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Diffstat (limited to 'src/GF/Data')
| -rw-r--r-- | src/GF/Data/BacktrackM.hs | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/src/GF/Data/BacktrackM.hs b/src/GF/Data/BacktrackM.hs index 58860d8f6..29bfe0e10 100644 --- a/src/GF/Data/BacktrackM.hs +++ b/src/GF/Data/BacktrackM.hs @@ -94,6 +94,7 @@ instance Monad Backtr where return a = B (\c f -> c a f) B m >>= k = B (\c f -> m (\a -> unBacktr (k a) c) f) where unBacktr (B m) = m + fail _ = failureB failureB = B (\c f -> f) B m |||| B n = B (\c f -> m c (n c f)) @@ -116,3 +117,4 @@ instance Monad (BacktrackM s) where return a = BM (\s -> return (s, a)) BM m >>= k = BM (\s -> do (s', a) <- m s ; unBM (k a) s') where unBM (BM m) = m + fail _ = failure |