[Haskell-cafe] advice on a parsing function
manlio_perillo at libero.it
Wed Mar 11 13:59:25 EDT 2009
minh thu ha scritto:
> The approach I suggested is a bit overkill. You can indeed use L.lines
> to split the input into lines then work on that.
> But still, avoid the pair (Int, Bytestring). Instead, you can basically map
> on each line the unsafeReadInt modified to :
> - return the id
> - return if it is one kind of id or the other kind.
> so :
> type UserId = Int
> type MovieId = Int
> unsafeReadInt :: Line -> Either MovieId UserId
> Now you have a nice list [Either MovieId UserId] that
> you need to transform into (MovieId, [UserId]).
Thanks, this seems a much better solution.
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