I sincerely hope I did not leave in any mistakes. There's quite a lot of testing code, and in places it's quite intricate.

No better review than actual use. :D

quasi blind approval, since you are the expert here :)

That was quick

approved

Excellent

See Suggestion

LC translation

this translation modifies the description

Thanks, I've put it on the list! :]

This one lends itself for a LC translation. (whistling)

No you don't. Don't overthink it, just write a solution which terminates as soon as possible no matter whether the first or second argument is smaller.

ouch, what, really? This is pretty nuts. Do I somehow need a foldr solution?

In tests import Ch02.Beside became import Ch02.Beside (beside, besideN)

Note about ∞ added, thanks.

Note about infinity added, thanks.

Thanks, reasonable. (x - y) replaced with |x - y| and many shown as ∞.