Add Note type with duration and rests (#9)

Author: dpsanders

src/MusicTheory.jl

@@ -17,11 +17,14 @@ export Chord
 
 export make_triad, is_triad
 
+export Note, rest
+
 
 include("pitches.jl")
 include("pitch_names.jl")
 include("intervals.jl")
 include("scales.jl")
 include("chords.jl")
 include("triads.jl")
+include("notes.jl")
 end

src/notes.jl

@@ -0,0 +1,23 @@
+
+struct Rest end
+
+const NoteTypes = Union{Pitch, Chord{Pitch}, Rest}
+
+"""
+    struct Note
+
+A note is a pitch and a duration.
+The pitch can be a chord, or a rest
+"""
+struct Note
+    pitch::NoteTypes
+    duration::Rational{Int}
+end
+
+# use / and * to specify durations:
+Base.:(/)(p::NoteTypes, n::Int) = Note(p, 1 // n)
+Base.:(*)(p::NoteTypes, n::Rational{Int}) = Note(p, n)
+
+const rest = Rest()
+
+

test/notes.jl

@@ -1,9 +1,18 @@
-using MusicTheory.PitchNames
+@testset "Notes with durations" begin
 
-@testset "Notes" begin
-    note = C[4]
+    using MusicTheory.PitchNames
 
-    @test PitchClass(note) == C
-    @test accidental(note) == ♮
-    @test octave(note) == 4
-end
+    n = C[4] / 8
+    @test n isa Note
+    @test n.pitch == C[4]
+    @test n.duration == 1 // 8
+
+    n = B[5] * 3 // 8
+    @test n.pitch == B[5]
+    @test n.duration == 3 // 8
+
+    n = rest / 4
+    @test n isa Note
+    @test n.pitch == rest
+    @test n.duration == 1 // 4
+end

test/pitches.jl

@@ -0,0 +1,9 @@
+using MusicTheory.PitchNames
+
+@testset "Pitches" begin
+    note = C[4]
+
+    @test PitchClass(note) == C
+    @test accidental(note) == ♮
+    @test octave(note) == 4
+end