Feat: adding some basic music theory

crates/forth/src/theory/chords.rs

@@ -0,0 +1,129 @@
+pub struct Chord {
+    pub name: &'static str,
+    pub intervals: &'static [i64],
+}
+
+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],
+    },
+    // 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],
+    },
+];
+
+pub fn lookup(name: &str) -> Option<&'static [i64]> {
+    CHORDS.iter().find(|c| c.name == name).map(|c| c.intervals)
+}

crates/forth/src/theory/mod.rs

@@ -1,3 +1,4 @@
+pub mod chords;
 mod scales;
 
 pub use scales::lookup;