moved all old source code to src-2.9 ; src will be for GF 3 development

1 files changed, 38 insertions, 0 deletions

diff --git a/src-2.9/GF/Data/ErrM.hs b/src-2.9/GF/Data/ErrM.hs
new file mode 100644
index 000000000..e8cea12d4
--- /dev/null
+++ b/src-2.9/GF/Data/ErrM.hs
@@ -0,0 +1,38 @@
+----------------------------------------------------------------------
+-- |
+-- Module      : ErrM
+-- Maintainer  : AR
+-- Stability   : (stable)
+-- Portability : (portable)
+--
+-- > CVS $Date: 2005/04/21 16:22:00 $ 
+-- > CVS $Author: bringert $
+-- > CVS $Revision: 1.5 $
+--
+-- hack for BNFC generated files. AR 21/9/2003
+-----------------------------------------------------------------------------
+
+module GF.Data.ErrM (Err(..)) where
+
+import Control.Monad (MonadPlus(..))
+
+-- | like @Maybe@ type with error msgs
+data Err a = Ok a | Bad String
+  deriving (Read, Show, Eq)
+
+instance Monad Err where
+  return      = Ok
+  fail        = Bad
+  Ok a  >>= f = f a
+  Bad s >>= f = Bad s
+
+-- | added 2\/10\/2003 by PEB
+instance Functor Err where
+  fmap f (Ok a) = Ok (f a)
+  fmap f (Bad s) = Bad s
+
+-- | added by KJ
+instance MonadPlus Err where
+    mzero = Bad "error (no reason given)"
+    mplus (Ok a)  _ = Ok a
+    mplus (Bad s) b = b