From 79ea2dac8f58dace80758c734354258868a1d0a0 Mon Sep 17 00:00:00 2001 From: Bas van Dijk Date: Sun, 16 May 2010 16:06:51 +0000 Subject: [PATCH] Moved MonadPlus instance for STM from Control.Monad.STM to GHC.Conc to avoid an orphaned instance --- GHC/Conc.lhs | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/GHC/Conc.lhs b/GHC/Conc.lhs index 715e569..c1b2107 100644 --- a/GHC/Conc.lhs +++ b/GHC/Conc.lhs @@ -476,6 +476,10 @@ thenSTM (STM m) k = STM ( \s -> returnSTM :: a -> STM a returnSTM x = STM (\s -> (# s, x #)) +instance MonadPlus STM where + mzero = retry + mplus = orElse + -- | Unsafely performs IO in the STM monad. Beware: this is a highly -- dangerous thing to do. -- -- 1.7.10.4