[Haskell-cafe] Reader monad

Albert Y. C. Lai trebla at vex.net
Wed Dec 29 21:27:44 CET 2010

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?


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,

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]

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