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{-# LANGUAGE OverloadedStrings,FlexibleContexts #-}
module Logstat.Value where
import Control.Monad.Except
import qualified Data.Attoparsec.ByteString.Char8 as A
import qualified Data.ByteString as B
import qualified Data.ByteString.Char8 as B8
import Logstat.Types
asBool :: Val -> Bool
asBool (Val b _) = b /= "" && b /= "0"
asBS :: Val -> B.ByteString
asBS (Val b _) = b
asNum :: MonadError EvalError m => Val -> m Double
asNum (Val b n) = maybe (throwError $ Loc Nothing $ InvalidNumber b) return n
-- Constructors are strict in their arguments
bool :: Bool -> Val
bool True = bs "1"
bool False = bs ""
bs :: B.ByteString -> Val
bs s = s `seq` Val s (parseNum s)
num :: Double -> Val
num n = n `seq` Val (fmtNum n) (Just n)
fmtNum :: Double -> B.ByteString
fmtNum v = let v' = B8.pack (show v) in maybe v' id $ B.stripSuffix ".0" v'
parseNum :: B.ByteString -> Maybe Double
parseNum = either (const Nothing) Just . A.parseOnly (A.double <* A.endOfInput)
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