The mouse keyword

A basic input component for reading signals from a plugged in mouse.

mouse.mouse_x

This property tells you where the mouse cursor is on the X axis relative to the top left of the game window.

mouse.mouse_y

This property tells you where the mouse cursor is on the Y axis relative to the top left of the game window.

mouse.button_down(button_code)

This method tells you weather one of the mouse buttons are currently pressed. The valid values include MOUSE_LEFT, MOUSE_MIDDLE and MOUSE_RIGHT. Here is how to use it:

if mouse.button_down(MOUSE_LEFT) then
    print('The left mouse button is pressed.')
end