On 12 March 2011 21:53, Adam Megacz <[email protected]> wrote:
> Did HelloWorld work? See the commands here
I'm not sure what you mean by HelloWorld - it doesn't seem to be
mentioned on that page. However, I have just tried out "pow" and had
exactly the same problem.
The pow example on your page doesn't work as stated. I think that you instead of
(*) :: forall a. <[ Int -> Int -> Int ]>@a
You need
<[ (*) ]> :: forall a. <[ Int -> Int -> Int ]>@a
And you also need something like this declaration:
<[ fromInteger ]> :: forall a. <[ Integer -> Int ]>@a
However, it's easier just to use GHC.HetMet.CodeTypes for these
definitions. Here is the complete example:
{{{
{-# LANGUAGE ModalTypes, FlexibleContexts #-}
{-# LANGUAGE MultiParamTypeClasses #-}
module Foo where
import Control.Arrow
import Prelude
import GHC.HetMet.CodeTypes hiding ((-)) -- For code-typed fromInteger
and friends
import GHC.HetMet.GArrow
-- Included so I can actually run some code (in theory), and my build
doesn't have your newly-added instances
instance GArrow (->) (,) where
ga_id = arr Prelude.id
ga_comp = (>>>)
ga_first = first
ga_second = second
ga_cancell = arr (\((),x) -> x)
ga_cancelr = arr (\(x,()) -> x)
ga_uncancell = arr (\x -> ((),x))
ga_uncancelr = arr (\x -> (x,()))
ga_assoc = arr (\((x,y),z) -> (x,(y,z)))
ga_unassoc = arr (\(x,(y,z)) -> ((x,y),z))
instance GArrowDrop (->) (,) where
ga_drop = arr (\x -> ())
instance GArrowCopy (->) (,) where
ga_copy = arr (\x -> (x,x))
instance GArrowSwap (->) (,) where
ga_swap = arr (\(x,y) -> (y,x))
instance GArrowLoop (->) (,) where
ga_loop = loop
pow :: forall a. (GuestLanguageFromInteger a Int, GuestLanguageMult a
Int) => Int -> <[ Int -> Int ]>@a
pow n =
if n==0
then <[ \x -> 1 ]>
else <[ \x -> x * ~~(pow $ n-1) x ]>
ifThenElse :: Bool -> a -> a -> a
ifThenElse True x y = x
ifThenElse False x y = y
-- Should print 4^3 == 64
main = print i
where
i :: Int
i = flatten (pow 3) 4
}}}
This doesn't compile because the "flatten" function you claim is
exported from GHC.HetMet.CodeTypes doesn't exist. There is a
hetmet_flatten but it is commented out for some reason.
Even if you remove the "main" definition, I get exactly the same error
as before:
{{{
$ ~/Programming/Checkouts/ghc-garrows/inplace/bin/ghc-stage2
-ddump-types GArrows-Pow.hs -dcoqpass -fforce-recomp
[1 of 1] Compiling Foo ( GArrows-Pow.hs, GArrows-Pow.o )
TYPE SIGNATURES
ifThenElse :: forall a. Bool -> a -> a -> a
pow :: forall a.
(GuestLanguageFromInteger a Int, GuestLanguageMult a Int) =>
Int -> <[Int -> Int]>@a
TYPE CONSTRUCTORS
INSTANCES
instance GArrowLoop (->) (,) -- Defined at GArrows-Pow.hs:34:10-28
instance GArrowSwap (->) (,) -- Defined at GArrows-Pow.hs:31:10-28
instance GArrowCopy (->) (,) -- Defined at GArrows-Pow.hs:28:10-28
instance GArrowDrop (->) (,) -- Defined at GArrows-Pow.hs:25:10-28
instance GArrow (->) (,) -- Defined at GArrows-Pow.hs:13:10-24
Dependent modules: []
Dependent packages: [base, ghc-prim, integer-gmp]
==================== Coq Pass Output ====================ghc-stage2:
panic! (the 'impossible' happened)
(GHC version 7.1.20110308 for i386-apple-darwin):
unable to convert HaskWeak to HaskStrong due to:\n type mismatch in
HaskWeak ELet: a and GHC.Types.Bool
Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug
}}}
What am I doing wrong?
Cheers,
Max
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