Key is the left arrow key?

Property definitions

mnit $ KeyEvent :: is_arrow_left
	# Key is the left arrow key?
	fun is_arrow_left: Bool is abstract
lib/mnit/input.nit:86,2--87,36

gamnit $ GamnitKeyEvent :: is_arrow_left
	redef fun is_arrow_left do return native.keysym.is_left
lib/gamnit/gamnit_linux.nit:124,2--56