Can't speak to graduate student experiences, but I did take Dr. Harper's principles of programming languages class as an undergrad.
The course was ambitious and moved at a breakneck pace, and Dr. Harper could be a whirlwind in lecture. As some of the anecdotes mention, he's pretty opinionated. He'd often go on intense (albeit well-informed), tangential rants, particularly about Python.
Personally, I would have preferred a less comprehensive course with more time to let some of the abstract ideas settle, but I can imagine his attitude and approach being well-suited to energetic graduate advising.
For those curious about the material, we covered a significant portion of his Practical Foundations of Programming Languages book: https://www.cs.cmu.edu/~rwh/pfpl/2nded.pdf
The course was ambitious and moved at a breakneck pace, and Dr. Harper could be a whirlwind in lecture. As some of the anecdotes mention, he's pretty opinionated. He'd often go on intense (albeit well-informed), tangential rants, particularly about Python.
Personally, I would have preferred a less comprehensive course with more time to let some of the abstract ideas settle, but I can imagine his attitude and approach being well-suited to energetic graduate advising.
For those curious about the material, we covered a significant portion of his Practical Foundations of Programming Languages book: https://www.cs.cmu.edu/~rwh/pfpl/2nded.pdf