The basic counter-example I was thinking of is Mathematica. In Mathematica you can paste an image as input, and have the input embedded into the document and us

The basic counter-example I was thinking of is Mathematica. In Mathematica you can paste an image as input, and have the input embedded into the document and used as an operator. Similarly you could imagine files/documents/etc be represented as elements of rich text. This is _not_ an easy problem however! As an example, if I had a document referring to `~/.emacs`, it could be: - the path on the system of the author's machine - the path on the system of the reader's machine - the content of the file on the author's machine - the content of the file on the reader's machine - A sort of lisp data structure based on the content of the file on (author or reader's machine) Basically you enter in to the "reference or value" problem on many things. Text doesn't have this problem because it has no solution to the value problem, for the most part, apart from like embedding a base64 blob into your text. But hey, if you're building an entire OS anyways, and you have some rich text primitives, you could imagine having that in the base libraries and setting up some COM-like primitives all over and work from there. I mean this is basically Word, at this point. But a programmer-y version of Word would be interesting from my perspective.