Libmusic is an iOS open-source library for music elements such as Notes, Scales, Chord, and instruments Chord Views ( currently only Piano is supported ), its meant to be used as a framework to work with music elements, its the abstraction you needed for music elements, notations and characteristics for iOS.
Libmusic by Victor Lima is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License.
Based on a work at github.com.
Concrete Solutions (http://www.concretesolutions.com.br) team for feedback, specially Dhiana Deva (for the RegEx insight =)), and Victor Oliveira for all the conversations. My musicians friends: Fabio Ribeiro, Edu Serra, Juarez Escostegui, João Rios Cotta, Daniela Lima and all others who gave me feedback while developing it, during the problem/solution interviews.