tabr (version 0.4.0)

note_slice: Slice, sort, rotate, shift and arpeggiate notes

Description

Helper functions for indexing and moving notes within noteworthy strings.

Usage

note_slice(notes, ...)
note_sort(notes, decreasing = FALSE)
note_rotate(notes, n = 0)
note_shift(notes, n = 0)
note_arpeggiate(notes, n = 0, step = 12)

Arguments

notes

character, a noteworthy string, space-delimited or vector of individual entries.

...

For note_slice, an integer or logical vector.

decreasing

logical, short in decreasing order.

n

integer, number of rotations or extensions of note sequence. See details.

step

integer, number of semitone steps from the first (or last) note in notes at which to begin repeating the shifted notes sequence as an arpeggio. See examples. arpeggio.

Value

character

Details

note_slice subsets the timesteps of a noteworthy string by integer index or logical vector of length equal to the number of timesteps.

note_sort sorts the timesteps of a noteworthy string by pitch. When a tie exists by root note, the next note in chords are compared, if they exist. For example, a, sorts lower than a,ce.

note_rotate simply rotates anything space-delimited or vectorized in place. It allows chords. Octave numbering is ignored if present.

For note_shift the entire sequence is shifted up or down in pitch, as if inverting a broken chord. If notes contains chords, they are broken into successive notes. Then all notes are ordered by pitch. Finally shifting occurs.

Instead of a moving window, note_arpeggiate grows its sequence from the original set of timesteps by repeating the entire sequence n times (n must be positive). Each repeated sequence contributing to the arpeggio is offset by step semitones from the original. step can be negative. It defaults to 12, increasing all notes by one octave.

Examples

# NOT RUN {
x <- "bd'f#' a c'e'g' b ba c'g' gd'g'd''"
note_sort(x)
note_sort(x, decreasing = TRUE)

x <- "e_2 a_, c#f#a#"
note_slice(x, 2:3)
note_slice(x, c(FALSE, TRUE, TRUE))

note_rotate(x, 1)

note_shift("c e g", 1)
note_shift("c e g", -4)

note_arpeggiate("c e g ceg", 3)
note_arpeggiate("c e g", 3, step = -12)
note_arpeggiate("g e c", 3, step = -12)
note_arpeggiate("c e_ g_ a", 3, step = 3)
note_arpeggiate("c a g_ e_", 3, step = -3)
# }