Returned object depends on the nature of the function. It can be integers,
logical, character. Results can be a vector of equal length of a single
value summary.
distinct_notes and distinct_pitches filter a noteworthy string
to its unique elements, respectively. These functions return another
noteworthy string.
The n_* functions give summary totals of the number of timesteps,
number of individual note (non-chord) timesteps, number of chord time
steps, and the number of distinct octaves present across timesteps.
Use the tally_* and distinct_* functions specifically for
summaries of unique elements.
*_span functions are just the size of a range, e.g.,
semitone_range and semitone_span.
Functions pertaining to type or format of a noteworthy string provide
information on how a particular string is defined, e.g. time_format.