Hello, I am new to Haskell and eager to learn what I believe is an exciting language. I have recently attempted to load the ProviderLookupApp module attached and received the following error message: ProviderLookupApp.hs:14:8: Could not find module `Data.List.Utils': Use -v to see a list of the files searched for. I then located the Data.List.Utils module and attempted to load that but received the error message: Data.List.Utils.hs:63:8: Ambiguous module name `Control.Monad.State': it was found in multiple packages: monads-fd-0.2.0.0 mtl-2.0.1.0 Failed, modules loaded: none. I am running in the Windows environment. Any assistance in this matter would be greatly appreciated. Additionally, exactly how is the -v argument used? Thanks. Regards, CEO'Riley Charles E. O'Riley Jr.
Data.List.Utils is part of the missingh library. If your app can't find it, it is probably not installed. cabal install missingh. To find out where a random import comes from, go to hackage.haskell.org, click on hayoo, and search for "Data.List.Utils". The ambiguous module name is totally different and doesn't happen very often anymore. Monads-fd used to be an improved version of mtl, and it exported roughly the same interface, but monads-fd is now deprecated and shouldn't be used. Sometimes when you load a file it ends up choosing it anyways, because it has to choose something. You can avoid that by typing ghci -hide-package=monads-fd. Alternatively you can use ghc-pkg hide to hide it permanently, so that nothing tries to use that, that should work.
Hi David, Thanks for responding. I'm out here at the hackage.haskell.org site and performed the search. I guess my first question here would be "what is missing"? Does this mean something is missing? I see it for a lot of the components (functions) of Data.List.Utils. Regards, CEO'Riley Charles E. O'Riley Jr. -----Original Message----- From: David McBride [mailto:toad3k@gmail.com] Sent: Tuesday, October 18, 2011 7:38 PM To: ceoriley@gmail.com Cc: beginners@haskell.org Subject: Re: [Haskell-beginners] Data-List-Utils Data.List.Utils is part of the missingh library. If your app can't find it, it is probably not installed. cabal install missingh. To find out where a random import comes from, go to hackage.haskell.org, click on hayoo, and search for "Data.List.Utils". The ambiguous module name is totally different and doesn't happen very often anymore. Monads-fd used to be an improved version of mtl, and it exported roughly the same interface, but monads-fd is now deprecated and shouldn't be used. Sometimes when you load a file it ends up choosing it anyways, because it has to choose something. You can avoid that by typing ghci -hide-package=monads-fd. Alternatively you can use ghc-pkg hide to hide it permanently, so that nothing tries to use that, that should work.
I'm sorry, the name of the library you are missing is called,
coincidentally, "missingH" so, the command 'cabal install missingh'
*should* solve your problem and allow you to build that package. No,
I have no idea why they called it that. Hmm, looked it up, it is a
big library of functions that the author deemed were missing in
haskell. Anyways, it is used quite a bit.
There may be other libraries you are missing, all of which are up on
hackage, and if you aren't sure where a certain import or function
comes from you can look it up in hayoo and get more information about
it.
On Tue, Oct 18, 2011 at 9:15 PM, CEO'Riley
Hi David,
Thanks for responding. I'm out here at the hackage.haskell.org site and performed the search. I guess my first question here would be "what is missing"? Does this mean something is missing? I see it for a lot of the components (functions) of Data.List.Utils.
Regards, CEO'Riley Charles E. O'Riley Jr.
-----Original Message----- From: David McBride [mailto:toad3k@gmail.com] Sent: Tuesday, October 18, 2011 7:38 PM To: ceoriley@gmail.com Cc: beginners@haskell.org Subject: Re: [Haskell-beginners] Data-List-Utils
Data.List.Utils is part of the missingh library. If your app can't find it, it is probably not installed. cabal install missingh.
To find out where a random import comes from, go to hackage.haskell.org, click on hayoo, and search for "Data.List.Utils".
The ambiguous module name is totally different and doesn't happen very often anymore. Monads-fd used to be an improved version of mtl, and it exported roughly the same interface, but monads-fd is now deprecated and shouldn't be used. Sometimes when you load a file it ends up choosing it anyways, because it has to choose something. You can avoid that by typing ghci -hide-package=monads-fd. Alternatively you can use ghc-pkg hide to hide it permanently, so that nothing tries to use that, that should work.
participants (2)
-
CEO'Riley -
David McBride