The main problem is that you cannot assume Integral for the values 20 and 40. Those have types (Num a=>a). And without the Integral assumption, you cannot define your instance. So what I would do is to create a thin wrapper:
i = id :: Integer -> Integer
and write:
input2 = [ InputDecs [ inp "emaLength" TyNumber ((i 20) + (i 40)) ] ]
Sometimes the simplest solution is the best one Cheers pepe On 07/04/2007, at 14:35, Joel Reymont wrote:
Pepe,
On Apr 7, 2007, at 1:31 PM, Pepe Iborra wrote:
input2 = [ InputDecs [ inp "emaLength" TyNumber ((20::Integer) + (40::Integer)) ] ]
Thank you for your suggestion! I'm trying to make my AST definition as succinct as possible, though, so I would really love to have 20 + 40. The issue is confined to a single module used during testing.
Thanks, Joel