Use safeRead instead of using reads directly (various modules).

4 files changed, 27 insertions, 25 deletions

diff --git a/src/Text/Pandoc.hs b/src/Text/Pandoc.hs
index b65e7130d..6a019bc3f 100644
--- a/src/Text/Pandoc.hs
+++ b/src/Text/Pandoc.hs
@@ -135,6 +135,7 @@ import Text.Pandoc.Writers.Org
 import Text.Pandoc.Writers.AsciiDoc
 import Text.Pandoc.Templates
 import Text.Pandoc.Options
+import Text.Pandoc.Shared (safeRead)
 import Data.ByteString.Lazy (ByteString)
 import Data.Version (showVersion)
 import Text.JSON.Generic
@@ -158,10 +159,9 @@ parseFormatSpec = parse formatSpec ""
         extMod = do
           polarity <- oneOf "-+"
           name <- many1 $ noneOf "-+"
-          ext <- case reads name of
-                       ((n,[]):_) -> return n
-                       _          -> unexpected $ "Unknown extension: " ++
-                                        name
+          ext <- case safeRead name of
+                       Just n  -> return n
+                       Nothing -> unexpected $ "Unknown extension: " ++ name
           return $ case polarity of
                         '-'  -> Set.delete ext
                         _    -> Set.insert ext
diff --git a/src/Text/Pandoc/Highlighting.hs b/src/Text/Pandoc/Highlighting.hs
index 080acebee..95df88099 100644
--- a/src/Text/Pandoc/Highlighting.hs
+++ b/src/Text/Pandoc/Highlighting.hs
@@ -47,6 +47,7 @@ module Text.Pandoc.Highlighting ( languages
                                 , Style
                                 ) where
 import Text.Pandoc.Definition
+import Text.Pandoc.Shared (safeRead)
 import Text.Highlighting.Kate
 import Data.List (find)
 import Data.Maybe (fromMaybe)
@@ -60,9 +61,9 @@ highlight :: (FormatOptions -> [SourceLine] -> a) -- ^ Formatter
           -> String -- ^ Raw contents of the CodeBlock
           -> Maybe a -- ^ Maybe the formatted result
 highlight formatter (_, classes, keyvals) rawCode =
-  let firstNum = case reads (fromMaybe "1" $ lookup "startFrom" keyvals) of
-                      ((n,_):_) -> n
-                      []        -> 1
+  let firstNum = case safeRead (fromMaybe "1" $ lookup "startFrom" keyvals) of
+                      Just n  -> n
+                      Nothing -> 1
       fmtOpts = defaultFormatOpts{
                   startNumber = firstNum,
                   numberLines = any (`elem`
diff --git a/src/Text/Pandoc/Readers/Native.hs b/src/Text/Pandoc/Readers/Native.hs
index 410c44a37..a0e5a0635 100644
--- a/src/Text/Pandoc/Readers/Native.hs
+++ b/src/Text/Pandoc/Readers/Native.hs
@@ -31,6 +31,7 @@ Conversion of a string representation of a pandoc type (@Pandoc@,
 module Text.Pandoc.Readers.Native ( readNative ) where
 
 import Text.Pandoc.Definition
+import Text.Pandoc.Shared (safeRead)
 
 nullMeta :: Meta
 nullMeta = Meta{ docTitle = []
@@ -51,31 +52,31 @@ nullMeta = Meta{ docTitle = []
 readNative :: String      -- ^ String to parse (assuming @'\n'@ line endings)
            -> Pandoc
 readNative s =
-  case reads s of
-       (d,_):_    -> d
-       []         -> Pandoc nullMeta $ readBlocks s
+  case safeRead s of
+       Just d    -> d
+       Nothing   -> Pandoc nullMeta $ readBlocks s
 
 readBlocks :: String -> [Block]
 readBlocks s =
-  case reads s of
-       (d,_):_    -> d
-       []         -> [readBlock s]
+  case safeRead s of
+       Just d    -> d
+       Nothing   -> [readBlock s]
 
 readBlock :: String -> Block
 readBlock s =
-  case reads s of
-       (d,_):_    -> d
-       []         -> Plain $ readInlines s
+  case safeRead s of
+       Just d    -> d
+       Nothing   -> Plain $ readInlines s
 
 readInlines :: String -> [Inline]
 readInlines s =
-  case reads s of
-       (d,_):_    -> d
-       []         -> [readInline s]
+  case safeRead s of
+       Just d     -> d
+       Nothing    -> [readInline s]
 
 readInline :: String -> Inline
 readInline s =
-  case reads s of
-       (d,_):_    -> d
-       []         -> error "Cannot parse document"
+  case safeRead s of
+       Just d     -> d
+       Nothing    -> error "Cannot parse document"
 
diff --git a/src/Text/Pandoc/Writers/EPUB.hs b/src/Text/Pandoc/Writers/EPUB.hs
index 9a6f9670f..1a2764cb6 100644
--- a/src/Text/Pandoc/Writers/EPUB.hs
+++ b/src/Text/Pandoc/Writers/EPUB.hs
@@ -309,9 +309,9 @@ ppTopElement = ("<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n" ++) . unEntity .
         unEntity ('&':'#':xs) =
                    let (ds,ys) = break (==';') xs
                        rest = drop 1 ys
-                   in  case reads ('\'':'\\':ds ++ "'") of
-                          ((x,_):_) -> x : unEntity rest
-                          _         -> '&':'#':unEntity xs
+                   in  case safeRead ('\'':'\\':ds ++ "'") of
+                          Just x   -> x : unEntity rest
+                          Nothing  -> '&':'#':unEntity xs
         unEntity (x:xs) = x : unEntity xs
 
 imageTypeOf :: FilePath -> Maybe String