-sound=alsa --with-x-toolkit=lucid --with-json
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Configured features:
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Important settings:
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