This doesn't work:
-- packages: template-haskell
{-# OPTIONS_GHC -XTemplateHaskell #-}
module Main where
import Language.Haskell.TH
data A a = A a
type C = A Int
data ABC = ABC Int
$(do
a <- reify $ mkName "C"
report False $ show a
return []
)
main = print ""
|| [1 of 1] Compiling Main ( test.hs, test.o )
||
test.hs|1| `C' is not in scope at a reify
Using mkName "A" results in
test.hs|1 error|
|| DataConI Main.A (ForallT [a_1627391370] [] (AppT (AppT ArrowT (VarT a_1627391370)) (AppT (ConT Main.A) (VarT a_1627391370)))) Main.A (Fixity 9 InfixL)
as expected
Why do I need it?
I'd like to implement kind of very basic relational data representation
the way IxSet is doing it but without dynamics..
It will look like this:
type CDs = Table (Autoinc, Artist, Title, Year) -- col types
(Artist, Title, Year) -- keys
() -- is detail of
type Tracks = Table (Autoinc, Title, RecordingDate)
(Title, RecordingDate)
(CDs)
$(mkDB ["CDs","Tracks"])
To be able to automatically derive
insert{CDs,Tracks}
delete{CDs,Tracks}
update{CDs,Tracks}
functions I need to get information about those types.. Is this
possible?
Thanks
Marc Weber
