Module base40 

Walter Hewlett’s base-40 pitch numbers: music21’s musedata.base40.

Base 40 numbers every pitch from a double flat to a double sharp on each of the seven letters, forty to the octave, leaving a number unused between two letters a whole step apart. Its gift is that the distance between two numbers names the interval between the pitches, spelling and all: 23 is always a perfect fifth.

use music21::musedata::base40;

assert_eq!(base40::pitch_name(186), Some("G"));
assert_eq!(base40::from_pitch_name("F##", 4), Some(142));
assert_eq!(base40::delta_to_interval(-52).unwrap().directed_name(), "M-10");

Structs

Base40Error

Why a base-40 question has no answer, in music21’s words: what music21 raises as Base40Exception.

Enums

Direction

The way an enharmonic is looked for: a diminished second up or down.

Constants

EQUIVALENTS

music21’s base40Equivalent: the pitch name each number of an octave stands for, from 1 to 40, and the empty name for the five unused.

INTERVALS

music21’s base40IntervalTable: the simple interval each distance within an octave is. A distance missing here is no interval base 40 can say.

Functions

actual_interval

music21’s base40ActualInterval: the interval between the pitches two base-40 numbers are, worked out from the pitches rather than read from the distance.

delta_to_interval

music21’s base40DeltaToInterval: the interval a distance between two base-40 numbers is, its octaves counted and its direction kept.

equivalent

The pitch name a number of the octave (1 to 40) stands for, the empty name for one unused, and None for a number outside the octave.

from_pitch

music21’s pitchToBase40: a pitch’s base-40 number.

from_pitch_name

The base-40 number of a pitch name in an octave, as music21’s pitchToBase40 numbers it: octave 1’s C double flat is 1.

interval

music21’s base40Interval: the interval between two base-40 numbers, read from their distance alone.

octave_and_number

The octave and the number within it music21’s base40ToPitch reads a base-40 number as. music21 divides with a float and lets the octave setter drop the fraction, so the octave is the quotient cut toward nought, and the number within it is what is left after that many octaves.

pitch_name

The pitch name a base-40 number stands for, in whatever octave: None for one of the unused numbers.

quick_enharmonic_string

music21’s quickEnharmonicString: the lower spellings, then the higher.

quick_enharmonics

music21’s _quickEnharmonicString: the other spellings of a pitch name one way, each a diminished second from the last, until a letter comes round again or base 40 runs out of names. double_accidentals false leaves the double sharps and flats out.

representation

music21’s base40Representation: the number of the octave a pitch name is, for the thirty-five names base 40 has.

to_pitch

music21’s base40ToPitch: the pitch a base-40 number is.