This seems to be a good week for LISP-based algorithmic composition software.
An open-source, specialised algorithmic composition programme written in the general programming language Common Lisp and its object-oriented extension, CLOS, “slippery chicken” has been in development since 2000. By specialised as opposed to generalised, it is meant that the software was originally tailor-made to encapsulate the author’s personal composition techniques and to suit his own compositional needs and goals. As the software has developed however, many general-purpose algorithmic composition tools have been programmed that should be useful to a range of composers. The system does not produce music of any particular aesthetic strain; for example, although not programmed to generate tonal music the system is quite capable of producing it. Furthermore, the software’s release as open-source, object-oriented Common Lisp code encourages further development and extensions on the part of the user.
PWGL is a free cross-platform visual language based on Common Lisp, CLOS and OpenGL, specialized in computer aided composition and sound synthesis. It is programmed using the Lispworks programming environment.
PWGL integrates several programming paradigms (functional, object-oriented, constraint-based) with high-level visual representation of data and it can be used to solve a wide range of musical problems. PWGL is based on many concepts and ideas that were originally developed for PatchWork (Laurson, Rueda, Duthen, Assayag, Agon) and thus credit should be given to numerous programmers, composers and researchers that were involved in this project. PWGL is developed at Sibelius Academy in Finland by a research team consisting of Mikael Laurson, Mika Kuuskankare, and Vesa Norilo. Recently the team has been augmented by Kilian Sprotte.