How can I use my trackpad to scroll left and right, when in
I am running GNU Emacs 25.3.3 (x86_64-apple-darwin13.4.0, Carbon Version 157 AppKit 1265.21) of 2017-09-28.
This is the MacPorts edition by Mitsuharu Yamamoto.
Following the advice of @lawlist (below) I needed to first find out what actions my trackpad left/right swipe are currently bound to (if any). So I entered
C-h k and then scrolled right with my track pad. Here is the message that came back:
<wheel-right> at that spot runs the command mac-mwheel-scroll (found in global-map), which is an interactive compiled Lisp function in ‘term/mac-win.el’. It is bound to <C-wheel-right>, <S-wheel-right>, <wheel-right>, <C-wheel-left>, <S-wheel-left>, <wheel-left>, <C-wheel-down>, <S-wheel-down>, <wheel-down>, <C-wheel-up>, <S-wheel-up>, <wheel-up>. (mac-mwheel-scroll EVENT) Scroll up or down according to the EVENT. Mostly like ‘mwheel-scroll’, but try scrolling by pixel unit if EVENT has no modifier keys, ‘mac-mouse-wheel-smooth-scroll’ is non-nil, and the input device supports it.