Comment by tremon

any reasonable definition of "text" should include musical notation

Then many a dictionary must be unreasonable [0]:

  text
    1. A discourse or composition on which a note or commentary is written;
       the original words of an author, in distinction from a paraphrase, annotation, or commentary.

    6. That part of a document (printed or electronic) comprising the words [..]
  
    7. Any communication composed of words

    n 1. the words of something written

Musical notes do not form words, and therefore are not text. (And no, definition 1 does not refer to musical notes). The written down form of music is called a score, not a text.

[0] e.g. http://dict.org/bin/Dict?Form=Dict2&Database=*&Query=text