Many system, musical and mathematical rules can be called within the script, which also supports reading and writing data files, creating procedures whereby sets of modules can be created, MIDI In and MIDI Out, defining MIDI voices and channels, scheduling of events, etc. Tabula Vigilans is a powerful and evolving tool ideal for composers with an interest in programming and in rule-based score generation. It is sold as a separate, optional program.
Algorithmic composition can relate either to tone generation, or to score generation.
These can range from defined melodic sequences to arbitrarily complex musical textures. Tabula Vigilans is conceived like a musical spreadsheet in that it 'recalculates' the page at machine speed. This means that any variable or combination of variables can be updated at any time. Tabula Vigilans is therefore aptly described as a real-time performance instrument . This makes it particularly useful for handling the information that controls 'expressiveness' in music.