[Haskell-cafe] monads with take-out options

[Jason Dagit]

2008/11/24 Greg Meredith <lgreg.meredith at biosimilarity.com>

> Haskellians,
> Some monads come with take-out options, e.g.
>
>    - List
>    - Set
>
> In the sense that if unit : A -> List A is given by unit a = [a], then
> taking the head of a list can be used to retrieve values from inside the
> monad.
>
> Some monads do not come with take-out options, IO being a notorious
> example.
>

I think the take-out option for IO is usually called 'main'. :)

Jason
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