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Diffstat (limited to 'src/client/Utils/Maybe.elm')
-rw-r--r-- | src/client/Utils/Maybe.elm | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/src/client/Utils/Maybe.elm b/src/client/Utils/Maybe.elm new file mode 100644 index 0000000..46456e1 --- /dev/null +++ b/src/client/Utils/Maybe.elm @@ -0,0 +1,34 @@ +module Utils.Maybe exposing + ( isJust + , cat + , toList + , orElse + ) + +isJust : Maybe a -> Bool +isJust maybe = + case maybe of + Just _ -> True + Nothing -> False + +cat : List (Maybe a) -> List a +cat = + List.foldr + (\mb xs -> + case mb of + Just x -> x :: xs + Nothing -> xs + ) + [] + +toList : Maybe a -> List a +toList mb = + case mb of + Just a -> [a] + Nothing -> [] + +orElse : Maybe a -> Maybe a -> Maybe a +orElse mb1 mb2 = + case mb1 of + Just x -> Just x + Nothing -> mb2 |