[Haskell-cafe] Not in scope

Jochem Berndsen jochem at functor.nl
Sat Apr 25 16:34:07 EDT 2009


siso dagbovie wrote:
> Hi,
> 
> I've defined the datatype:
> 
> data Graph a b = Empty | Context a b :& Graph a b
> 
> and the function
> 
>  isEmpty     :: Graph a b -> Bool
>  isEmpty Empty = True
>  isEmpty _     = False
> 
> and when I do a test run with the graph, 
> ( [ ],2,'c',[("down",3)]) :& Empty
> 
> Haskell is bringing the message "  Not in scope: data constructor `:&' "
> Why is that so?

This works for me. Are the definitions in the same file? Otherwise, you
will need to import your definition.

All the best,
-- 
Jochem Berndsen | jochem at functor.nl
GPG: 0xE6FABFAB


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