59 lines
1.5 KiB
Haskell
59 lines
1.5 KiB
Haskell
{-# LANGUAGE TypeSynonymInstances #-}
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{-# LANGUAGE FlexibleInstances #-}
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{-# LANGUAGE UndecidableInstances #-}
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{-# LANGUAGE OverlappingInstances #-}
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---------------------------------------------------------
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--
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-- Module : Web.Restful.I18N
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-- Copyright : Michael Snoyman
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-- License : BSD3
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--
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-- Maintainer : Michael Snoyman <michael@snoyman.com>
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-- Stability : Stable
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-- Portability : portable
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--
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-- Simple method for internationalization.
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--
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---------------------------------------------------------
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module Web.Restful.I18N
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( Language
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, Translator
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, I18N (..)
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, toTranslator
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) where
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import qualified Data.ByteString.Lazy as B
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import qualified Data.ByteString as BS
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import Data.ByteString.Class
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type Language = String
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type Translator = [Language] -> B.ByteString
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class I18N a where
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translate :: a -> Translator
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instance I18NString a => I18N a where
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translate a langs = toLazyByteString $ helper langs where
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helper [] = defTrans a
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helper (l:ls) =
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case tryTranslate a l of
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Nothing -> helper ls
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Just s -> s
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class I18NString a where
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defTrans :: a -> String
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tryTranslate :: a -> Language -> Maybe String
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toTranslator :: LazyByteString lbs => lbs -> Translator
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toTranslator = translate . toLazyByteString
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instance I18N B.ByteString where
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translate = const
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instance I18N BS.ByteString where
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translate bs _ = toLazyByteString bs
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instance I18NString String where
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defTrans = id
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tryTranslate = const . Just
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