Several programming systems for computer music are based upon the data-flow family of programming paradigms. In the first part of this article, we shall introduce the general features and lexicon of data-flow programming, and review some specific instances of it with specific reference to computer music applications. We shall then move the discussion to Max's very peculiar take on data-flow, and evaluate its motivation and shortcomings. Subsequently, we shall show how the bach library can support different programming styles within Max, improving the expression, the readability and the maintenance of complex algorithms. In particular, the latest version of bach has introduced bell , a small textual programming language embedded in Max and specifically designed to facilitate programming tasks related to manipulation of symbolic musical material.