Move CR filtering from tabFilter to the readers.

The readers previously assumed that CRs had been filtered
from the input.  Now we strip the CRs in the readers themselves,
before parsing.  (The point of this is just to simplify the
parsers.)

Shared now exports a new function `crFilter`. [API change]
And `tabFilter` no longer filters CRs.

1 files changed, 8 insertions, 4 deletions

diff --git a/src/Text/Pandoc/Shared.hs b/src/Text/Pandoc/Shared.hs
index 7b299c56b..53fd38ffd 100644
--- a/src/Text/Pandoc/Shared.hs
+++ b/src/Text/Pandoc/Shared.hs
@@ -49,6 +49,7 @@ module Text.Pandoc.Shared (
                      toRomanNumeral,
                      escapeURI,
                      tabFilter,
+                     crFilter,
                      -- * Date/time
                      normalizeDate,
                      -- * Pandoc block and inline list processing
@@ -279,13 +280,12 @@ escapeURI = escapeURIString (not . needsEscaping)
   where needsEscaping c = isSpace c || c `elem`
                            ['<','>','|','"','{','}','[',']','^', '`']
 
--- | Convert tabs to spaces and filter out DOS line endings.
--- Tabs will be preserved if tab stop is set to 0.
+-- | Convert tabs to spaces. Tabs will be preserved if tab stop is set to 0.
 tabFilter :: Int       -- ^ Tab stop
           -> T.Text    -- ^ Input
           -> T.Text
-tabFilter tabStop = T.filter (/= '\r') . T.unlines .
-    (if tabStop == 0 then id else map go) . T.lines
+tabFilter 0 = id
+tabFilter tabStop = T.unlines . map go . T.lines
   where go s =
          let (s1, s2) = T.break (== '\t') s
          in  if T.null s2
@@ -294,6 +294,10 @@ tabFilter tabStop = T.filter (/= '\r') . T.unlines .
                        (tabStop - (T.length s1 `mod` tabStop)) (T.pack " ")
                        <> go (T.drop 1 s2)
 
+-- | Strip out DOS line endings.
+crFilter :: T.Text -> T.Text
+crFilter = T.filter (/= '\r')
+
 --
 -- Date/time
 --