FA-81178 / Music interval and transposition theory / Member archive

Chord symbol to pitch classes: chord tones above B not wrapped · case 03

An A major triad returns [9,13,16] instead of [9,1,4].

Member previewVariant 3 · 3 implementations · 8 checks per implementation

Case contract

Input a chord symbol: root letter with optional # or b, a quality from "", m, dim, aug, 7, maj7, m7, m7b5, dim7, sus4, mMaj7, 6, and optionally "/" plus a bass note (letter with optional # or b and nothing else). Return pitch classes root-first in template order; for a slash chord the bass moves to the front (removed from its old position if it is a chord tone, otherwise added). Unknown or malformed symbols return None.

Why this case matters

Lead-sheet, accompaniment and guitar-chart tools expand chord symbols into voicings.

One recorded failure

Sample boundary fixture

This sample comes from the broken implementation of a controlled reproducer.

Boundary fixture	Actual	Expected	Outcome
oracle 0	`[10, 14, 17, 20]`	`[10, 2, 5, 8]`	Failed

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