Moved BCP47 specific functions from Writers.Shared to new module.

Text.Pandoc.BCP47 (unexported, internal module).
`getLang`, `Lang(..)`, `parseBCP47`.

6 files changed, 126 insertions, 87 deletions

diff --git a/pandoc.cabal b/pandoc.cabal
index 3b644c7d0..5ae255284 100644
--- a/pandoc.cabal
+++ b/pandoc.cabal
@@ -463,6 +463,7 @@ Library
                    Text.Pandoc.Lua.Util,
                    Text.Pandoc.CSS,
                    Text.Pandoc.UUID,
+                   Text.Pandoc.BCP47
                    Text.Pandoc.Slides,
                    Text.Pandoc.Compat.Time,
                    Paths_pandoc
diff --git a/src/Text/Pandoc/BCP47.hs b/src/Text/Pandoc/BCP47.hs
new file mode 100644
index 000000000..ae7f54473
--- /dev/null
+++ b/src/Text/Pandoc/BCP47.hs
@@ -0,0 +1,117 @@
+{-
+Copyright (C) 2017 John MacFarlane <jgm@berkeley.edu>
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program; if not, write to the Free Software
+Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+-}
+
+{- |
+   Module      : Text.Pandoc.BCP47
+   Copyright   : Copyright (C) 2017 John MacFarlane
+   License     : GNU GPL, version 2 or above
+
+   Maintainer  : John MacFarlane <jgm@berkeley.edu>
+   Stability   : alpha
+   Portability : portable
+
+Functions for parsing and rendering BCP47 language identifiers.
+-}
+module Text.Pandoc.BCP47 (
+                       getLang
+                     , parseBCP47
+                     , Lang(..)
+                     , renderLang
+                     )
+where
+import Control.Monad (guard)
+import Data.Char (isAscii, isLetter, isUpper, isLower)
+import Data.List (intercalate)
+import Text.Pandoc.Definition
+import Text.Pandoc.Class (PandocMonad, report)
+import Text.Pandoc.Logging
+import Text.Pandoc.Options
+import qualified Text.Parsec as P
+
+-- | Represents BCP 47 language/country code.
+data Lang = Lang{ langLanguage   :: String
+                , langScript     :: String
+                , langRegion     :: String
+                , langVariants   :: [String] }
+                deriving (Eq, Ord, Show)
+
+-- | Render a Lang as BCP 47.
+renderLang :: Lang -> String
+renderLang lang = intercalate "-" (langLanguage lang : filter (not . null)
+                    ([langScript lang, langRegion lang] ++ langVariants lang))
+
+-- | Get the contents of the `lang` metadata field or variable.
+getLang :: PandocMonad m => WriterOptions -> Meta -> m (Maybe Lang)
+getLang opts meta = case
+  (case lookup "lang" (writerVariables opts) of
+        Just s -> Just s
+        _      ->
+          case lookupMeta "lang" meta of
+               Just (MetaInlines [Str s]) -> Just s
+               Just (MetaString s)        -> Just s
+               _                          -> Nothing) of
+       Nothing -> return Nothing
+       Just s  -> case parseBCP47 s of
+                       Left _ -> do
+                         report $ InvalidLang s
+                         return Nothing
+                       Right l -> return (Just l)
+
+-- | Parse a BCP 47 string as a Lang.
+parseBCP47 :: String -> Either String Lang
+parseBCP47 lang =
+  case P.parse bcp47 "lang" lang of
+       Right r -> Right r
+       Left e  -> Left $ show e
+  where bcp47 = do
+          language <- pLanguage
+          script <- P.option "" pScript
+          region <- P.option "" pRegion
+          variants <- P.many pVariant
+          () <$ P.char '-' P.<|> P.eof
+          return $ Lang{ langLanguage = language
+                       , langScript = script
+                       , langRegion = region
+                       , langVariants = variants }
+        asciiLetter = P.satisfy (\c -> isAscii c && isLetter c)
+        pLanguage = do
+          cs <- P.many1 asciiLetter
+          let lcs = length cs
+          guard $ lcs == 2 || lcs == 3
+          return cs
+        pScript = P.try $ do
+          P.char '-'
+          x <- P.satisfy (\c -> isAscii c && isLetter c && isUpper c)
+          xs <- P.count 3
+                 (P.satisfy (\c -> isAscii c && isLetter c && isLower c))
+          return (x:xs)
+        pRegion = P.try $ do
+          P.char '-'
+          cs <- P.many1 asciiLetter
+          let lcs = length cs
+          guard $ lcs == 2 || lcs == 3
+          return cs
+        pVariant = P.try $ do
+          P.char '-'
+          ds <- P.option "" (P.count 1 P.digit)
+          cs <- P.many1 asciiLetter
+          let var = ds ++ cs
+          guard $ if null ds
+                     then length var >= 5 && length var <= 8
+                     else length var == 4
+          return var
diff --git a/src/Text/Pandoc/Writers/Docx.hs b/src/Text/Pandoc/Writers/Docx.hs
index 52ababb14..bc8568cd1 100644
--- a/src/Text/Pandoc/Writers/Docx.hs
+++ b/src/Text/Pandoc/Writers/Docx.hs
@@ -67,7 +67,8 @@ import Text.Pandoc.Shared hiding (Element)
 import qualified Text.Pandoc.UTF8 as UTF8
 import Text.Pandoc.Walk
 import Text.Pandoc.Writers.Math
-import Text.Pandoc.Writers.Shared (fixDisplayMath, getLang, renderLang)
+import Text.Pandoc.Writers.Shared (fixDisplayMath)
+import Text.Pandoc.BCP47 (getLang, renderLang)
 import Text.Printf (printf)
 import Text.TeXMath
 import Text.XML.Light as XML
diff --git a/src/Text/Pandoc/Writers/ODT.hs b/src/Text/Pandoc/Writers/ODT.hs
index 54873efb2..98aa3b30b 100644
--- a/src/Text/Pandoc/Writers/ODT.hs
+++ b/src/Text/Pandoc/Writers/ODT.hs
@@ -50,8 +50,8 @@ import Text.Pandoc.Shared (stringify)
 import Text.Pandoc.UTF8 (fromStringLazy, fromTextLazy, toStringLazy)
 import Text.Pandoc.Walk
 import Text.Pandoc.Writers.OpenDocument (writeOpenDocument)
-import Text.Pandoc.Writers.Shared (fixDisplayMath, getLang, Lang(..),
-           renderLang)
+import Text.Pandoc.Writers.Shared (fixDisplayMath)
+import Text.Pandoc.BCP47 (getLang, Lang(..), renderLang)
 import Text.Pandoc.XML
 import Text.TeXMath
 import Text.XML.Light
diff --git a/src/Text/Pandoc/Writers/OpenDocument.hs b/src/Text/Pandoc/Writers/OpenDocument.hs
index 763cea5ad..6c53ab4ab 100644
--- a/src/Text/Pandoc/Writers/OpenDocument.hs
+++ b/src/Text/Pandoc/Writers/OpenDocument.hs
@@ -50,6 +50,7 @@ import Text.Pandoc.Templates (renderTemplate')
 import Text.Pandoc.Writers.Math
 import Text.Pandoc.Writers.Shared
 import Text.Pandoc.XML
+import Text.Pandoc.BCP47 (parseBCP47, Lang(..))
 import Text.Printf (printf)
 
 -- | Auxiliary function to convert Plain block to Para.
diff --git a/src/Text/Pandoc/Writers/Shared.hs b/src/Text/Pandoc/Writers/Shared.hs
index b56f2d468..2047285eb 100644
--- a/src/Text/Pandoc/Writers/Shared.hs
+++ b/src/Text/Pandoc/Writers/Shared.hs
@@ -29,11 +29,7 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 Shared utility functions for pandoc writers.
 -}
 module Text.Pandoc.Writers.Shared (
-                       getLang
-                     , parseBCP47
-                     , Lang(..)
-                     , renderLang
-                     , metaToJSON
+                       metaToJSON
                      , metaToJSON'
                      , addVariablesToJSON
                      , getField
@@ -46,97 +42,20 @@ module Text.Pandoc.Writers.Shared (
                      , gridTable
                      )
 where
-import Control.Monad (liftM, zipWithM, guard)
+import Control.Monad (liftM, zipWithM)
 import Data.Aeson (FromJSON (..), Result (..), ToJSON (..), Value (Object),
                    encode, fromJSON)
-import Data.Char (isAscii, isLetter, isUpper, isLower)
 import qualified Data.HashMap.Strict as H
-import Data.List (groupBy, intersperse, transpose, intercalate)
+import Data.List (groupBy, intersperse, transpose)
 import qualified Data.Map as M
 import Data.Maybe (isJust)
 import qualified Data.Text as T
 import qualified Data.Traversable as Traversable
 import Text.Pandoc.Definition
-import Text.Pandoc.Class (PandocMonad, report)
-import Text.Pandoc.Logging
 import Text.Pandoc.Options
 import Text.Pandoc.Pretty
 import Text.Pandoc.UTF8 (toStringLazy)
 import Text.Pandoc.XML (escapeStringForXML)
-import qualified Text.Parsec as P
-
--- | Represents BCP 47 language/country code.
-data Lang = Lang{ langLanguage   :: String
-                , langScript     :: String
-                , langRegion     :: String
-                , langVariants   :: [String] }
-                deriving (Eq, Ord, Show)
-
--- | Render a Lang as BCP 47.
-renderLang :: Lang -> String
-renderLang lang = intercalate "-" (langLanguage lang : filter (not . null)
-                    ([langScript lang, langRegion lang] ++ langVariants lang))
-
--- | Get the contents of the `lang` metadata field or variable.
-getLang :: PandocMonad m => WriterOptions -> Meta -> m (Maybe Lang)
-getLang opts meta = case
-  (case lookup "lang" (writerVariables opts) of
-        Just s -> Just s
-        _      ->
-          case lookupMeta "lang" meta of
-               Just (MetaInlines [Str s]) -> Just s
-               Just (MetaString s)        -> Just s
-               _                          -> Nothing) of
-       Nothing -> return Nothing
-       Just s  -> case parseBCP47 s of
-                       Left _ -> do
-                         report $ InvalidLang s
-                         return Nothing
-                       Right l -> return (Just l)
-
--- | Parse a BCP 47 string as a Lang.
-parseBCP47 :: String -> Either String Lang
-parseBCP47 lang =
-  case P.parse bcp47 "lang" lang of
-       Right r -> Right r
-       Left e  -> Left $ show e
-  where bcp47 = do
-          language <- pLanguage
-          script <- P.option "" pScript
-          region <- P.option "" pRegion
-          variants <- P.many pVariant
-          () <$ P.char '-' P.<|> P.eof
-          return $ Lang{ langLanguage = language
-                       , langScript = script
-                       , langRegion = region
-                       , langVariants = variants }
-        asciiLetter = P.satisfy (\c -> isAscii c && isLetter c)
-        pLanguage = do
-          cs <- P.many1 asciiLetter
-          let lcs = length cs
-          guard $ lcs == 2 || lcs == 3
-          return cs
-        pScript = P.try $ do
-          P.char '-'
-          x <- P.satisfy (\c -> isAscii c && isLetter c && isUpper c)
-          xs <- P.count 3
-                 (P.satisfy (\c -> isAscii c && isLetter c && isLower c))
-          return (x:xs)
-        pRegion = P.try $ do
-          P.char '-'
-          cs <- P.many1 asciiLetter
-          let lcs = length cs
-          guard $ lcs == 2 || lcs == 3
-          return cs
-        pVariant = P.try $ do
-          P.char '-'
-          ds <- P.option "" (P.count 1 P.digit)
-          cs <- P.many1 asciiLetter
-          let var = ds ++ cs
-          guard $ if null ds
-                     then length var >= 5 && length var <= 8
-                     else length var == 4
-          return var
 
 -- | Create JSON value for template from a 'Meta' and an association list
 -- of variables, specified at the command line or in the writer.