utility-ht-0.0.7: Various small helper functions for Lists, Maybes, Tuples, Functions

Data.List.Match

Synopsis

Documentation

take :: [b] -> [a] -> [a]

Make a list as long as another one

drop :: [b] -> [a] -> [a]

Drop as many elements as the first list is long

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

replicate :: [a] -> b -> [b]

compareLength :: [a] -> [b] -> Ordering

Compare the length of two lists over different types. It is equivalent to (compare (length xs) (length ys)) but more efficient.

lessOrEqualLength :: [a] -> [b] -> Bool

lessOrEqualLength x y is almost the same as compareLength x y <= EQ, but lessOrEqualLength [] undefined = True, whereas compareLength [] undefined <= EQ = undefined.

shorterList :: [a] -> [a] -> [a]

Returns the shorter one of two lists. It works also for infinite lists as much as possible. E.g. shortList (shorterList (repeat 1) (repeat 2)) [1,2,3] can be computed. The trick is, that the skeleton of the resulting list is constructed using zipWith without touching the elements. The contents is then computed (only) if requested.