From 10cdd59fa8664caf5ac73dc06ee7076a4bbe69bd Mon Sep 17 00:00:00 2001
From: John MacFarlane <jgm@berkeley.edu>
Date: Thu, 9 Aug 2012 07:52:39 -0700
Subject: Added safeRead to Text.Pandoc.Shared.

---
 src/Text/Pandoc/Shared.hs | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

(limited to 'src/Text')

diff --git a/src/Text/Pandoc/Shared.hs b/src/Text/Pandoc/Shared.hs
index f3ec43a06..9f615867c 100644
--- a/src/Text/Pandoc/Shared.hs
+++ b/src/Text/Pandoc/Shared.hs
@@ -65,7 +65,9 @@ module Text.Pandoc.Shared (
                      readDataFile,
                      -- * Error handling
                      err,
-                     warn
+                     warn,
+                     -- * Safe read
+                     safeRead
                     ) where
 
 import Text.Pandoc.Definition
@@ -489,3 +491,12 @@ warn :: String -> IO ()
 warn msg = do
   name <- getProgName
   UTF8.hPutStrLn stderr $ name ++ ": " ++ msg
+
+--
+-- Safe read
+--
+
+safeRead :: (Monad m, Read a) => String -> m a
+safeRead s = case reads s of
+                  (d,[]):_  -> return d
+                  _         -> fail $ "Could not read `" ++ s ++ "'"
-- 
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