[Haskell-beginners] Application of lookup function

[Alex Belanger]

The (`elem` members) function will tell you if the person is a member of
members. You can then turn that boolean into your custom State type.
On Dec 3, 2015 11:46 PM, "Jeon-Young Kang" <jykang22 at gmail.com> wrote:

> Hi all.
>
> I'd like to apply lookup function (Data.Map) for what I am working on.
>
> Here is my code.
>
> data Person = Person {personId :: Int, name = String}
> data People = [Person]
>
> data State = InMembership | NoMemebership
>
> person1 = Person {1 = personId, "James" = name}
> person2 = Person {2 = personId, "Tom" = name}
>
> members = People [person1, person2]
>
> class Belonging a where
>       belonging :: a -> [a] -> Bool -> State
>
> here is the problem...
> I don't know how to get to know whether a person is belong to members.
> I'd like to find it through a person's name.
>
> Can you suggest any examples??
>
> Sincerely,
> Jeon
>
>
>
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