tvl-depot/website/sandbox/chord-drill-sergeant/src/Misc.elm

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Elm
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module Misc exposing (..)
comesAfter : a -> List a -> Maybe a
comesAfter x xs =
case xs of
[] -> Nothing
_::[] -> Nothing
y::z::rest -> if y == x then Just z else comesAfter x (z::rest)
comesBefore : a -> List a -> Maybe a
comesBefore x xs =
case xs of
[] -> Nothing
_::[] -> Nothing
y::z::rest -> if z == x then Just y else comesAfter x (z::rest)