On 27.11.2014 05:08, Karl Voelker wrote:
The error message says that it expected a type. That might be a bit confusing. What it means by "type" is "a thing with kind *". That is the kind of types, and those types are the only things which have values. The argument to a function must be a value, so the argument to the "->" operator must be a type. But why is it expecting type of kind '*' and rejecting type of kind 'CmdKind'? Functions are limited to work on types of kind '*'?
I don't think it's clear what you are trying to do, so it is hard to say what you should write. I wanted to declare a class for that can only be instantiated for types of certain kind, and then create instances for all that types in a single statement. Basically, I was just trying to understand how kinds and type classes are related. Also, trying to save some typing.
-- Thank you, Wojtek Narczynski