Fretboard & Tab Integrity

Fretboard & Tab Integrity Standards

Use this skill when modifying TabAnalysisService, TabToPitchConverter, or Fretboard logic.

1. Canonical Representation

Single Source of Truth for Pitch.

• Rule: Always convert Tab (String/Fret) -> MidiNote (Abs integer) -> PitchClass (0-11 integer) immediately.
• Anti-Pattern: Passing around string names like "A#" or "Bb" in the analysis pipeline.
• Verification: Analysis classes should take int or PitchClass inputs, never string.

2. Coordinate Safety

Validate Physical Possibility.

• Rule: All Fret coordinates must be bounded (0 to Skipped to MaxFret).
• Rule: All String indices must check against Instrument.StringCount.
• Validation:

  if (fret < 0 && fret != -1) throw new InvalidFretException();
  if (stringIndex >= tuning.Strings.Count) throw new InvalidStringException();
  

3. Bass & Inversion Awareness

The Lowest Note Matters.

• Rule: When identifying chords from Tab, the lowest pitch (by Frequency/MidiValue) is the Bass.
• Rule: IdentifyChord must accepts an explicit BassPitchClass.
• Rule: Naming logic MUST append slash (e.g., "/E") if Root != Bass.

4. Tab Protocol

Defensive Parsing.

• Rule: Support variable string counts (4-string Bass vs 6-string Guitar vs 7-string). Don't hardcode "6".
• Rule: Handle "Ghost Notes" (x), "Ties", and "Rests" explicitly.
• Rule: All Tab Parsing tests must include a "Bad Input" case (e.g., misaligned bars, invalid chars).

5. Golden Set Validation

Regression Testing.

• Rule: Key musical pattern tests (like the Andalusian Cadence) are immutable.
• Rule: When refactoring detection logic, you MUST run the RefactoringImplementationTests suite.