music21_rs/scale/
mod.rs

1use std::{cmp::Ordering, collections::HashMap};
2
3use crate::{defaults::IntegerType, stepname::StepName};
4
5pub(crate) mod concretescale;
6/// Diatonic scale construction and harmonization helpers.
7pub mod diatonicscale;
8
9pub use diatonicscale::DiatonicScale;
10
11pub(crate) const FIFTHS_ORDER_SHARP: [StepName; 7] = [
12    StepName::F,
13    StepName::C,
14    StepName::G,
15    StepName::D,
16    StepName::A,
17    StepName::E,
18    StepName::B,
19];
20pub(crate) const FIFTHS_ORDER_FLAT: [StepName; 7] = [
21    StepName::B,
22    StepName::E,
23    StepName::A,
24    StepName::D,
25    StepName::G,
26    StepName::C,
27    StepName::F,
28];
29
30pub(crate) fn altered_steps_from_sharps(sharps: IntegerType) -> HashMap<StepName, IntegerType> {
31    let mut map = HashMap::new();
32    match sharps.cmp(&0) {
33        Ordering::Greater => {
34            for step in FIFTHS_ORDER_SHARP.iter().take(sharps as usize) {
35                *map.entry(*step).or_insert(0) += 1;
36            }
37        }
38        Ordering::Less => {
39            for step in FIFTHS_ORDER_FLAT.iter().take((-sharps) as usize) {
40                *map.entry(*step).or_insert(0) -= 1;
41            }
42        }
43        Ordering::Equal => {}
44    }
45    map
46}
47
48pub(crate) fn accidental_modifier_from_alter(alter: IntegerType) -> String {
49    match alter.cmp(&0) {
50        Ordering::Greater => "#".repeat(alter as usize),
51        Ordering::Less => "-".repeat((-alter) as usize),
52        Ordering::Equal => String::new(),
53    }
54}
music21_rs/scale/mod.rs

music21_rs/scale/
mod.rs
