Difference between revisions of "Solution2.html"
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− | Alternative grandparent: |
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+ | This next solution will not work. If the sheep has a father and only a maternal grandparent, this function will return Nothing: |
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<haskell> |
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grandparent :: Sheep -> Maybe Sheep |
grandparent :: Sheep -> Maybe Sheep |
Revision as of 17:49, 10 June 2013
parent :: Sheep -> Maybe Sheep
parent s = father s `mplus` mother s
grandparent :: Sheep -> Maybe Sheep
grandparent s = paternalGrandfather s `mplus`
paternalGrandmother s `mplus`
maternalGrandfather s `mplus`
maternalGrandmother s
This next solution will not work. If the sheep has a father and only a maternal grandparent, this function will return Nothing:
grandparent :: Sheep -> Maybe Sheep
grandparent s = parent s >>= parent