Re: [Haskell] problem building syb-generics
On Tuesday 04 July 2006 13:20, Simon Peyton-Jones wrote: Lexically-scoped type variables are undergoing a slight upheaval in GHC 6.6 that has not quite settled, and that is what you are running into. Thanks for the help. After a lot of trial error, and reading and stuff I've got past the problems introduced by lexicals. Now I'm hitting another problem. I think there's a missmatch between Maybe (c a) returned by dataCast1 and Maybe (c (t' a)) returned by gcast1. Is this dues to something stupid I have done, or bit-rot between the two libraries? Thanks Matthew Data/Generics2/Instances.hs:290:17: Couldn't match expected type `forall a1. (Data ctx a1) = c (t a1)' against inferred type `c1 (t1 a1)' Expected type: (forall a2. (Data ctx a2) = c (t a2)) - Maybe (c [a]) Inferred type: c1 (t1 a1) - Maybe (c1 (t' a1)) In the expression: gcast1 In the definition of `dataCast1': dataCast1 _ = gcast1 The type of gcast is: Data.Typeable. gcast1 :: (Typeable1 t, Typeable1 t') = c (t a) - Maybe (c (t' a)) And the dataCast1 signature (in Data.Generics2.Basics) is: class (Typeable a, Sat (ctx a)) = Data ctx a where -- | Mediate types and unary type constructors dataCast1 :: Typeable1 t = ctx () - (forall a. Data ctx a = c (t a)) - Maybe (c a) ... The implementation (in Data.Generics2.Instances) is: instance (Sat (ctx [a]), Data ctx a) = Data ctx [a] where dataCast1 _ = gcast1 ... ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re: Is this test summary good or bad?
On Jul 11, 2006, at 11:00 AM, Simon Marlow wrote: Which ones hang? Could you take one of the hanging tests, compile it with -debug, run with +RTS -Ds, and send us the output? What ends up happening is this: 28683 p2 S 0:00.11 ../../timeout/timeout 300 cd ./typecheck/ should_compile '/Users/joelr/work/Haskell/ghc/compiler/stage2/ghc- inplace' -no-recomp -dcore-lint -dcmm-lint -Di386_apple_darwin -c tc033.hs -fno-warn-incomplete-patterns tc033.comp.stderr 21 29125 p2 R 1:53.48 ../../timeout/timeout 300 cd ./typecheck/ should_fail '/Users/joelr/work/Haskell/ghc/compiler/stage2/ghc- inplace' -no-recomp -dcore-lint -dcmm-lint -Di386_apple_darwin -c tcfail011.hstcfail011.comp.stderr 21 Now, these things have been running there forever and I'm not even sure it's a Haskell problem. I suppose the test harness should have terminated the test after 300 seconds but didn't. If I try to re-run the first process by hand it finishes instantly. If I try to re-run the whole thing as above, putting everything after 300 in double quotes it also finishes instantly. -- http://wagerlabs.com/ ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re: RULES pragmas
Malcolm.Wallace:
I have a question about {-# RULES #-} pragmas. Here is a very simple
attempt to use them:
module Simplest where
{-# RULES
simplestRule forall x. id (id x) = x
#-}
myDefn = id (id 42)
I want to verify whether ghc-6.4.1 does actually fire this rule, but
have so far been unable to do so. According to the manual (section
7.10.5), the flag -ddump-rules should list simplestRule if it has been
parsed correctly, and -ddump-simpl-stats should list the number of times
it has fired. But it does not appear in either listing.
Reasoning that I have the syntax wrong, I have tried numerous variations
on the indentation, added type signatures, etc., all to no avail.
So what am I doing wrong? And is there any way to ask the compiler to
give a warning if the RULES pragma contains errors?
In this case, it's because it's missing -fglasgow-exts, I think.
The following works for me with both 6.4 and 6.5 compilers:
module Simplest where
{-# RULES
simplestRule forall x. id (id x) = x
#-}
myDefn = id (id 42)
when compiled with:
$ ghc-6.4.2 -fglasgow-exts -c -ddump-simpl-stats A.hs
Grand total simplifier statistics
Total ticks: 11
2 PreInlineUnconditionally
3 PostInlineUnconditionally
1 UnfoldingDone
1 RuleFired
1 simplestRule
4 BetaReduction
2 SimplifierDone
However, in general, you need to be careful that your identifiers
weren't inlined in the first phase. To control this we add an INLINE [1]
pragma to identifiers we want to match in rules, to ensure they haven't
disappeared by the time the rule matching comes around.
Also, you need -O to have rules kick in locally.
So,
module Simplest where
{-# RULES
simplestRule forall x. myid (myid x) = x
#-}
myDefn = myid (myid 42)
myid x = x
{-# INLINE [1] myid #-}
And:
$ ghc-6.4.2 -fglasgow-exts -O -c -ddump-simpl-stats A.hs
Grand total simplifier statistics
Total ticks: 15
6 PreInlineUnconditionally
2 UnfoldingDone
1 RuleFired
1 simplestRule
5 BetaReduction
1 KnownBranch
8 SimplifierDone
Cheers,
Don
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