It is a bug... we weren't printing enough in -fext-core. I think it's fixed now. (I'm away till Monday.) Simon | -----Original Message----- | From: Hal Daume III [mailto:hdaume@ISI.EDU] | Sent: 29 October 2002 17:57 | To: GHC Users Mailing List | Subject: problem generating Core with no-implicit-prelude | | Hi all, | | I think there's a problem with the external core generation. Suppose we | have the following module: | | ----- | module Test where | | data Bool = True | False | data Maybe a = Just a | Nothing | | class Eq a where | (==) :: a -> a -> Bool | | instance Eq Bool where | (==) True True = True | (==) False False = True | (==) _ _ = False | | instance Eq a => Eq (Maybe a) where | (==) Nothing Nothing = True | (==) (Just a) (Just b) = (==) a b | (==) _ _ = False | ----- | | We compile this using: | ghc -fext-core -fno-code test.hs -fno-implicit-prelude | | Now, if we look at the core, inside the definition of Test.zdfEqMaybe (the | eq function for Maybe a), it essentially looks like (glossing over some of | the extraneous stuff): | | Test.zdfEqMaybe = \ zddEq -> Test.ZCDEq | \ ds ds1 -> | case ds of | Nothing -> case ds1 of | Test.Just a1 -> Test.zdwFalse | Test.Nothing -> Test.zdwTrue | Just a1 -> case ds1 of | Test.Nothing -> Test.zdwFalse | Test.Just b -> Test.zeze zddEq a1 b | | Now, the problem is that "Test.ZCDEq" isn't defined anywhere in the core | file produced and neither is Test.zeze. | | If this is indeed a bug, could someone fix it? If not, could someone tell | me what I'm doing wrong (I could be misreading the Core, but I don't think | so). | | - Hal | | p.s., the full core output reads: | | %module Test | %data Test.Bool = | {Test.True; | Test.False}; | %data Test.Maybe a = | {Test.Just a; | Test.Nothing}; | %newtype Test.ZCTEq a = GHCziPrim.ZLzmzgZR | a | (GHCziPrim.ZLzmzgZR a Test.Bool); | Test.zdfEqBool :: GHCziPrim.ZLzmzgZR | Test.Bool | (GHCziPrim.ZLzmzgZR Test.Bool Test.Bool) = | \ (ds::Test.Bool) (ds1::Test.Bool) -> | %case ds %of (wild::Test.Bool) | {Test.False -> | %case ds1 %of (wild1::Test.Bool) | {Test.True -> | Test.zdwFalse; | Test.False -> | Test.zdwTrue}; | Test.True -> | ds1}; | Test.zdfEqMaybe :: %forall a . GHCziPrim.ZLzmzgZR | (GHCziPrim.ZLzmzgZR a (GHCziPrim.ZLzmzgZR | a Test.Bool)) | (GHCziPrim.ZLzmzgZR | (Test.Maybe a) | (GHCziPrim.ZLzmzgZR (Test.Maybe | a) Test.Bool)) = | %note "InlineMe" | \ @ a | (zddEq::GHCziPrim.ZLzmzgZR a (GHCziPrim.ZLzmzgZR a Test.Bool)) -> | Test.ZCDEq @ (Test.Maybe a) | (\ (ds::Test.Maybe a) (ds1::Test.Maybe a) -> | %case ds %of (wild::Test.Maybe a) | {Test.Nothing -> | %case ds1 %of (wild1::Test.Maybe a) | {Test.Just (a1::a) -> | Test.zdwFalse; | Test.Nothing -> | Test.zdwTrue}; | Test.Just (a1::a) -> | %case ds1 %of (wild1::Test.Maybe a) | {Test.Nothing -> | Test.zdwFalse; | Test.Just (b::a) -> | Test.zeze @ a zddEq a1 b}}); | | -- | Hal Daume III | | "Computer science is no more about computers | hdaume@isi.edu | than astronomy is about telescopes." -Dijkstra | www.isi.edu/~hdaume | | _______________________________________________ | Glasgow-haskell-users mailing list | Glasgow-haskell-users@haskell.org | http://www.haskell.org/mailman/listinfo/glasgow-haskell-users