[Haskell-cafe] Not in scope

siso dagbovie kisiso10 at yahoo.fr
Sat Apr 25 16:24:22 EDT 2009


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?


 Kind regards

-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://www.haskell.org/pipermail/haskell-cafe/attachments/20090425/19cc5499/attachment.htm

More information about the Haskell-Cafe mailing list