Think of a formula film or TV show. Eco looks at the standard James Bond Plot. The films which did not adhere to this syntagm were not successful. Wherever there is a choice to be made, a text is defined as much by its exclusions as its inclusions. Each media text exists in context and relationship to others.
Genres are formal conventions for certain types of text.
These are most apparent in parody versions. Sometimes crime fiction harks back to themes present in myths and legends. This is part of the way in which culture is used to explore ethical issues. It is the reader who creates most of the text After a long wait, the detective finally entered the cell. Robertson was adamant that he would tell the police nothing, but as he sat in that uncomfortable metal chair, his resolve wavered.