Add Base.keys() and is_octave() (#156)

* add Base.keys * add is_octave * is_octave doc * add markdown link * add is_octave test * add base.eachindex, add find max test, wait reply * add is_octave() for pitch * finish find max pitch note doc and test * change log for keys and eachindex * Update src/note.jl Co-authored-by: George Datseris <[email protected]>
JuliaMusic · Dec 11, 2022 · 4554c16 · 4554c16
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -4,6 +4,9 @@ All notable changes to this project will be documented in this file.
 
 The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
 and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html).
+# v2.3.0
+* New functions `is_octave`.
+* Implement `Base.keys(::Notes)` and `Base.eachindex(::Notes)`.
 # v2.2.0
 * New functions `pitch_to_hz ` and `hz_to_pitch `
 # v2.1.0

diff --git a/Project.toml b/Project.toml
@@ -1,7 +1,7 @@
 name = "MIDI"
 uuid = "f57c4921-e30c-5f49-b073-3f2f2ada663e"
 repo = "https://github.com/JuliaMusic/MIDI.jl.git"
-version = "2.2.0"
+version = "2.3.0"
 
 [deps]
 FileIO = "5789e2e9-d7fb-5bc7-8068-2c6fae9b9549"

diff --git a/src/MIDI.jl b/src/MIDI.jl
@@ -30,7 +30,7 @@ export BPM, bpm, qpm, time_signature, tempochanges, ms_per_tick
 export getnotes, addnote!, addnotes!, addevent!, addevents!
 export MIDITrack
 export Note, Notes, AbstractNote, DrumNote
-export pitch_to_name, name_to_pitch
+export pitch_to_name, name_to_pitch, is_octave
 export pitch_to_hz, hz_to_pitch
 export TrackEvent, MetaEvent, MIDIEvent, SysexEvent
 export readvariablelength, writevariablelength

diff --git a/src/note.jl b/src/note.jl
@@ -73,6 +73,12 @@ A data structure describing a collection of music notes, bundled with the ticks
 per quarter note (so that the notes can be attributed rhythmic value).
 
 `Notes` can be iterated and accessed as the given `note_vector`.
+This eliminates the need for custom iteration or search functions.
+For example, to get the note of maximum pitch you can do:
+```julia
+max_pitch, index_max = findmax(n -> n.pitch, notes)
+max_pitch_note = notes[index_max]
+```
 """
 struct Notes{N <: AbstractNote}
     notes::Vector{N}
@@ -101,6 +107,8 @@ Base.firstindex(n::Notes) = firstindex(n.notes)
 Base.getindex(n::Notes, i::Int) = n.notes[i]
 Base.getindex(n::Notes, r) = Notes(n.notes[r], n.tpq)
 Base.view(n::Notes, r) = view(n.notes, r)
+Base.eachindex(n::Notes) = eachindex(n.notes)
+Base.keys(n::Notes) = eachindex(n)
 
 # Pushing
 Base.push!(no::Notes{N}, n::N) where {N <: AbstractNote} = push!(no.notes, n)
@@ -112,6 +120,12 @@ end
 
 Base.copy(notes::Notes) = Notes([copy(n) for n in notes], notes.tpq)
 
+"""
+    is_octave(note1::Note, note2::Note)
+Return true if two notes form an octave.
+"""
+is_octave(note1::Note,note2::Note)::Bool = abs(Int(note1.pitch)-Int(note2.pitch)) == 12
+is_octave(pitch1::Integer, pitch2::Integer)::Bool = abs(Int(pitch1)-Int(pitch2)) == 12
 
 #######################################################
 # string name <-> midi pitch
@@ -156,8 +170,8 @@ Return the pitch value of the given note name, which can be of the form
 We define E.g. `name_to_pitch("C4") === 60` (i.e. string
 `"C4"`, representing the middle-C, corresponds to pitch `60`).
 
-See http://newt.phys.unsw.edu.au/jw/notes.html
-and https://en.wikipedia.org/wiki/C_(musical_note) .
+See [http://newt.phys.unsw.edu.au/jw/notes.html](http://newt.phys.unsw.edu.au/jw/notes.html)
+and [https://en.wikipedia.org/wiki/C_(musical_note)](https://en.wikipedia.org/wiki/C_(musical_note)) .
 """
 function name_to_pitch(name)
     pe = collect(Unicode.graphemes(name))
@@ -184,8 +198,8 @@ end
 """
     pitch_to_hz(pitch::Integer, A4::Real = 440) -> hz::Real
 Return the frequency value of the given midi note, optionally given the reference for middle A.
-See https://en.wikipedia.org/wiki/Piano_key_frequencies
-and https://librosa.org/doc/main/_modules/librosa/core/convert.html#midi_to_hz.
+See [https://en.wikipedia.org/wiki/Piano_key_frequencies](https://en.wikipedia.org/wiki/Piano_key_frequencies)
+and [https://librosa.org/doc/main/_modules/librosa/core/convert.html#midi_to_hz](https://librosa.org/doc/main/_modules/librosa/core/convert.html#midi_to_hz).
 """
 function pitch_to_hz(pitch, A4 = 440)
     return A4 * (2^ ((pitch-69) / 12))

diff --git a/test/note.jl b/test/note.jl
@@ -55,3 +55,25 @@ end
     notes[1].pitch = 1
     @test n2[1].pitch ≠ 1
 end
+
+@testset "is octave" begin
+    n1 = Note(name_to_pitch("C4"),0)
+    n2 = Note(name_to_pitch("C5"),1)
+    n3 = Note(name_to_pitch("D5"),2)
+    @test is_octave(n1,n2)
+    @test !is_octave(n1,n3)
+
+    @test is_octave(n1.pitch, name_to_pitch("C5"))
+    @test !is_octave(n1.pitch, name_to_pitch("D5"))
+end
+
+@testset "find max and min" begin
+    n1 = Note(name_to_pitch("C4"),0)
+    n2 = Note(name_to_pitch("C5"),1)
+    n3 = Note(name_to_pitch("D5"),2)
+    notes = Notes([n1,n2,n3])
+    max_pitch, index_max = findmax(n -> n.pitch, notes)
+    @test notes[index_max].pitch == name_to_pitch("D5")
+    min_pitch, index_min = findmin(n -> n.pitch, notes)
+    @test notes[index_min].pitch == name_to_pitch("C4")
+end