Is there a way to make a keypress happen on release of the button? For example, when the left trigger is soft pressed, shift is pressed and released; then when the left trigger is released, shift is pressed and released again.
Also, is there an API somewhere so I could write my own commands/macros?
Yes, but only as custom command. Stuff described on that wiki page should allow you to do some more complicated tasks, and if everything else fails, you can always use shell and run some real script.
Is there a way to make a keypress happen on release of the button? For example, when the left trigger is soft pressed, shift is pressed and released; then when the left trigger is released, shift is pressed and released again.
Also, is there an API somewhere so I could write my own commands/macros?