[Haskell-cafe] Reader monad

[Albert Y. C. Lai]

On 10-12-29 12:50 PM, michael rice wrote:
> I think of (r -> m a) as a type signature and Int or Bool by themselves
> as types. So, all type signatures are themselves types?

http://www.haskell.org/onlinereport/haskell2010/haskellch4.html#x10-620004

In particular

gendecl → vars :: [context =>] type    (type signature)

Therefore I think of

n :: Int
f :: r -> m a

as type signatures, and their right-hand sides alone,

Int
r -> m a

as types.

I also include the "context =>" part in my types, for example

m :: Num a => a

I take the type to be

Num a => a

The grammar splits out the "context =>" part just for the sake of reuse 
in other places such as

topdecl → ...
	| data [context =>] simpletype [= constrs] [deriving]