Virtual Devices

Devices can be classified according to the kind of value they return:

Button:

Return a Boolean value; can be depressed or released.

Key:

Return a ``character''; that is, one of a given set of code values.

String:

Return a sequence of characters.

Selector:

Return an integral value (in a given range).

Choice:

Return an option (menu, callback, ...)

Valuator:

Return a real value (in a given range).

Locator:

Return a position in (2D/3D) space (eg. several ganged valuators).

Stroke:

Return a sequence of positions.

Pick:

Return a scene component.

Each of the above is called a virtual device.