Strasheela is a highly expressive constraint-based music composition system. Users declaratively state a music theory and the computer generates music which complies with this theory. A theory is formulated as a constraint satisfaction problem (CSP) by a set of rules (constraints) applied to a music representation in which some aspects are expressed by variables (unknowns). Music constraint programming is style-independent and is well-suited for highly complex theories (e.g. a fully-fledged theory of harmony). Results can be output into various formats including MIDI, Lilypond, and Csound.