Thread

The Thread class is the simplest type of Collection. A Thread arranges and accesses its sub-objects in sequential order. When a Thread is requested to produce an event it evaluates its sub-objects, which may involve recursion, to return the next sequential Event.

Heap

The Heap class inherits from Thread but has a specialized output initialization method that shuffles its sub-objects each time it is reset for output processing. By placing objects in a Heap both micro and macro structures to involve random ordering in output realization.

Merge

The Merge class performs parallel access to sub-objects by processing them in a scheduling queue. Merges schedule sub-objects such that inferior Collections are evaluated at the proper local time and that a single time ordered stream of output events results from the merge of the subcollections.

Algorithm

The Algorithm class implements indirect specification of Events from a set of instructions that explain how to change characteristics of the Events over time.

Generator

The Generator class shares characteristics of both Thread and Algorithm. If a Generator already has Events defined for it, it accesses them in sequential order, just like a Thread. But if a Generator does not have any Events, then it runs its Algorithm to create them. This means that musical material may be algorithmically generated but also available for editing afterwards.

Because a Generator's Events may be discarded if they are not wanted, a Generator is particularly useful for generating a series of rough drafts, or for employing random selection in the creation of musical material.

Music Editing

All musical structure in Common Music is persistent, which means that it is available for editing and saving in much the same manner that text may be edited and saved in a word processor. Common Music contains a composition editor, called Stella, that facilitates the creation, editing and processing of musical structure and data. The current version of Stella is non-graphic, which allows the full system to run on any computer that supports Common Music and CLOS, no matter what the display