Re: [Haskell-cafe] Need Control.Monad.State

On 28 July 2010 13:17, michael rice wrote:

See below. Lot's of warnings. Is the install OK? If so, can I use the same *import*?

Yeah, the install is OK. The meaning of the warnings are: * "Warning: -fallow-undecidable-instances is deprecated:" this GHC option has changed name, but the mtl package still uses the old name. * "Warning: Module `Prelude' is deprecated:" mtl doesn't specify any bounds on the version of the base library to be used (mainly because of historic reasons when it wasn't changing much and the Haskell community wasn't stressing versioning as much; note that the last version of mtl was released almost 2 years ago). Because a lot of packages broke when GHC-6.10.4 started shipping with base-4 (along with base-3 for compatability purposes) due to the differences in how exceptions were handled, if there is no upper bound on the version of base to be used then cabal-install plays it safe and uses base-3. However, the next version of GHC (6.14, which should be coming out later this year) will not ship with base-3, so GHC-6.12 included that warning message for people that kept trying to use base-3 that their code won't work with 6.14. So yes, now you can use "import Control.Monad.State".

Michael

--- On Tue, 7/27/10, Ivan Miljenovic wrote:

...

If it isn't installed, you can use cabal-install to install it:

cabal install mtl

-- Ivan Lazar Miljenovic Ivan.Miljenovic@gmail.com IvanMiljenovic.wordpress.com

[michael@localhost ~]$ cabal install mtl Resolving dependencies... Downloading mtl-1.1.0.2... Configuring mtl-1.1.0.2... Preprocessing library mtl-1.1.0.2... Building mtl-1.1.0.2... [ 1 of 21] Compiling Control.Monad.Identity ( Control/Monad/Identity.hs, dist/build/Control/Monad/Identity.o )

Control/Monad/Cont.hs:1:11:     Warning: -fallow-undecidable-instances is deprecated: use -XUndecidableInstances or pragma {-# LANGUAGE UndecidableInstances #-} instead

Control/Monad/Cont/Class.hs:1:11:     Warning: -fallow-undecidable-instances is deprecated: use -XUndecidableInstances or pragma {-# LANGUAGE UndecidableInstances #-} instead

Control/Monad/Error.hs:1:11:     Warning: -fallow-undecidable-instances is deprecated: use -XUndecidableInstances or pragma {-# LANGUAGE UndecidableInstances #-} instead

Control/Monad/Error/Class.hs:1:11:     Warning: -fallow-undecidable-instances is deprecated: use -XUndecidableInstances or pragma {-# LANGUAGE UndecidableInstances #-} instead

Control/Monad/Identity.hs:1:0:     Warning: Module `Prelude' is deprecated:                You are using the old package `base' version 3.x.                Future GHC versions will not support base version 3.x. You                should update your code to use the new base version 4.x.

Control/Monad/List.hs:1:11:     Warning: -fallow-undecidable-instances is deprecated: use -XUndecidableInstances or pragma {-# LANGUAGE UndecidableInstances #-} instead

Control/Monad/RWS/Lazy.hs:1:11:     Warning: -fallow-undecidable-instances is deprecated: use -XUndecidableInstances or pragma {-# LANGUAGE UndecidableInstances #-} instead

Control/Monad/RWS/Strict.hs:1:11:     Warning: -fallow-undecidable-instances is deprecated: use -XUndecidableInstances or pragma {-# LANGUAGE UndecidableInstances #-} instead

Control/Monad/Reader.hs:2:11:     Warning: -fallow-undecidable-instances is deprecated: use -XUndecidableInstances or pragma {-# LANGUAGE UndecidableInstances #-} instead

Control/Monad/Reader/Class.hs:1:11:     Warning: -fallow-undecidable-instances is deprecated: use -XUndecidableInstances or pragma {-# LANGUAGE UndecidableInstances #-} instead

Control/Monad/State/Lazy.hs:1:11:     Warning: -fallow-undecidable-instances is deprecated: use -XUndecidableInstances or pragma {-# LANGUAGE UndecidableInstances #-} instead

Control/Monad/State/Strict.hs:1:11:     Warning: -fallow-undecidable-instances is deprecated: use -XUndecidableInstances or pragma {-# LANGUAGE UndecidableInstances #-} instead

Control/Monad/Writer.hs:1:11:     Warning: -fallow-undecidable-instances is deprecated: use -XUndecidableInstances or pragma {-# LANGUAGE UndecidableInstances #-} instead

Control/Monad/Writer/Class.hs:1:11:     Warning: -fallow-undecidable-instances is deprecated: use -XUndecidableInstances or pragma {-# LANGUAGE UndecidableInstances #-} instead

Control/Monad/Writer/Lazy.hs:1:11:     Warning: -fallow-undecidable-instances is deprecated: use -XUndecidableInstances or pragma {-# LANGUAGE UndecidableInstances #-} instead

Control/Monad/Writer/Strict.hs:1:11:     Warning: -fallow-undecidable-instances is deprecated: use -XUndecidableInstances or pragma {-# LANGUAGE UndecidableInstances #-} instead [ 2 of 21] Compiling Control.Monad.Writer.Class ( Control/Monad/Writer/Class.hs, dist/build/Control/Monad/Writer/Class.o )

Control/Monad/Writer/Class.hs:1:0:     Warning: Module `Prelude' is deprecated:                You are using the old package `base' version 3.x.                Future GHC versions will not support base version 3.x. You                should update your code to use the new base version 4.x. [ 3 of 21] Compiling Control.Monad.Error.Class ( Control/Monad/Error/Class.hs, dist/build/Control/Monad/Error/Class.o )

Control/Monad/Error/Class.hs:1:0:     Warning: Module `Prelude' is deprecated:                You are using the old package `base' version 3.x.                Future GHC versions will not support base version 3.x. You                should update your code to use the new base version 4.x. [ 4 of 21] Compiling Control.Monad.State.Class ( Control/Monad/State/Class.hs, dist/build/Control/Monad/State/Class.o )

Control/Monad/State/Class.hs:1:0:     Warning: Module `Prelude' is deprecated:                You are using the old package `base' version 3.x.                Future GHC versions will not support base version 3.x. You                should update your code to use the new base version 4.x. [ 5 of 21] Compiling Control.Monad.Reader.Class ( Control/Monad/Reader/Class.hs, dist/build/Control/Monad/Reader/Class.o )

Control/Monad/Reader/Class.hs:1:0:     Warning: Module `Prelude' is deprecated:                You are using the old package `base' version 3.x.                Future GHC versions will not support base version 3.x. You                should update your code to use the new base version 4.x. [ 6 of 21] Compiling Control.Monad.RWS.Class ( Control/Monad/RWS/Class.hs, dist/build/Control/Monad/RWS/Class.o )

Control/Monad/RWS/Class.hs:1:0:     Warning: Module `Prelude' is deprecated:                You are using the old package `base' version 3.x.                Future GHC versions will not support base version 3.x. You                should update your code to use the new base version 4.x. [ 7 of 21] Compiling Control.Monad.Trans ( Control/Monad/Trans.hs, dist/build/Control/Monad/Trans.o )

Control/Monad/Trans.hs:1:0:     Warning: Module `Prelude' is deprecated:                You are using the old package `base' version 3.x.                Future GHC versions will not support base version 3.x. You                should update your code to use the new base version 4.x.

Control/Monad/Trans.hs:26:0:     Warning: The import of `System.IO' is redundant                except perhaps to import instances from `System.IO'              To import instances alone, use: import System.IO() [ 8 of 21] Compiling Control.Monad.Cont.Class ( Control/Monad/Cont/Class.hs, dist/build/Control/Monad/Cont/Class.o )

Control/Monad/Cont/Class.hs:1:0:     Warning: Module `Prelude' is deprecated:                You are using the old package `base' version 3.x.                Future GHC versions will not support base version 3.x. You                should update your code to use the new base version 4.x. [ 9 of 21] Compiling Control.Monad.Reader ( Control/Monad/Reader.hs, dist/build/Control/Monad/Reader.o )

Control/Monad/Reader.hs:1:0:     Warning: Module `Prelude' is deprecated:                You are using the old package `base' version 3.x.                Future GHC versions will not support base version 3.x. You                should update your code to use the new base version 4.x. [10 of 21] Compiling Control.Monad.Error ( Control/Monad/Error.hs, dist/build/Control/Monad/Error.o )

Control/Monad/Error.hs:1:0:     Warning: Module `Prelude' is deprecated:                You are using the old package `base' version 3.x.                Future GHC versions will not support base version 3.x. You                should update your code to use the new base version 4.x.

Control/Monad/Error.hs:57:0:     Warning: The import of `Control.Monad.Reader.Class' is redundant                except perhaps to import instances from `Control.Monad.Reader.Class'              To import instances alone, use: import Control.Monad.Reader.Class()

Control/Monad/Error.hs:58:0:     Warning: The import of `Control.Monad.State.Class' is redundant                except perhaps to import instances from `Control.Monad.State.Class'              To import instances alone, use: import Control.Monad.State.Class()

Control/Monad/Error.hs:60:0:     Warning: The import of `Control.Monad.Writer.Class' is redundant                except perhaps to import instances from `Control.Monad.Writer.Class'              To import instances alone, use: import Control.Monad.Writer.Class()

Control/Monad/Error.hs:63:0:     Warning: The import of `System.IO' is redundant                except perhaps to import instances from `System.IO'              To import instances alone, use: import System.IO() [11 of 21] Compiling Control.Monad.List ( Control/Monad/List.hs, dist/build/Control/Monad/List.o )

Control/Monad/List.hs:1:0:     Warning: Module `Prelude' is deprecated:                You are using the old package `base' version 3.x.                Future GHC versions will not support base version 3.x. You                should update your code to use the new base version 4.x. [12 of 21] Compiling Control.Monad.RWS.Lazy ( Control/Monad/RWS/Lazy.hs, dist/build/Control/Monad/RWS/Lazy.o )

Control/Monad/RWS/Lazy.hs:1:0:     Warning: Module `Prelude' is deprecated:                You are using the old package `base' version 3.x.                Future GHC versions will not support base version 3.x. You                should update your code to use the new base version 4.x.

Control/Monad/RWS/Lazy.hs:45:0:     Warning: The import of `Control.Monad.Reader.Class' is redundant                except perhaps to import instances from `Control.Monad.Reader.Class'              To import instances alone, use: import Control.Monad.Reader.Class()

Control/Monad/RWS/Lazy.hs:46:0:     Warning: The import of `Control.Monad.State.Class' is redundant                except perhaps to import instances from `Control.Monad.State.Class'              To import instances alone, use: import Control.Monad.State.Class()

Control/Monad/RWS/Lazy.hs:48:0:     Warning: The import of `Control.Monad.Writer.Class' is redundant                except perhaps to import instances from `Control.Monad.Writer.Class'              To import instances alone, use: import Control.Monad.Writer.Class() [13 of 21] Compiling Control.Monad.RWS ( Control/Monad/RWS.hs, dist/build/Control/Monad/RWS.o )

Control/Monad/RWS.hs:1:0:     Warning: Module `Prelude' is deprecated:                You are using the old package `base' version 3.x.                Future GHC versions will not support base version 3.x. You                should update your code to use the new base version 4.x. [14 of 21] Compiling Control.Monad.RWS.Strict ( Control/Monad/RWS/Strict.hs, dist/build/Control/Monad/RWS/Strict.o )

Control/Monad/RWS/Strict.hs:1:0:     Warning: Module `Prelude' is deprecated:                You are using the old package `base' version 3.x.                Future GHC versions will not support base version 3.x. You                should update your code to use the new base version 4.x.

Control/Monad/RWS/Strict.hs:45:0:     Warning: The import of `Control.Monad.Reader.Class' is redundant                except perhaps to import instances from `Control.Monad.Reader.Class'              To import instances alone, use: import Control.Monad.Reader.Class()

Control/Monad/RWS/Strict.hs:46:0:     Warning: The import of `Control.Monad.State.Class' is redundant                except perhaps to import instances from `Control.Monad.State.Class'              To import instances alone, use: import Control.Monad.State.Class()

Control/Monad/RWS/Strict.hs:48:0:     Warning: The import of `Control.Monad.Writer.Class' is redundant                except perhaps to import instances from `Control.Monad.Writer.Class'              To import instances alone, use: import Control.Monad.Writer.Class() [15 of 21] Compiling Control.Monad.State.Lazy ( Control/Monad/State/Lazy.hs, dist/build/Control/Monad/State/Lazy.o )

Control/Monad/State/Lazy.hs:1:0:     Warning: Module `Prelude' is deprecated:                You are using the old package `base' version 3.x.                Future GHC versions will not support base version 3.x. You                should update your code to use the new base version 4.x. [16 of 21] Compiling Control.Monad.State ( Control/Monad/State.hs, dist/build/Control/Monad/State.o )

Control/Monad/State.hs:1:0:     Warning: Module `Prelude' is deprecated:                You are using the old package `base' version 3.x.                Future GHC versions will not support base version 3.x. You                should update your code to use the new base version 4.x. [17 of 21] Compiling Control.Monad.State.Strict ( Control/Monad/State/Strict.hs, dist/build/Control/Monad/State/Strict.o )

Control/Monad/State/Strict.hs:1:0:     Warning: Module `Prelude' is deprecated:                You are using the old package `base' version 3.x.                Future GHC versions will not support base version 3.x. You                should update your code to use the new base version 4.x. [18 of 21] Compiling Control.Monad.Writer.Lazy ( Control/Monad/Writer/Lazy.hs, dist/build/Control/Monad/Writer/Lazy.o )

Control/Monad/Writer/Lazy.hs:1:0:     Warning: Module `Prelude' is deprecated:                You are using the old package `base' version 3.x.                Future GHC versions will not support base version 3.x. You                should update your code to use the new base version 4.x. [19 of 21] Compiling Control.Monad.Writer ( Control/Monad/Writer.hs, dist/build/Control/Monad/Writer.o )

Control/Monad/Writer.hs:1:0:     Warning: Module `Prelude' is deprecated:                You are using the old package `base' version 3.x.                Future GHC versions will not support base version 3.x. You                should update your code to use the new base version 4.x. [20 of 21] Compiling Control.Monad.Writer.Strict ( Control/Monad/Writer/Strict.hs, dist/build/Control/Monad/Writer/Strict.o )

Control/Monad/Writer/Strict.hs:1:0:     Warning: Module `Prelude' is deprecated:                You are using the old package `base' version 3.x.                Future GHC versions will not support base version 3.x. You                should update your code to use the new base version 4.x. [21 of 21] Compiling Control.Monad.Cont ( Control/Monad/Cont.hs, dist/build/Control/Monad/Cont.o )

Control/Monad/Cont.hs:1:0:     Warning: Module `Prelude' is deprecated:                You are using the old package `base' version 3.x.                Future GHC versions will not support base version 3.x. You                should update your code to use the new base version 4.x. Registering mtl-1.1.0.2... Installing library in /home/michael/.cabal/lib/mtl-1.1.0.2/ghc-6.12.1 Registering mtl-1.1.0.2... [michael@localhost ~]$

-- Ivan Lazar Miljenovic Ivan.Miljenovic@gmail.com IvanMiljenovic.wordpress.com