33 lines
776 B
Haskell
33 lines
776 B
Haskell
{- percentages
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-
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- Copyright 2012 Joey Hess <joey@kitenet.net>
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-
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- License: BSD-2-clause
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-}
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module Utility.Percentage (
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Percentage,
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percentage,
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showPercentage
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) where
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import Data.Ratio
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import Utility.HumanNumber
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newtype Percentage = Percentage (Ratio Integer)
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instance Show Percentage where
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show = showPercentage 0
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{- Normally the big number comes first. But 110% is allowed if desired. :) -}
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percentage :: Integer -> Integer -> Percentage
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percentage 0 _ = Percentage 0
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percentage full have = Percentage $ have * 100 % full
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{- Pretty-print a Percentage, with a specified level of precision. -}
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showPercentage :: Int -> Percentage -> String
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showPercentage precision (Percentage p) = v ++ "%"
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where
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v = showImprecise precision n
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n = fromRational p :: Double
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