Object audio-player provides an abstraction barrier between the external interface to the sound space and the underlying implementation -the interface only deals with object audio-player. An audio-player consists of a sound to be played, a function to play the sound and a switch to turn the sound on and off. Once an audio player object has been created, its sound can be changed, and it can also be turned on and off using its switch. The external interface to the sound space maps points to the state of the underlying audio player. We can think of object audio-player as the underlying hardware for the sound component of the audio space. Thus, we could have one audio-player for each audio component. Object audio-player is implemented so as to allow the use of other sound generation software that becomes available in the future. Given a function [tex2html_wrap5598] that generates sound when called with argument [tex2html_wrap5600], we can create an audio player with function [tex2html_wrap5602] and sound [tex2html_wrap5604] to create a uniform interface to the underlying sound generation software.
AFL blocks and assignments are used to manipulate the external representation of the state of the subspace, and the underlying hardware representation, in this case the audio-player, is automatically updated.