devforms-0.2.0.1: src/ParsedInteger.hs

module ParsedInteger (ParsedInteger, parseWithBounds, parsedToInteger, IntegerBoundError (..))
where

newtype ParsedInteger = ParsedInteger Integer

data IntegerBoundError = IntegerOutOfBounds deriving (Show)

parseWithBounds :: Maybe Integer -> Maybe Integer -> Integer -> Either IntegerBoundError ParsedInteger
parseWithBounds (Just lowerBoundInclusive) (Just upperBoundInclusive) n =
    if lowerBoundInclusive <= n && upperBoundInclusive >= n
        then pure $ ParsedInteger n
        else Left IntegerOutOfBounds
parseWithBounds (Just lowerBoundInclusive) Nothing n =
    if lowerBoundInclusive <= n
        then pure $ ParsedInteger n
        else Left IntegerOutOfBounds
parseWithBounds Nothing (Just upperBoundInclusive) n =
    if upperBoundInclusive >= n
        then pure $ ParsedInteger n
        else Left IntegerOutOfBounds
parseWithBounds Nothing Nothing n = Right $ ParsedInteger n

parsedToInteger :: ParsedInteger -> Integer
parsedToInteger (ParsedInteger n) = n