String.hs

{-# LANGUAGE CPP #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE TypeSynonymInstances #-}
{-# LANGUAGE OverloadedStrings #-}
-----------------------------------------------------------------------------
-- |
-- Module      :  Miso.String
-- Copyright   :  (C) 2016-2018 David M. Johnson
-- License     :  BSD3-style (see the file LICENSE)
-- Maintainer  :  David M. Johnson <djohnson.m@gmail.com>
-- Stability   :  experimental
-- Portability :  non-portable
----------------------------------------------------------------------------
module Miso.String
  ( ToMisoString (..)
  , FromMisoString (..)
  , fromMisoString
  , MisoString
  , module Data.Monoid
  , module Data.Text
  , ms
  ) where

import qualified Data.ByteString         as B
import qualified Data.ByteString.Lazy    as BL
import           Data.Monoid
import           Data.JSString
import           Data.JSString.Text
import           Data.Text
import qualified Data.Text               as T
import qualified Data.Text.Encoding      as T
import qualified Data.Text.Lazy          as LT
import qualified Data.Text.Lazy.Encoding as LT
import           Text.Read(readEither)


-- | String type swappable based on compiler
type MisoString = Text

-- | Convenience class for creating `MisoString` from other string-like types
class ToMisoString str where
  toMisoString :: str -> MisoString

-- | Class from safely parsing 'MisoString'
class FromMisoString t where
  -- -- | Parses a `MisoString`
  fromMisoStringEither :: MisoString -> Either String t

-- | Parses a `MisoString`, throws an error when decoding
-- fails. Use `fromMisoStringEither` for as a safe alternative.
fromMisoString :: FromMisoString a => MisoString -> a
fromMisoString s = case fromMisoStringEither s of
                     Left err -> error err
                     Right x  -> x

-- | Convenience function, shorthand for `toMisoString`
ms :: ToMisoString str => str -> MisoString
ms = toMisoString

instance ToMisoString MisoString where
  toMisoString = id
instance ToMisoString String where
  toMisoString = T.pack
instance ToMisoString LT.Text where
  toMisoString = LT.toStrict
instance ToMisoString JSString where
  toMisoString = textFromJSString
instance ToMisoString B.ByteString where
  toMisoString = toMisoString . T.decodeUtf8
instance ToMisoString BL.ByteString where
  toMisoString = toMisoString . LT.decodeUtf8
instance ToMisoString Float where
  toMisoString = T.pack . show
instance ToMisoString Double where
  toMisoString = T.pack . show
instance ToMisoString Int where
  toMisoString = T.pack . show
instance ToMisoString Word where
  toMisoString = T.pack . show

instance FromMisoString MisoString where
  fromMisoStringEither = Right
instance FromMisoString String where
  fromMisoStringEither = Right . T.unpack
instance FromMisoString LT.Text where
  fromMisoStringEither = Right . LT.fromStrict
instance FromMisoString JSString where
  fromMisoStringEither = Right . textToJSString
instance FromMisoString B.ByteString where
  fromMisoStringEither = fmap T.encodeUtf8 . fromMisoStringEither
instance FromMisoString BL.ByteString where
  fromMisoStringEither = fmap LT.encodeUtf8 . fromMisoStringEither
instance FromMisoString Float where
  fromMisoStringEither = readEither . T.unpack
instance FromMisoString Double where
  fromMisoStringEither = readEither . T.unpack
instance FromMisoString Int where
  fromMisoStringEither = readEither . T.unpack
instance FromMisoString Word where
  fromMisoStringEither = readEither . T.unpack