\section{The Architecture of Haskore} \figref{haskore} shows the overall structure of Haskore. Note the independence of high level structures from the ``music platform'' on which Haskore runs. Originally, the goal was for Haskore compositions to run equally well as conventional midi-files \cite{midi}, NeXT MusicKit score files \cite{musickit} \footnote{The NeXT music platform is obsolete.}, and CSound score files \cite{csound} \footnote{There also exists a translation to CSound for an earlier version of Haskore.}, and for Haskore compositions to be displayed and printed in traditional notation using the CMN (Common Music Notation) subsystem. \footnote{We have abandoned CMN entirely, as there are now better candidates for notation packages into which Haskore could be mapped.} In reality, three platforms are currently supported: MIDI, CSound, and some signal processing routines written in Haskell. For musical notation an interface to Lilypond is currently in progress. \begin{figure*} \centerline{ \includegraphics[height=4.0in]{Doc/Pics/haskore} } \caption{Overall System Diagram} \figlabel{haskore} \end{figure*} In any case, the independence of abstract musical ideas from the concrete rendering platform is accomplished by having abstract notions of \keyword{musical object}, \keyword{player}, \keyword{instrument}, and \keyword{performance}. All of this resides in the box labeled ``Haskore'' in the diagram above. At the module level, Haskore is organized as follows: \begin{haskelllisting}
> module Haskore (module Haskore,
>                 module Haskore.Music,
>                 module Haskore.Performance,
>                 module Haskore.Performance.Player,
>                 module Haskore.Interface.MIDI.Write,
>                 module Haskore.Interface.MIDI.Read,
>                 module Sound.MIDI.File.Save,
>                 module Sound.MIDI.File.Load,
>                 module Haskore.Interface.MIDI.Render)
>        where
> import qualified Haskore.Music
> import qualified Haskore.Performance
> import qualified Haskore.Performance.Player
> import qualified Haskore.Interface.MIDI.Write
> import qualified Haskore.Interface.MIDI.Read
> import qualified Sound.MIDI.File.Save
> import qualified Sound.MIDI.File.Load
> import qualified Haskore.Interface.MIDI.Render
\end{haskelllisting} \begin{comment}
> import Prelude hiding (repeat, reverse)
\end{comment} This document was written in the \keyword{literate programming style}, and thus the \LaTeX\ manuscript file from which it was generated is an \keyword{executable Haskell program}. It can be compiled under \LaTeX\ in two ways: a basic mode provides all of the functionality that most users will need, and an extended mode in which various pieces of lower-level code are provided and documented as well (see file header for details). This version was compiled in \basic{basic}\extended{extended} mode. The document can be retrieved via WWW from: \url{http://haskell.org/haskore/} (consult the README file for details). It is also delivered with the standard joint Nottingham/Yale Hugs release. The Haskore code conforms to Haskell 1.4, and has been tested under the June, 1998 release of Hugs 1.4. Unfortunately Hugs does not yet support mutually recursive modules, so all references to the \module{Player} in this document are commented out, which in effect makes it part of \module{Performance} (with which it is mutually recursive). A final word before beginning: As various musical ideas are presented in this Haskore tutorial, I urge the reader to question the design decisions that are made. There is no supreme theory of music that dictates my decisions, and what I present is actually one of several versions that I have developed over the years (this version is much richer than the one described in \cite{haskore}; it is the ``Haskore in practice'' version alluded to in \secref{midi} of that paper). I believe that this version is suitable for many practical purposes, but the reader may wish to modify it to better satisfy her intuitions and/or application.