Text.I18n.Po

Internationalization support for Haskell based on GNU gettext (http://www.gnu.org/software/gettext). This module contains PO parser. PO files are assumed to be in UTF-8 encoding.

Plural forms are not yet implemented.

Text.I18n and Control.Monad.Trans are exported for convenience.

Use System.IO.UTF8 whenever you need to output a localized string.

Type Declarations

newtype Msgid

Constructors

Msgid String

Instances

Eq Msgid

Ord Msgid

Show Msgid

type Msgstr = String

data L10nMode

Localization mode. L10nMust will throw an exception if unable to translate whereas L10nMay will just return the original Msgid String. L10nMay is used by localize.

Constructors

L10nMust

L10nMay

newtype Locale

Constructors

Locale String

Instances

Eq Locale

Ord Locale

Show Locale

type Context = String

type I18n a = ReaderT (Locale, L10n, L10nMode, Maybe Context) IO a

The Internationalization monad allows the use of IO through liftIO.

type L10n = Map Locale (Map (Maybe Context) (Map Msgid [Msgstr]))

The Localization structure.

PO parsing

getL10n

Arguments

:: FilePath

Directory containing PO files.

-> IO (L10n, [ParseError])

Localization structure and a list of parse errors.

Builds L10n structure by parsing .po files contained in a given directory. L10n structure is to be passed to localize function. L10n structure is used internaly by the I18n monad.

I18n Monad Functions

localize

Arguments

:: L10n

Structure containing localization data

-> Locale

Locale to use

-> I18n a

Inernationalized action

-> IO a

Localized action

The top level localization function.

 import Text.I18n.Po
 import qualified System.IO.UTF8 as Utf8

 main = do
   (l10n,errors) <- getL10n "dir/to/po"
   localize l10n (Locale "en") impl

gettext :: PrintfType a => String -> I18n a

The heart of I18n monad. Based on Text.Printf.printf.

 impl = do
       hello <- gettext "Hello, %s!"
       liftIO (Utf8.putStrLn (hello "Joe"))

withContext

Arguments

:: Maybe Context

Context to use

-> I18n a

Internationalized action

-> I18n a

New internationalized action

Sets a local Context for an internationalized action. If there is no translation, then no context version is tried.

 impl2 = withContext (Just "test") impl

withLocale

Arguments

:: Locale

Locale to use

-> I18n a

Internationalized action

-> I18n a

New internationalized action. Note: while this action is localy localized already, it is to be a part of another internationalized action. Therefore the final type is internationalized.

Sets a local Locale for an internationalized action.

 impl3 = withLocale (Locale "ru") impl2

localize'

Arguments

:: L10n

Structure containing localization data

-> L10nMode

Localization mode

-> Locale

Locale to use

-> I18n a

Inernationalized action

-> IO a

Localized action

The top level localization function with a mode parameter.

 main2 = localize' (Text.I18n.Po.getL10n "dir/to/po")
                   L10nMust
                   (Locale "en")
                   impl

module Control.Monad.Trans