What's wrong
Mode.Ionian is an alias that returns Major, whose Name is "major", and ModeTests asserts Mode.Major == Mode.Ionian. But Mode.TryParse (Semantics.Music/Mode.cs:178) builds new() { Name = name.ToLowerInvariant() }, so parsing "ionian" gives a mode whose Name is "ionian". Record equality compares Name, so the parsed value is not equal to Mode.Ionian or Mode.Major.
Code that branches on key.Mode == Mode.Major then treats a parsed Ionian key as minor. For example, Semantics.Music/Progression.Chromatic.cs lines 55 and 68 pick the secondary-dominant table and the parallel mode this way.
Repro
Mode.Parse("ionian") == Mode.Ionian; // False
Key ionian = Key.Parse("C ionian");
ionian == Key.Create(PitchClass.Create(0), Mode.Major); // False
Progression.Parse("4/4 C D7 G C").ChromaticChords(ionian)[0].Detail; // "V/v" (with Mode.Major: "V/V")
Progression.Parse("4/4 C Fm C").ChromaticChords(ionian)[0]; // Chromatic, Detail = null
// (with Mode.Major: borrowed "from parallel minor")This was reproduced with a temporary MSTest on net10.0 at 8c06aba.
Why it matters
"C ionian" and "C major" are the same key, and the static API already says they are equal. Analysis that goes through Parse gives different results depending on which spelling the user typed. Keys parsed from the same text also don't compare equal to keys built in code.
Suggested fix / acceptance criteria
- Canonicalize aliases in
TryParse, for example with a small alias table mapping "ionian" to "major". Check the other alias properties on Mode too, such as Aeolian versus Minor, if any exist.
Assert.AreEqual(Mode.Ionian, Mode.Parse("ionian")) and Assert.AreEqual(Key.Parse("C major"), Key.Parse("C ionian")) pass.
What's wrong
Mode.Ionianis an alias that returnsMajor, whoseNameis"major", andModeTestsassertsMode.Major == Mode.Ionian. ButMode.TryParse(Semantics.Music/Mode.cs:178) buildsnew() { Name = name.ToLowerInvariant() }, so parsing "ionian" gives a mode whoseNameis"ionian". Record equality comparesName, so the parsed value is not equal toMode.IonianorMode.Major.Code that branches on
key.Mode == Mode.Majorthen treats a parsed Ionian key as minor. For example,Semantics.Music/Progression.Chromatic.cslines 55 and 68 pick the secondary-dominant table and the parallel mode this way.Repro
This was reproduced with a temporary MSTest on net10.0 at 8c06aba.
Why it matters
"C ionian" and "C major" are the same key, and the static API already says they are equal. Analysis that goes through
Parsegives different results depending on which spelling the user typed. Keys parsed from the same text also don't compare equal to keys built in code.Suggested fix / acceptance criteria
TryParse, for example with a small alias table mapping"ionian"to"major". Check the other alias properties onModetoo, such asAeolianversusMinor, if any exist.Assert.AreEqual(Mode.Ionian, Mode.Parse("ionian"))andAssert.AreEqual(Key.Parse("C major"), Key.Parse("C ionian"))pass.