optional arguments in haskell

Posted by snorlaks on Stack Overflow See other posts from Stack Overflow or by snorlaks
Published on 2010-05-07T18:39:13Z Indexed on 2010/05/07 18:48 UTC
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haskell

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constructor

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parameters

Hello,

I have declared my own type:

data Book = Bookinfo { bookId :: Int, title :: String } deriving(Show)

and now:

x = Bookinfo

it is all ok, valid statement

but making bookId x throws an error.

If I would be able to handle errors in Haskell that would be ok but right now I cant do this So Im curious how to make not specified values of fields take default value, and what exactly value is there when I'm not giving vcalues of fields in construcotr ?

thanks for help

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