Cagire/crates/forth/src/theory/chords.rs

//! Chord definitions as semitone interval arrays.

/// Named chord with its interval pattern.
pub struct Chord {
    pub name: &'static str,
    pub intervals: &'static [i64],
}

/// All built-in chord types.
pub static CHORDS: &[Chord] = &[
    // Triads
    Chord {
        name: "maj",
        intervals: &[0, 4, 7],
    },
    Chord {
        name: "m",
        intervals: &[0, 3, 7],
    },
    Chord {
        name: "dim",
        intervals: &[0, 3, 6],
    },
    Chord {
        name: "aug",
        intervals: &[0, 4, 8],
    },
    Chord {
        name: "sus2",
        intervals: &[0, 2, 7],
    },
    Chord {
        name: "sus4",
        intervals: &[0, 5, 7],
    },
    // Seventh chords
    Chord {
        name: "maj7",
        intervals: &[0, 4, 7, 11],
    },
    Chord {
        name: "min7",
        intervals: &[0, 3, 7, 10],
    },
    Chord {
        name: "dom7",
        intervals: &[0, 4, 7, 10],
    },
    Chord {
        name: "dim7",
        intervals: &[0, 3, 6, 9],
    },
    Chord {
        name: "m7b5",
        intervals: &[0, 3, 6, 10],
    },
    Chord {
        name: "minmaj7",
        intervals: &[0, 3, 7, 11],
    },
    Chord {
        name: "aug7",
        intervals: &[0, 4, 8, 10],
    },
    // Sixth chords
    Chord {
        name: "maj6",
        intervals: &[0, 4, 7, 9],
    },
    Chord {
        name: "min6",
        intervals: &[0, 3, 7, 9],
    },
    // Extended chords
    Chord {
        name: "dom9",
        intervals: &[0, 4, 7, 10, 14],
    },
    Chord {
        name: "maj9",
        intervals: &[0, 4, 7, 11, 14],
    },
    Chord {
        name: "min9",
        intervals: &[0, 3, 7, 10, 14],
    },
    Chord {
        name: "dom11",
        intervals: &[0, 4, 7, 10, 14, 17],
    },
    Chord {
        name: "min11",
        intervals: &[0, 3, 7, 10, 14, 17],
    },
    Chord {
        name: "dom13",
        intervals: &[0, 4, 7, 10, 14, 21],
    },
    // Add chords
    Chord {
        name: "add9",
        intervals: &[0, 4, 7, 14],
    },
    Chord {
        name: "add11",
        intervals: &[0, 4, 7, 17],
    },
    Chord {
        name: "madd9",
        intervals: &[0, 3, 7, 14],
    },
    // Power chord
    Chord {
        name: "pwr",
        intervals: &[0, 7],
    },
    // Suspended seventh
    Chord {
        name: "7sus4",
        intervals: &[0, 5, 7, 10],
    },
    Chord {
        name: "9sus4",
        intervals: &[0, 5, 7, 10, 14],
    },
    // Augmented major
    Chord {
        name: "augmaj7",
        intervals: &[0, 4, 8, 11],
    },
    // 6/9 chords
    Chord {
        name: "maj69",
        intervals: &[0, 4, 7, 9, 14],
    },
    Chord {
        name: "min69",
        intervals: &[0, 3, 7, 9, 14],
    },
    // Extended
    Chord {
        name: "maj11",
        intervals: &[0, 4, 7, 11, 14, 17],
    },
    Chord {
        name: "maj13",
        intervals: &[0, 4, 7, 11, 14, 21],
    },
    Chord {
        name: "min13",
        intervals: &[0, 3, 7, 10, 14, 21],
    },
    // Altered dominants
    Chord {
        name: "dom7b9",
        intervals: &[0, 4, 7, 10, 13],
    },
    Chord {
        name: "dom7s9",
        intervals: &[0, 4, 7, 10, 15],
    },
    Chord {
        name: "dom7b5",
        intervals: &[0, 4, 6, 10],
    },
    Chord {
        name: "dom7s5",
        intervals: &[0, 4, 8, 10],
    },
    Chord {
        name: "dom7s11",
        intervals: &[0, 4, 7, 10, 18],
    },
];

/// Find a chord's intervals by name.
pub fn lookup(name: &str) -> Option<&'static [i64]> {
    CHORDS.iter().find(|c| c.name == name).map(|c| c.intervals)
}