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| author | krasimir <krasimir@chalmers.se> | 2009-12-13 18:50:29 +0000 |
|---|---|---|
| committer | krasimir <krasimir@chalmers.se> | 2009-12-13 18:50:29 +0000 |
| commit | f85232947e74ee7ef8c7b0ad2338212e7e68f1be (patch) | |
| tree | 667b886a5e3a4b026a63d4e3597f32497d824761 /src/compiler/GF/Data/ErrM.hs | |
| parent | d88a865faff59c98fc91556ff8700b10ee5f2df8 (diff) | |
reorganize the directories under src, and rescue the JavaScript interpreter from deprecated
Diffstat (limited to 'src/compiler/GF/Data/ErrM.hs')
| -rw-r--r-- | src/compiler/GF/Data/ErrM.hs | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/src/compiler/GF/Data/ErrM.hs b/src/compiler/GF/Data/ErrM.hs new file mode 100644 index 000000000..e8cea12d4 --- /dev/null +++ b/src/compiler/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 |
