==================== Derived instances ====================
Derived instances:
instance GHC.Generics.Generic (Temp.X a_adY) where
GHC.Generics.from (Temp.X g1_aeG)
= GHC.Generics.M1
(GHC.Generics.M1 (GHC.Generics.M1 (GHC.Generics.K1 g1_aeG)))
(GHC.Generics.M1 (GHC.Generics.M1 (GHC.Generics.M1 (GHC.Generics.K1 g1_aeH))))
= Temp.X g1_aeH
instance GHC.Generics.Datatype Temp.D1X where
GHC.Generics.datatypeName _ = "X"
GHC.Generics.moduleName _ = "Temp"
instance GHC.Generics.Constructor Temp.C1_0X where
GHC.Generics.conName _ = "X"
GHC.Generics.conIsRecord _ = GHC.Types.True
instance GHC.Generics.Selector Temp.S1_0_0X where
GHC.Generics.selName _ = "myX"
Generic representation:
Generated datatypes for meta-information:
Temp.D1X
Temp.C1_0X
Temp.S1_0_0X
Representation types:
Temp.Rep_X = GHC.Generics.D1
Temp.D1X
(GHC.Generics.C1
Temp.C1_0X
(GHC.Generics.S1 Temp.S1_0_0X (GHC.Generics.Par0 a_adY)))
Still not perfect, in that the representation type should really appear as a type instance inside the Generic instance, but at least all the important information is printed.
Cheers,
Pedro
2011/11/3 Bas van Dijk
<v.dijk.bas@gmail.com>
2011/11/3 José Pedro Magalhães <jpm@cs.uu.nl>:
> "-ddump-deriv" will print (most of) it.
But it doesn't print the most useful piece of information: the
definition of Rep.
It would be great if this could be added.
Currently when I have a type that I want to know the Rep of, say:
data Foo = Bar Int
| Boo {hello :: String}
deriving Generic
I just convert it to a Rep and show it:
err = show $ from $ Boo "World"
However Reps don't have Show instances so GHC complains:
No instance for
(Show (D1 D1Foo ( C1 C1_0Foo (S1 NoSelector (Rec0 Int))
:+: C1 C1_1Foo (S1 S1_1_0Foo (Rec0 String))
)
x0
)
)
arising from a use of `show'
And there you go. This is the only time when I'm happy to see an error
message :-)
Bas