Totally agree, what we often see nowadays is still interesting, but mostly a "rich text comment" style. The two main factors for this are that such preprocessor

Totally agree, what we often see nowadays is still interesting, but mostly a "rich text comment" style. The two main factors for this are that such preprocessors are easier to write than weave/tangle systems, and that many people feel that in a modern idiom this isn't needed anyway. Shorter functions, no need for pre-declared variables, function hoisting, less global state... Not that this is totally wrong, working around the limitations of Pascal/C is one reason for the way Knuth's literate programming style was developed. The way I see it, the more simpler style is pretty good for a well-documented program that needs to be maintained, less so for a narrative that is a bit less focused, documenting the way something was initially written ("Let's add another field to our wibble_wobble structure to make wonk-gibbling work properly").