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|
{- numbers for humans
-
- Copyright 2012-2021 Joey Hess <id@joeyh.name>
-
- License: BSD-2-clause
-}
module Utility.HumanNumber (showImprecise) where
{- Displays a fractional value as a string with a limited number
- of decimal digits. -}
showImprecise :: RealFrac a => Int -> a -> String
showImprecise precision n
| precision == 0 || remainder' == 0 = show (round n :: Integer)
| otherwise = show int' ++ "." ++ striptrailing0s (pad0s $ show remainder')
where
int :: Integer
(int, frac) = properFraction n
remainder = round (frac * 10 ^ precision) :: Integer
(int', remainder')
-- carry the 1
| remainder == 10 ^ precision = (int + 1, 0)
| otherwise = (int, remainder)
pad0s s = replicate (precision - length s) '0' ++ s
striptrailing0s = reverse . dropWhile (== '0') . reverse
|
