1 files changed, 39 insertions, 0 deletions
diff --git a/src/Text/Pandoc/Error.hs b/src/Text/Pandoc/Error.hs
new file mode 100644
index 000000000..d4172f7ca
--- /dev/null
+++ b/src/Text/Pandoc/Error.hs
@@ -0,0 +1,39 @@
+module Text.Pandoc.Error (PandocError(..), handleError,hush, mapLeft) where
+
+import Text.Parsec.Error
+import Text.Parsec.Pos hiding (Line)
+import Text.Pandoc.Compat.Except
+
+type Input = String
+
+data PandocError = ParseFailure String
+                 | ParsecError Input ParseError
+                 deriving (Show)
+
+
+instance Error PandocError where
+  strMsg = ParseFailure
+
+
+mapLeft :: (a -> b) -> Either a c -> Either b c
+mapLeft f (Left x) = Left (f x)
+mapLeft _ (Right x) = Right x
+
+hush :: Either a b -> Maybe b
+hush (Left _) = Nothing
+hush (Right x) = Just x
+
+handleError :: Either PandocError a -> a
+handleError (Right r) = r
+handleError (Left err) =
+  case err of
+    ParseFailure string -> error string
+    ParsecError input err' ->
+        let errPos = errorPos err'
+            errLine = sourceLine errPos
+            errColumn = sourceColumn errPos
+            theline = (lines input ++ [""]) !! (errLine - 1)
+        in  error $ "\nError at " ++ show  err' ++ "\n" ++
+                theline ++ "\n" ++ replicate (errColumn - 1) ' ' ++
+                "^"
+