Writing music

Definitions

Definition : The writing of a music is a translation of event occuring in time in a 2D space representation. (Shall I be more general ? )

Definition : The language is a set of representation that expresses the music. So the rôle of alternate Take is to take Music from one language (XML) to another (the graphical représentation)

Definition : Musical Concepts are the support of languages wether it is a Play, a Score or an XML file. This is the central set of all what we to represent. The best to do is to place the Music Concepts at the center ot the program design.

Definition : The grammar determine whether a representation is correct or not. When writing music you can unable or not the grammar correction. Some grammar correction gives the reader a real comfort some others are a pain. Music has a particular grammar that could be multiple but still understandable. Here we are based on two grammars.

• The XML grammar is realized by the DTD, but it is not sufficient, in music it seems that the rules cannot be restricted to a simple DTD.
• The Graphical grammar : As you will see, this grammar is incredibly complex and full of exceptions. Also, this grammar is not strict this means that you in some case, two writing can be corrects. Thought, Alternate Take will assume that the following rules in graphical represantation :
  • Simultaneity (see below) : Every time will the program is running simultaneity will be respected. So simultaneity is always true in the grammar.
  • Time signature correction (see below) Could be true for editing, but false for final printing or rendering.

Languages

To represent music, we can use several languages as they are not numerous we will always name them :

• Standard notation
• Guitar Tabs
• Bass Tabs
• American notation
• Drum notation

You can mix different languages to write music but the simulaneity is always preserved because we cannot write music without Time.

Also, it is not true that the switch beetween two notations is possible : For instance, Tab Notations give more informations on the fingering of a piece while standard notation give more information on the pitches of a piece. This imply that the underlying musical concept could be partly defined, in this case we call the things we know of a musical concept the projection of it. If a projection is invertible there is no problem, else there are problems. This is a complex problem, but you should be aware that passing from Tab notations to Standard Notation has some consequences on the coherence of the kernel.

Most of the time a language will rely on the instrument you are playing on. At the beginning of Alternate Take were only one notation supported : the classical western music notation.

Anyway, starting with the classical notation will give us a strong background for the other music notations.

Object Organisation