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Diffstat (limited to 'Utility/Percentage.hs')
| -rw-r--r-- | Utility/Percentage.hs | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/Utility/Percentage.hs b/Utility/Percentage.hs new file mode 100644 index 0000000..a30c260 --- /dev/null +++ b/Utility/Percentage.hs @@ -0,0 +1,33 @@ +{- percentages + - + - Copyright 2012 Joey Hess <id@joeyh.name> + - + - License: BSD-2-clause + -} + +module Utility.Percentage ( + Percentage, + percentage, + showPercentage +) where + +import Data.Ratio + +import Utility.HumanNumber + +newtype Percentage = Percentage (Ratio Integer) + +instance Show Percentage where + show = showPercentage 0 + +{- Normally the big number comes first. But 110% is allowed if desired. :) -} +percentage :: Integer -> Integer -> Percentage +percentage 0 _ = Percentage 0 +percentage full have = Percentage $ have * 100 % full + +{- Pretty-print a Percentage, with a specified level of precision. -} +showPercentage :: Int -> Percentage -> String +showPercentage precision (Percentage p) = v ++ "%" + where + v = showImprecise precision n + n = fromRational p :: Double |