64 lines
2.9 KiB
Haskell
64 lines
2.9 KiB
Haskell
module Handler.Utils.I18n
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( i18nWidgetFile
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, i18nWidgetFiles
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, module Utils.I18n
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) where
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import Import.NoFoundation
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import Foundation.Type
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import Utils.I18n
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import Language.Haskell.TH
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import Language.Haskell.TH.Syntax (qRunIO)
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import qualified Data.List as List
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import qualified Data.List.NonEmpty as NonEmpty
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import qualified Data.Map as Map
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import System.Directory (listDirectory)
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-- | Add language dependent template files
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--
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-- For large files which are translated as a whole.
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--
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-- Argument musst be a directory under @/templates@,
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-- which contains a file for each language,
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-- eg. @imprint@ for choosing between
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-- @/templates/imprint/de.hamlet@, @/templates/imprint/de-at.hamlet@,
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-- and @/templates/imprint/en.hamlet@
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--
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-- Dependency detection cannot work properly (no `addDependentFile`-equivalent
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-- for directories)
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-- @$ stack clean@ is required so new translations show up
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i18nWidgetFile :: FilePath -> Q Exp
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i18nWidgetFile basename = do
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-- Construct list of available translations (@de@, @en@, ...) at compile time
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let i18nDirectory = "templates" </> "i18n" </> basename
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availableFiles <- qRunIO $ listDirectory i18nDirectory
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let availableTranslations = sortWith (NTop . flip List.elemIndex (NonEmpty.toList appLanguages)) . List.nub $ pack . takeBaseName <$> availableFiles
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availableTranslations' <- maybe (fail $ "‘" <> i18nDirectory <> "’ is empty") return $ NonEmpty.nonEmpty availableTranslations
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-- Dispatch to correct language (depending on user settings via `selectLanguage`) at run time
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ws <- newName "ws" -- Name for dispatch function
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letE
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[ funD ws $ [ clause [litP $ stringL l] (normalB . widgetFile $ "i18n" </> basename </> l) []
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| l <- unpack <$> NonEmpty.toList availableTranslations' -- One function definition for every available language
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] ++ [ clause [wildP] (normalB [e| error "selectLanguage returned an invalid translation" |]) [] ] -- Fallback mostly there so compiler does not complain about non-exhaustive pattern match
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] [e|selectLanguage availableTranslations' >>= $(varE ws)|]
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i18nWidgetFiles :: FilePath -> Q Exp
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i18nWidgetFiles basename = do
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availableTranslations' <- i18nWidgetFilesAvailable' basename
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-- Dispatch to correct language (depending on user settings via `selectLanguage`) at run time
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ws <- newName "ws" -- Name for dispatch function
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letE
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[ funD ws $ [ clause [litP $ stringL kind, litP $ stringL l] (normalB [e|$(widgetFile $ "i18n" </> basename </> kind <.> l) :: WidgetFor UniWorX ()|]) []
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| (unpack -> kind, ls) <- Map.toList availableTranslations'
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, l <- unpack <$> NonEmpty.toList ls
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] ++ [ clause [wildP, wildP] (normalB [e| error "selectLanguage returned an invalid translation" |]) [] ] -- Fallback mostly there so compiler does not complain about non-exhaustive pattern match
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] [e|imap (\kind ls -> selectLanguage ls >>= $(varE ws) kind) availableTranslations'|]
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