FAUST

FAUST (Functional AUdio STream) is a domain-specific purely functional programming language for implementing signal processing algorithms in the form of libraries, audio plug-ins, or standalone applications. A FAUST program denotes a signal processor: a mathematical function that is applied to some input signal and then fed out. FAUST (Functional AUdio STream) is a domain-specific purely functional programming language for implementing signal processing algorithms in the form of libraries, audio plug-ins, or standalone applications. A FAUST program denotes a signal processor: a mathematical function that is applied to some input signal and then fed out. The FAUST programming model combines a functional programming approach with a block diagram syntax: A FAUST program doesn’t describe a sound or a group of sounds, but a signal processor. The program source is organized as a set of definitions with at least the definition of the keyword process (the equivalent of main in C): The FAUST compiler translates FAUST code into a C++ object, which may then interface with other C++ code to produce a full program. The generated code works at the sample level. It is therefore suited to implement low-level DSP functions like recursive filters. The code may also be embedded. It is self-contained and does not depend on any DSP library or runtime system. It has a very deterministic behavior and a constant memory size. The semantics of FAUST is driven to be simple and well-defined. It allows the FAUST compiler to be semantically driven. Instead of compiling a program literally, it compiles the mathematical function it denotes. This may promote component reuse. Moreover, having access to the exact semantics of a FAUST program can simplify preservation issues. FAUST is a textual language but block diagram oriented. It combines two approaches: functional programming and algebraic block diagrams, which are constructed via function composition. For that, FAUST relies on a block diagram algebra of five composition operations. FAUST programs define a process function that operates on incoming data. This is analogous to the main function in most programming languages. The following is an example that produces silence: The second example copies the input signal to the output. It involves the _ primitive that denotes the identity function for signals: