Edit 2024-02-05:
The instructions below are outdated.
There is an official PR (#2027) for mouse functionality. You should use that rather than what is described below.
Gavin Sinclair, January 2022
I use Karabiner (configured with Gosu) to make advanced key mappings on my Apple computer. Karabiner allows you to create “layers”, perhaps simulating those on a programmable mechanical keyboard. I make good use of these layers to give me easy access (home-row or nearby) to all symbols and navigational controls, and even a numpad.
The motivation is to keep hand movement to a minimum. Decades of coding on standard keyboards has unfortunately left me with hand and wrist pain. I will soon enough own a small split keyboard which will force me to use layers to access symbols etc., so this Karabiner solution, which has evolved over months, is a training run for that.