HMSL, the Hierarchical Music Specification Language 

    HMSL is an experimental programming language that is an
    extension to Forth.  It was developed at the Center for
    Contemporary Music at Mills College by Phil Burk, Larry
    Polansky, and David Rosenboom.  It is distributed by Frog Peak
    Music.  

    HMSL, the Hierarchical Music Specification Language, is a
    programming language for experimental music composition and
    performance.  It is an object oriented set of extensions to the
    Forth language that runs on the Macintosh (Plus , SE and II) and
    Amiga computers with 1 Meg or more of RAM.  HMSL includes tools
    for exploring algorithmic composition, intelligent real time
    instrument design, and musical cognition and perception.  It
    also provides a complete MIDI toolbox including a MIDI parser
    that can give a programmed response to any MIDI input event.  

    HMSL is used by a number of composers who want to explore the
    uncharted regions of music.  It has been used for everything
    from enhancing keyboard performance, to interspecies
    communication experiments, to controlling kinetic sculptures, to
    generating music based on fractals.  

    HMSL provides a number of classes of musical objects including
    one that allows you to treat musical parameters as abstract
    numeric "shapes".  Shapes can represent melodies, profiles of
    harmonic complexity, intervals or any other user defined
    parameter.  These shapes can be edited graphically while being
    performed.  Shapes are played by objects called Players that
    provide very flexible real time scheduling.  Players use objects
    called Instruments that output the shape data in some way,
    either as music, or text or graphics, or ...  Players can be
    assembled with other Players in Parallel or Sequential
    Collections.  Collections can also contain other Collections to
    build very complex hierarchical  pieces.  One can also place
    Productions and Jobs in the hierarchy which will execute user
    written routines.  

    An additional real time performance environment, called Perform,
    allows you to turn on or off, or change the priority of
    Actions.  Actions are customizable objects that have a
    programmed response to a programmed stimulus.  This environment
    can be used for complex performance "webs".  

    The Amiga version also provides a toolbox for local sound
    generation, IFF sample playback and editing, and alternate
    tunings based on ratios or precalculated periods.  

    Use of HMSL requires some software programming skills, however,
    an extensive manual, tutorial, and many sample pieces are
    included to help people get started.  HMSL comes in source code
    form and must be compiled.  HMSL costs $150.00.  

    Frog Peak Music
    P.O. Box 9911
    Oakland, CA
    94613

    (415) 461-1442

    Bitnet: phil@mills.berkeley.edu