I would like to define a major mode for some class of documents, a few faces, and fontification rules that find fragments users would want colored and apply those faces. The user will be able to customize the faces to their liking.
As a use case, users could colour cells in a table as they wish. When they load the file again, the colours would persist.
How would a basic major-mode with specific faces that would colour cells in a table look like?
