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Simplify toRomanNumeral using guards (#3445)

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Alexander Krotov 2017-02-15 02:00:23 +04:00 committed by John MacFarlane
parent 2a3c2b01ea
commit a58112f6bc
1 changed files with 16 additions and 18 deletions
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34
src/Text/Pandoc/Shared.hs
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@ -261,24 +261,22 @@ camelCaseToHyphenated (a:rest) = (toLower a):(camelCaseToHyphenated rest)
-- | Convert number < 4000 to uppercase roman numeral.
toRomanNumeral :: Int -> String
toRomanNumeral x =
if x >= 4000 || x < 0
then "?"
else case x of
_ | x >= 1000 -> "M" ++ toRomanNumeral (x - 1000)
_ | x >= 900 -> "CM" ++ toRomanNumeral (x - 900)
_ | x >= 500 -> "D" ++ toRomanNumeral (x - 500)
_ | x >= 400 -> "CD" ++ toRomanNumeral (x - 400)
_ | x >= 100 -> "C" ++ toRomanNumeral (x - 100)
_ | x >= 90 -> "XC" ++ toRomanNumeral (x - 90)
_ | x >= 50 -> "L" ++ toRomanNumeral (x - 50)
_ | x >= 40 -> "XL" ++ toRomanNumeral (x - 40)
_ | x >= 10 -> "X" ++ toRomanNumeral (x - 10)
_ | x == 9 -> "IX"
_ | x >= 5 -> "V" ++ toRomanNumeral (x - 5)
_ | x == 4 -> "IV"
_ | x >= 1 -> "I" ++ toRomanNumeral (x - 1)
_ -> ""
toRomanNumeral x
| x >= 4000 || x < 0 = "?"
| x >= 1000 = "M" ++ toRomanNumeral (x - 1000)
| x >= 900 = "CM" ++ toRomanNumeral (x - 900)
| x >= 500 = "D" ++ toRomanNumeral (x - 500)
| x >= 400 = "CD" ++ toRomanNumeral (x - 400)
| x >= 100 = "C" ++ toRomanNumeral (x - 100)
| x >= 90 = "XC" ++ toRomanNumeral (x - 90)
| x >= 50 = "L" ++ toRomanNumeral (x - 50)
| x >= 40 = "XL" ++ toRomanNumeral (x - 40)
| x >= 10 = "X" ++ toRomanNumeral (x - 10)
| x == 9 = "IX"
| x >= 5 = "V" ++ toRomanNumeral (x - 5)
| x == 4 = "IV"
| x >= 1 = "I" ++ toRomanNumeral (x - 1)
| otherwise = ""
-- | Escape whitespace and some punctuation characters in URI.
escapeURI :: String -> String