It's not Knuth's job to write efficient word-sorting programs. That job is long done and now it's nobody's job (unless one can do better than existing tools, bu

It's not Knuth's job to write efficient word-sorting programs. That job is long done and now it's nobody's job (unless one can do better than existing tools, but that wasn't Knuth goal either). His job was to demonstrate how you do literate programming, which is completely different. If I needed to demo how to program certain algorithm so that I could explain it to students, I'd write one code, if I needed absolutely fastest possible tool, I'd write another code (probably in C or some asm even). Different tasks - different approaches.