A top down (Parsec style) MIDI file parser.

For valid input, the parser should parse without error (i.e all cases of event types are fully enumerated). Malformed input (syntactically bad events, or truncated data) will cause fatal parse errors.

Note - the parser returns a literal result if the input uses Running Status, i.e, - the answer matches the input - where running status uses a NoteOn event with velocity 0 to stand for a NoteOff, the parser likewise returns a Note-On. Use the ZMidi.Core.Canonical to translate the input to canonical form where note-offs are encoded directly with NoteOff.