FA-81283 / Music interval and transposition theory / Member archive

Staff position and ledger lines for a clef: altered notes cannot be placed · case 03

C#4 or Bb3 are rejected as malformed even though accidentals do not change staff position.

Member previewVariant 3 · 3 implementations · 8 checks per implementation

Case contract

Input [note, clef] where note is a letter, accidentals (# b x, ignored for placement) and a nonnegative octave, and clef is treble (bottom line E4), bass (G2), alto (F3) or tenor (D3). Position counts diatonic steps above the bottom line (lines are even positions 0..8). Ledger lines: below the staff (-position)//2 for negative positions, above (position-8)//2 for positions over 8, else 0. Return [position, ledgers] or None when invalid.

Why this case matters

Engraving and notation-rendering code places noteheads and ledger lines from pitch spellings.

One recorded failure

Sample boundary fixture

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

Boundary fixture	Actual	Expected	Outcome
oracle 3	`null`	`[-2, 1]`	Failed

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