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Diffstat (limited to 'progs/lib/hbc/Maybe.hs')
| -rw-r--r-- | progs/lib/hbc/Maybe.hs | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/progs/lib/hbc/Maybe.hs b/progs/lib/hbc/Maybe.hs new file mode 100644 index 0000000..f0ada70 --- /dev/null +++ b/progs/lib/hbc/Maybe.hs @@ -0,0 +1,6 @@ +module Maybe(Maybe(..), thenM) where +-- Maybe together with Just and thenM forms a monad, but is more +-- by accident than by design. +data Maybe a = Nothing | Just a deriving (Eq, Ord, Text, Binary) +Nothing `thenM` _ = Nothing +Just a `thenM` f = f a |