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module Common ((?), (?:), fromDigits, leftPad, listToProse, asOrdinal, showDayOfWeek, showMonth) where
import Data.List (replicate, take)
import Data.List.NonEmpty (NonEmpty ((:|)))
import Data.Maybe (fromMaybe)
import Intro
fromDigits :: [Int] -> Int
fromDigits = foldl (\n d -> 10 * n + d) 0
leftPad :: Int -> a -> [a] -> [a]
leftPad m x xs = replicate (m - length ys) x ++ ys
where
ys = take m xs
(?) :: Bool -> a -> a -> a
(?) True x _ = x
(?) False _ y = y
infixr 1 ?
(?:) :: Maybe a -> a -> a
maybeA ?: b = fromMaybe b maybeA
infixr 0 ?:
listToProse :: NonEmpty String -> String
listToProse (x :| xs) = mconcat . reverse $ proseJoin xs [x]
where
proseJoin [] ys = ys
proseJoin [y] [] = [y]
proseJoin [y] zs = y : " and " : zs
proseJoin (y : ys) zs = proseJoin ys (y : ", " : zs)
asOrdinal :: Int -> String
asOrdinal 11 = "11th"
asOrdinal 12 = "12th"
asOrdinal 13 = "13th"
asOrdinal n =
show n ++ case n `mod` 10 of
1 -> "st"
2 -> "nd"
3 -> "rd"
_ -> "th"
showDayOfWeek :: Int -> Maybe String
showDayOfWeek = \case
0 -> Just "Sunday"
1 -> Just "Monday"
2 -> Just "Tuesday"
3 -> Just "Wednesday"
4 -> Just "Thursday"
5 -> Just "Friday"
6 -> Just "Saturday"
_ -> Nothing
showMonth :: Int -> Maybe String
showMonth = \case
1 -> Just "January"
2 -> Just "February"
3 -> Just "March"
4 -> Just "April"
5 -> Just "May"
6 -> Just "June"
7 -> Just "July"
8 -> Just "August"
9 -> Just "September"
10 -> Just "October"
11 -> Just "November"
12 -> Just "December"
_ -> Nothing
|
