2 Time and Space

The language consists mostly of two parts, reflecting the qualitative difference of time and space dimensions.

• An arithmetic core that can be given both a scalar and a stream semantics, in that basic operators operate on scalar values or infinite stream values, possibly collected in finite, nested spatial arrays.

• A a collection of primitives that allows the creation of causal temporal relations, requiring a stream interpretation of the input/output data.

The design of the temporal primitives is motivated by applications from the domain of musical signal processing (music DSP). Such applications

• rely heavily on the composition of output feedback systems such as linear IIR filters and other state machines, and

• often use a parameter update scheme that executes at a lower sampling rate, i.e. the control rate.

The semantics of the full stream processing language is quite close to that of Faust.