Docx reader: Parse instrText info in fldChar tags.

We introduce a new module, Text.Pandoc.Readers.Docx.Fields which
contains a simple parsec parser. At the moment, only simple hyperlink
fields are accepted, but that can be extended in the future.

2 files changed, 102 insertions, 5 deletions

diff --git a/src/Text/Pandoc/Readers/Docx/Fields.hs b/src/Text/Pandoc/Readers/Docx/Fields.hs
new file mode 100644
index 000000000..69758b431
--- /dev/null
+++ b/src/Text/Pandoc/Readers/Docx/Fields.hs
@@ -0,0 +1,89 @@
+{-
+Copyright (C) 2014-2018 Jesse Rosenthal <jrosenthal@jhu.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.Readers.Docx.Fields
+   Copyright   : Copyright (C) 2014-2018 Jesse Rosenthal
+   License     : GNU GPL, version 2 or above
+
+   Maintainer  : Jesse Rosenthal <jrosenthal@jhu.edu>
+   Stability   : alpha
+   Portability : portable
+
+For parsing Field definitions in instText tags, as described in
+ECMA-376-1:2016, §17.16.5 -}
+
+module Text.Pandoc.Readers.Docx.Fields ( FieldInfo(..)
+                                       , parseFieldInfo
+                                       ) where
+
+import Text.Parsec
+import Text.Parsec.String (Parser)
+
+type URL = String
+
+data FieldInfo = HyperlinkField URL
+               | UnknownField
+               deriving (Show)
+
+parseFieldInfo :: String -> Either ParseError FieldInfo
+parseFieldInfo = parse fieldInfo ""
+
+fieldInfo :: Parser FieldInfo
+fieldInfo =
+  (try $ HyperlinkField <$> hyperlink)
+  <|>
+  return UnknownField
+
+escapedQuote :: Parser String
+escapedQuote = string "\\\""
+
+inQuotes :: Parser String
+inQuotes = do
+  (try escapedQuote) <|> (anyChar >>= (\c -> return [c]))
+
+quotedString :: Parser String
+quotedString = do
+  char '"'
+  concat <$> manyTill inQuotes (try (char '"'))
+
+unquotedString :: Parser String
+unquotedString = manyTill anyChar (try (space))
+
+fieldArgument :: Parser String
+fieldArgument = quotedString <|> unquotedString
+
+-- there are other switches, but this is the only one I've seen in the wild so far, so it's the first one I'll implement. See §17.16.5.25
+hyperlinkSwitch :: Parser (String, String)
+hyperlinkSwitch = do
+  sw <- string "\\l"
+  spaces
+  farg <- fieldArgument
+  return (sw, farg)
+
+hyperlink :: Parser URL
+hyperlink = do
+  many space
+  string "HYPERLINK"
+  spaces
+  farg <- fieldArgument
+  switches <- (spaces *> many hyperlinkSwitch)
+  let url = case switches of
+              ("\\l", s) : _ -> farg ++ ('#': s)
+              _              -> farg
+  return url
diff --git a/src/Text/Pandoc/Readers/Docx/Parse.hs b/src/Text/Pandoc/Readers/Docx/Parse.hs
index b3a0fee8e..5f648666f 100644
--- a/src/Text/Pandoc/Readers/Docx/Parse.hs
+++ b/src/Text/Pandoc/Readers/Docx/Parse.hs
@@ -54,6 +54,7 @@ module Text.Pandoc.Readers.Docx.Parse ( Docx(..)
                                       , TrackedChange(..)
                                       , ChangeType(..)
                                       , ChangeInfo(..)
+                                      , FieldInfo(..)
                                       , archiveToDocx
                                       , archiveToDocxWithWarnings
                                       ) where
@@ -70,6 +71,7 @@ import qualified Data.Map as M
 import Data.Maybe
 import System.FilePath
 import Text.Pandoc.Readers.Docx.Util
+import Text.Pandoc.Readers.Docx.Fields
 import Text.Pandoc.Shared (filteredFilesFromArchive, safeRead)
 import qualified Text.Pandoc.UTF8 as UTF8
 import Text.TeXMath (Exp)
@@ -286,10 +288,6 @@ data Run = Run RunStyle [RunElem]
          | InlineChart          -- placeholder
            deriving Show
 
-data FieldInfo = HyperlinkField URL
-               | UnknownField
-               deriving (Show)
-
 data RunElem = TextRun String | LnBrk | Tab | SoftHyphen | NoBreakHyphen
              deriving Show
 
@@ -802,9 +800,19 @@ elemToParPart ns element
           return NullParPart
         FldCharContent info runs | fldCharType == "end" -> do
           modify $ \st -> st {stateFldCharState = FldCharClosed}
-          return $ Field info runs
+          return $ Field info $ reverse runs
         _ -> throwError WrongElem
 elemToParPart ns element
+  | isElem ns "w" "r" element
+  , Just instrText <- findChildByName ns "w" "instrText" element = do
+      fldCharState <- gets stateFldCharState
+      case fldCharState of
+        FldCharOpen -> do
+          info <- eitherToD $ parseFieldInfo $ strContent instrText
+          modify $ \st -> st{stateFldCharState = FldCharFieldInfo info}
+          return NullParPart
+        _ -> return NullParPart
+elemToParPart ns element
   | isElem ns "w" "r" element = do
     run <- elemToRun ns element
     -- we check to see if we have an open FldChar in state that we're