Algorithmic Composition: A Gentle Introduction to Music Composition Using Common LISP and Common Music

1.1 Common LISP

The programming language LISP derives its name from List Processing [Winston, 1989]. Common LISP was developed in 1956 by artificial intelligence researchers Allen Newell, J.C. Shaw, and Herbert Simon [Touretzky, 1990]. Since the early days of LISP, researchers have discovered the power of LISP's processing capabilities for music. Music, a time-based art form, oftentimes is conceived as a succession of events. The events may be a series of pitches, articulation patterns, or a succession of rhythms. Figure 1.1.1 depicts a pitch series that is accompanied by a list representation of that series. Each item in the list representation is called an element.
Figure 1.1.1

List Representation: (C E D F)
Once musical events are described as elements of a list, Common LISP functions may be applied to each element of the list to transform the elements. One such example might be to transpose every element of the list in Figure 1.1.1 up a major second returning the list (D F-sharp E G). Beginning with Chapter 3, we will learn how to use Common LISP to build programs that transform musical data.