Ironically, I think the examples given in the post validate Dijkstra’s points, instead of disproving them, as the author intended.

How so?

I'm struggling to see how Roger's manipulation of the expressions without executing each line validates Dijkstra's point...

	▲	empath75 3 hours ago \| parent [-]
		"This is easy to understand, see:" 5 lines of completely inscrutable symbols follow. If you are expecting someone to learn a completely new notational language before you can communicate a basic algorithm, you have gone wrong somewhere. You could also similarly write down merge sort in pure lambda calculus, which is interesting as an exercise, but not especially useful as working code, or as a way to explain how merge sort works.