I think you can generalize this problem to just about any subject, or any kind of story telling. e.g. Herodotus' Histories has these digressions (I've sometimes

I think you can generalize this problem to just about any subject, or any kind of story telling. e.g. Herodotus' Histories has these digressions (I've sometimes seen them called 'pendants', which I really like), which can also be nested. i.e. time is not mapped linearly to the text, the text jumps around in time (and space) to provide context to the main narrative (and sometimes to provide context to the context). Digressions also appear in Homer. So you can think of the story elements as a kind of graph that have to be flattened into a linear structure, and to perform this flattening well is the art of good story-telling.