2016-03-17 01:38:35 +00:00
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module Sublist (..) where
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2016-03-17 01:38:51 +00:00
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2015-10-12 16:46:15 +00:00
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2016-04-10 03:15:51 +00:00
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type ListComparison
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= Equal
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| Superlist
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| Sublist
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| Unequal
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2016-03-17 01:38:51 +00:00
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2016-04-10 03:15:51 +00:00
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sublist : List a -> List a -> ListComparison
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2015-10-12 16:46:15 +00:00
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sublist alist blist =
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2016-03-17 01:38:51 +00:00
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if alist == blist then
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2016-04-10 03:15:51 +00:00
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Equal
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2016-03-17 01:38:51 +00:00
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else if inList alist blist then
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2016-04-10 03:15:51 +00:00
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Superlist
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2016-03-17 01:38:51 +00:00
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else if inList blist alist then
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2016-04-10 03:15:51 +00:00
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Sublist
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2016-03-17 01:38:51 +00:00
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else
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2016-04-10 03:15:51 +00:00
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Unequal
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2016-03-17 01:38:51 +00:00
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2015-10-12 16:46:15 +00:00
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inList : List a -> List a -> Bool
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inList alist blist =
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2016-03-17 01:38:51 +00:00
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let
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getLastInList sublist =
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Maybe.withDefault [] (List.tail sublist)
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2015-10-12 16:46:15 +00:00
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in
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2016-03-17 01:38:51 +00:00
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if (List.length alist) < (List.length blist) then
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False
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else if (List.take (List.length blist) alist) == blist then
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True
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else
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inList (getLastInList alist) blist
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