Hi, I am trying to use Strafunski with GHC 6.5 and was wondering if someone could help me. I have all the instances for Term and Typeable defined for my data types, but when I try to compile with GHC 6.5 I get lots of "overlapping instance" errors. In particular, it seems the instances I am using (generated by DrIFT) are clashing with the ones in Data.Typeable. Is there a way I can fix this? Also I have heard that it is possible to add "deriving Typeable" to each data type and I don't need to use the instances I have created. However, now it complains that it can't find instances for Term - but I can't derive from Term. Does anyone have any ideas how I can get Strafunski working with GHC 6.5? Thanks. Chris. Christopher Brown PhD Student, University of Kent. http://www.cs.kent.ac.uk/people/rpg/cmb21/ cmb21@kent.ac.uk
Christopher Brown wrote:
Hi,
I am trying to use Strafunski with GHC 6.5 and was wondering if someone could help me. I have all the instances for Term and Typeable defined for my data types, but when I try to compile with GHC 6.5 I get lots of "overlapping instance" errors. In particular, it seems the instances I am using (generated by DrIFT) are clashing with the ones in Data.Typeable. Is there a way I can fix this?
Did you try the switch -fallow-overlapping-instances when compiling? Cheers Christian
Christian,
Did you try the switch -fallow-overlapping-instances when compiling?
Yes, but it doesn't seem to make much difference. Cheers, Chris.
Cheers Christian
Christopher Brown PhD Student, University of Kent. http://www.cs.kent.ac.uk/people/rpg/cmb21/ cmb21@kent.ac.uk
Hello Christopher, the trick is that there is another approach to generics, largely based on the Strafunski. it's named "scrap your boilerplate!" (SYB) and it's implementation is included in ghc. you can find 3 SYB papers and it seems better to just learn and use this approach to generic programming instead of Strafunski. in this case you will got automatic Typeable derivation, among other things -- Best regards, Bulat mailto:Bulat.Ziganshin@gmail.com
Christopher Brown wrote:
Christian,
Did you try the switch -fallow-overlapping-instances when compiling?
Yes, but it doesn't seem to make much difference.
Maybe a couple of more library files have not been translated with the above flag. http://article.gmane.org/gmane.comp.lang.haskell.glasgow.bugs/3625 In fact I became a problem with a Show instance and ghc-6.5.20060211 Christian OMDoc/HetsDefs.hs:649:0: Overlapping instances for Show AllMaps arising from use of `GHC.Show.$dmshowList' at OMDoc/HetsDefs.hs:649:0 Matching instances: instance (Show a, Show b, Show c, Show d, Show e, Show f) => Show (a, b, c, d, e, f) -- Imported from GHC.Show instance [overlap ok] Show AllMaps -- Defined at OMDoc/HetsDefs.hs:649:0 In the expression: GHC.Show.$dmshowList In the definition of `showList': showList = GHC.Show.$dmshowList In the definition for method `showList'
Hi Chris, Changes in the libraries of GHC have broken Strafunski compatibility in the past. I have not upgraded to GHC 6.5 myself so I'm not sure if this is the case again. Which versions of DrIFT and Strafunski are you using? Based on what you write, it seems new instances for Typeable have been added to the libs (possibly using deriving), which means some of your own instances are now redundant. You'll have to remove them (which will then break compatibility of your code with 6.4.1, sigh). Alternatively, you may consider to switch from the "drift-default" mode of Strafunski to the "deriving" mode. This means that you will be relying on the Typeable+Data classes rather than on the Typeable +Term classes. You make the switch simply by changing the search path, all your strategic functions should work like before. I guess GHC 6.5 supports deriving both for Typeable and Data (personally, I prefer to use DriFT rather than the deriving clause, because it gives me a bit more control over visibility of instances). For details, see the section "Supported models of functional strategies" in the README file of StrategyLib. Regards, Joost -- Dr. ir. Joost Visser | Departamento de Informática phone +351-253-604461 | Universidade do Minho fax +351-253-604471 | mailto:Joost.Visser@di.uminho.pt mobile +351-91-6253618 | http://www.di.uminho.pt/~joost.visser On Apr 3, 2006, at 3:41 PM, Christopher Brown wrote:
Hi,
I am trying to use Strafunski with GHC 6.5 and was wondering if someone could help me. I have all the instances for Term and Typeable defined for my data types, but when I try to compile with GHC 6.5 I get lots of "overlapping instance" errors. In particular, it seems the instances I am using (generated by DrIFT) are clashing with the ones in Data.Typeable. Is there a way I can fix this?
Also I have heard that it is possible to add "deriving Typeable" to each data type and I don't need to use the instances I have created. However, now it complains that it can't find instances for Term - but I can't derive from Term. Does anyone have any ideas how I can get Strafunski working with GHC 6.5?
Thanks.
Chris.
Christopher Brown PhD Student, University of Kent. http://www.cs.kent.ac.uk/people/rpg/cmb21/ cmb21@kent.ac.uk
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Joost, Thanks very much - this solved my problem! Cheers Chris. On 3 Apr 2006, at 17:03, Joost Visser wrote:
Hi Chris,
Changes in the libraries of GHC have broken Strafunski compatibility in the past. I have not upgraded to GHC 6.5 myself so I'm not sure if this is the case again. Which versions of DrIFT and Strafunski are you using?
Based on what you write, it seems new instances for Typeable have been added to the libs (possibly using deriving), which means some of your own instances are now redundant. You'll have to remove them (which will then break compatibility of your code with 6.4.1, sigh).
Alternatively, you may consider to switch from the "drift-default" mode of Strafunski to the "deriving" mode. This means that you will be relying on the Typeable+Data classes rather than on the Typeable +Term classes. You make the switch simply by changing the search path, all your strategic functions should work like before. I guess GHC 6.5 supports deriving both for Typeable and Data (personally, I prefer to use DriFT rather than the deriving clause, because it gives me a bit more control over visibility of instances). For details, see the section "Supported models of functional strategies" in the README file of StrategyLib.
Regards, Joost
-- Dr. ir. Joost Visser | Departamento de Informática phone +351-253-604461 | Universidade do Minho fax +351-253-604471 | mailto:Joost.Visser@di.uminho.pt mobile +351-91-6253618 | http://www.di.uminho.pt/~joost.visser
On Apr 3, 2006, at 3:41 PM, Christopher Brown wrote:
Hi,
I am trying to use Strafunski with GHC 6.5 and was wondering if someone could help me. I have all the instances for Term and Typeable defined for my data types, but when I try to compile with GHC 6.5 I get lots of "overlapping instance" errors. In particular, it seems the instances I am using (generated by DrIFT) are clashing with the ones in Data.Typeable. Is there a way I can fix this?
Also I have heard that it is possible to add "deriving Typeable" to each data type and I don't need to use the instances I have created. However, now it complains that it can't find instances for Term - but I can't derive from Term. Does anyone have any ideas how I can get Strafunski working with GHC 6.5?
Thanks.
Chris.
Christopher Brown PhD Student, University of Kent. http://www.cs.kent.ac.uk/people/rpg/cmb21/ cmb21@kent.ac.uk
_______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Christopher Brown PhD Student, University of Kent. http://www.cs.kent.ac.uk/people/rpg/cmb21/ cmb21@kent.ac.uk
participants (4)
-
Bulat Ziganshin -
Christian Maeder -
Christopher Brown -
Joost Visser