[Haskell-cafe] nice simple problem for someone struggling....

[Nicholls, Mark]

Yes sorry....but this still fails with....

 

"`numberType1' is a rigid type variable bound by"

 

________________________________

From: Brent Yorgey [mailto:byorgey at gmail.com] 
Sent: 21 December 2007 17:29
To: Nicholls, Mark
Cc: Jules Bean; haskell-cafe at haskell.org
Subject: Re: [Haskell-cafe] nice simple problem for someone
struggling....

 

 

	
	"class ShapeInterface shape where
	       area :: shape->Int"

	now looks dubious....I want it to be something like
	
	"class ShapeInterface shape where
	       area :: Num numberType => shape->Int" ?


Rather, I think you probably want

class ShapeInterface shape where
    area :: Num numberType => shape -> numberType

-Brent

 

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