18 May
2009
18 May
'09
10:26 p.m.
On Mon, May 18, 2009 at 10:02 PM, Ryan Ingram
Unfortunately, you can't derive Show on Chain as defined, because it contains a function:
Sure you can. I just tried the following, and it compiled without complaints.
import Text.Show.Functions
data Chain = Link Int (Int -> Chain) deriving (Show)
The usual warnings about orphan instances apply, but the purpose of
the Text.Show.Functions module is to provide a standard Show instance
for functions so that libraries (e.g., QuickCheck) don't declare
conflicting instances.
--
Dave Menendez