Created
December 21, 2015 14:57
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Unfold function
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| {-# LANGUAGE ScopedTypeVariables #-} | |
| module UnfoldTree where | |
| data Tree v e = Node v [(e,Tree v e)] | |
| unfold :: forall s v e. (s -> (v, [(e,s)])) -> s -> Tree v e | |
| unfold next seed = uncurry Node $ fmap rec $ next seed where | |
| rec :: [(e,s)] -> [(e, Tree v e)] | |
| rec = fmap $ fmap (unfold next) |
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