Working with the Keyboard
The modifiers that are held down when the event is generated are combined in a bitwise fashion and provided in the modifiers parameter. The modifier constants defined in arcade.key are:
MOD_SHIFT MOD_CTRL MOD_ALT Not available on Mac OS X MOD_WINDOWS Available on Windows only MOD_COMMAND Available on Mac OS X only MOD_OPTION Available on Mac OS X only MOD_CAPSLOCK MOD_NUMLOCK MOD_SCROLLLOCK MOD_ACCEL Equivalent to MOD_CTRL, or MOD_COMMAND on Mac OS X.
For example, to test if the shift key is held down:
if modifiers & MOD_SHIFT: pass
Unlike the corresponding key symbols, it is not possible to determine whether the left or right modifier is held down (though you could emulate this behavior by keeping track of the key states yourself).