From dbe8e61acc616b8f5ac07e8df89eb98a7997c29d Mon Sep 17 00:00:00 2001 From: bringert Date: Fri, 25 Nov 2005 16:36:19 +0000 Subject: Move transfer into the GF repo. --- src/Transfer/ErrM.hs | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) create mode 100644 src/Transfer/ErrM.hs (limited to 'src/Transfer/ErrM.hs') diff --git a/src/Transfer/ErrM.hs b/src/Transfer/ErrM.hs new file mode 100644 index 000000000..1f3c566fd --- /dev/null +++ b/src/Transfer/ErrM.hs @@ -0,0 +1,16 @@ +-- BNF Converter: Error Monad +-- Copyright (C) 2004 Author: Aarne Ranta + +-- This file comes with NO WARRANTY and may be used FOR ANY PURPOSE. +module Transfer.ErrM where + +-- the Error monad: 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 -- cgit v1.2.3