:: [a] -> [(a, a)]

Consecutive pairs.

>>> pairs [1..10]
[(1,2),(2,3),(3,4),(4,5),(5,6),(6,7),(7,8),(8,9),(9,10)]

>>> pairs []
[]

Run a computation, returning the pair of its output and its result.

runWriter (listen m) = fmap (fst &&& id) (runWriter m)

Extract the key-value pairs from a structure. When you don't need access to the indices in the result, then toList is more flexible in what it accepts.

toList ≡ map snd . itoList

Normalize a sorted list of elements to a range list.

Normalize an arbitrary list of elements to a range list.