diff options
Diffstat (limited to 'website/sandbox/chord-drill-sergeant/src/Theory.elm')
| -rw-r--r-- | website/sandbox/chord-drill-sergeant/src/Theory.elm | 399 |
1 files changed, 137 insertions, 262 deletions
diff --git a/website/sandbox/chord-drill-sergeant/src/Theory.elm b/website/sandbox/chord-drill-sergeant/src/Theory.elm index 63cba0e317af..4f89b8c38ffc 100644 --- a/website/sandbox/chord-drill-sergeant/src/Theory.elm +++ b/website/sandbox/chord-drill-sergeant/src/Theory.elm @@ -1,6 +1,7 @@ module Theory exposing (..) import Array exposing (Array) +import Dict exposing (Dict) import List.Extra import Maybe.Extra import Misc @@ -230,11 +231,10 @@ type alias NoteMetadata = } -scaleDegree : Int -> Key -> PitchClass -scaleDegree which { pitchClass } = - case pitchClass of - _ -> - C +{-| An integer representing which note in a given scale to play. +-} +type alias ScaleDegree = + Int {-| Returns the Note in the cental octave of the piano for a given @@ -373,16 +373,16 @@ intervalsForMode mode = in case mode of MajorMode -> - List.map up [ Whole, Whole, Half, Whole, Whole, Whole, Half ] + List.map up [ Whole, Whole, Half, Whole, Whole, Whole ] MinorMode -> - List.map up [ Whole, Half, Whole, Whole, Half, Whole, Whole ] + List.map up [ Whole, Half, Whole, Whole, Half, Whole ] BluesMode -> List.map up [ MinorThird, Whole, Half, Half, MinorThird ] -{-| Return a list of the intervals the comprise a chord. Each interval measures +{-| Return a list of the intervals that a chord. Each interval measures the distance away from the root-note of the chord. -} intervalsForChordType : ChordType -> ChordInversion -> List IntervalVector @@ -648,7 +648,7 @@ notesForChord { note, chordType, chordInversion } = |> Maybe.map (\notes -> note :: notes) -{-| Return the scale for a given `key` +{-| Return the scale for a given `key`. -} notesForKey : Key -> List Note notesForKey { pitchClass, mode } = @@ -718,6 +718,31 @@ allChordTypes = ] +{-| Return a list of all of the key modes about which we know. +-} +allModes : List Mode +allModes = + [ MajorMode, MinorMode, BluesMode ] + + +{-| Return a list of all of the keys about which we know. +-} +allKeys : List Key +allKeys = + allPitchClasses + |> List.Extra.andThen + (\pitchClass -> + allModes + |> List.Extra.andThen + (\mode -> + [ { pitchClass = pitchClass + , mode = mode + } + ] + ) + ) + + {-| Return an array of every note on a piano. Note: Currently this piano has 85 keys, but modern pianos have 88 keys. I would prefer to have 88 keys, but it's not urgent. @@ -832,261 +857,19 @@ notes. -} noteAsNumber : Note -> Int noteAsNumber note = - case note of - C1 -> + let + result = + noteMetadata + |> Array.toList + |> List.indexedMap Tuple.pair + |> Misc.find (\( _, x ) -> x.note == note) + in + case result of + Nothing -> 0 - C_sharp1 -> - 1 - - D1 -> - 2 - - D_sharp1 -> - 3 - - E1 -> - 4 - - F1 -> - 5 - - F_sharp1 -> - 6 - - G1 -> - 7 - - G_sharp1 -> - 8 - - A1 -> - 9 - - A_sharp1 -> - 10 - - B1 -> - 11 - - C2 -> - 12 - - C_sharp2 -> - 13 - - D2 -> - 14 - - D_sharp2 -> - 15 - - E2 -> - 16 - - F2 -> - 17 - - F_sharp2 -> - 18 - - G2 -> - 19 - - G_sharp2 -> - 20 - - A2 -> - 21 - - A_sharp2 -> - 22 - - B2 -> - 23 - - C3 -> - 24 - - C_sharp3 -> - 25 - - D3 -> - 26 - - D_sharp3 -> - 27 - - E3 -> - 28 - - F3 -> - 29 - - F_sharp3 -> - 30 - - G3 -> - 31 - - G_sharp3 -> - 32 - - A3 -> - 33 - - A_sharp3 -> - 34 - - B3 -> - 35 - - C4 -> - 36 - - C_sharp4 -> - 37 - - D4 -> - 38 - - D_sharp4 -> - 39 - - E4 -> - 40 - - F4 -> - 41 - - F_sharp4 -> - 42 - - G4 -> - 43 - - G_sharp4 -> - 44 - - A4 -> - 45 - - A_sharp4 -> - 46 - - B4 -> - 47 - - C5 -> - 48 - - C_sharp5 -> - 49 - - D5 -> - 50 - - D_sharp5 -> - 51 - - E5 -> - 52 - - F5 -> - 53 - - F_sharp5 -> - 54 - - G5 -> - 55 - - G_sharp5 -> - 56 - - A5 -> - 57 - - A_sharp5 -> - 58 - - B5 -> - 59 - - C6 -> - 60 - - C_sharp6 -> - 61 - - D6 -> - 62 - - D_sharp6 -> - 63 - - E6 -> - 64 - - F6 -> - 65 - - F_sharp6 -> - 66 - - G6 -> - 67 - - G_sharp6 -> - 68 - - A6 -> - 69 - - A_sharp6 -> - 70 - - B6 -> - 71 - - C7 -> - 72 - - C_sharp7 -> - 73 - - D7 -> - 74 - - D_sharp7 -> - 75 - - E7 -> - 76 - - F7 -> - 77 - - F_sharp7 -> - 78 - - G7 -> - 79 - - G_sharp7 -> - 80 - - A7 -> - 81 - - A_sharp7 -> - 82 - - B7 -> - 83 - - C8 -> - 84 + Just ( i, _ ) -> + i {-| Return true if all of the notes that comprise `chord` can be played on a @@ -1223,3 +1006,95 @@ viewPitchClass pitchClass = B -> "B" + + +viewMode : Mode -> String +viewMode mode = + case mode of + MajorMode -> + "major" + + MinorMode -> + "minor" + + BluesMode -> + "blues" + + +{-| Return the human-readable format of `key`. +-} +viewKey : Key -> String +viewKey { pitchClass, mode } = + viewPitchClass pitchClass ++ " " ++ viewMode mode + + +{-| Returns a pairing of a scale-degree to the type of chord at that scale +degree. +-} +practiceChordsForMode : Mode -> Dict ScaleDegree ChordType +practiceChordsForMode mode = + case mode of + MajorMode -> + Dict.fromList + [ ( 1, Major ) + , ( 2, Minor ) + , ( 3, Minor ) + , ( 4, Major ) + , ( 5, Major ) + , ( 6, Minor ) + , ( 7, Diminished ) + ] + + MinorMode -> + Dict.fromList + [ ( 1, Minor ) + , ( 2, Diminished ) + , ( 3, Major ) + , ( 4, Minor ) + , ( 5, Minor ) + , ( 6, Major ) + , ( 7, Major ) + ] + + BluesMode -> + Dict.fromList + [ ( 1, MajorDominant7 ) + + -- While many refer to the blues progression as a I-IV-V, the IV + -- chord is really a MajorDominant7 made from the third scale + -- degree. + , ( 3, MajorDominant7 ) + , ( 5, MajorDominant7 ) + ] + + +{-| Returns a list of chords for a particular `key`. +-} +chordsForKey : Key -> List Chord +chordsForKey key = + let + chords = + practiceChordsForMode key.mode + in + notesForKey key + |> List.indexedMap + (\i note -> + case Dict.get (i + 1) chords of + Nothing -> + Nothing + + Just chordType -> + Just + (allInversions + |> List.Extra.andThen + (\inversion -> + [ { note = note + , chordType = chordType + , chordInversion = inversion + } + ] + ) + ) + ) + |> Maybe.Extra.values + |> List.concat |