17 Aug
2007
17 Aug
'07
9:11 a.m.
Hi all. I want to create the following polymorphic type (EnvItem) that we can apply two functions (envKey and envValue). I tried the following:
type Key = String
data EnvItem a = EnvItem (Key, a)
envKey :: EnvItem (Key, a) -> String envKey EnvItem (key, value) = key
envValue :: EnvValue(Key, a) -> a envValue EnvItem (key, value) = value
But this is resulting in the error: [Constructor "EnvItem" must have exactly 1 argument in pattern] I think this is a very basic problem, but I don't know what is wrong. Regards, Rodrigo.