Environment:      Siren
Superclass:         Object
Category:         Music-PitchClasses
Instance variables:   sharps flats

Notion of signature is related to the notion of "legal" scales, i.e.
scales having only sharps OR flats in their signature.
So method tonality here works only for legal scales.
It should possible to compute the tonality for arbitrary scales though,
but I am not sure how

printing

printOn: s
   

storeOn: s
   

testing

flatsInRightOrder
   

isEmpty
   

isLegal
   

sharpsInRightOrder
   

tonality

tonality
   

access

alterate: aNaturalNote
   

flats
   

initialize
   

nbFlats: n
   

nbSharps: n
   

reOrderSharpsAndFlats
   attempts to reorder flats and sharps according to the natural order as found in
   PitchClass

sharps
   

sharps: s flats: f
   attempts to reorder flats and sharps according to the natural order as found in
   PitchClass

MetaClass:         Signature class

examples

example
   

example2
   Signature new tonality -> C MajorScale
   (Signature new nbSharps: 4) tonality -> E MajorScale   
   (Signature new nbFlats: 3) tonality -> Eb MajorScale

example3
      Signature fromTonality: N D majorScale
   Signature fromTonality: N E flat majorScale

example4
   Signatures may be created for illegal scales. However, method
   tonality yields an error for these scales:
   
   Signature fromTonality: N D minorScale -> 1 sharps; 1 flats
   Signature sharps: (Array with: N F sharp) flats: (Array with: (N E flat)) -> 1 sharps; 1 flats
   (Signature fromTonality: N D minorScale) tonality -> error

creation

choseSignature
   Signature choseSignature

fromTonality: aScale
   Signature fromTonality: N E flat majorScale

new
   

sharps: s flats: f