Re: [Haskell-cafe] Curious why "cabal upgrade parsec" not installing latest version

Parsec 3 is unloved by much of the community because it's evidently slower than parsec 2. For this reason the community remains divided over the two versions and cabal has special "preferred versions" of particular packages. To force installation of parsec 3, over the "preferred" parsec 2, you simply execute "cabal install 'parsec >= 3'" Cheers, Thomas On Wed, Sep 15, 2010 at 7:47 PM, Peter Schmitz wrote:

Not that I'm having any problem with parsec 2.1.0.1, but I guess I would like to install the latest (3.1.0), unless there is a reason not to.

I can't seem to get Cabal to do so; thanks in advance for any help.

I don't understand part of the output from "cabal install --dry-run --reinstall -v parsec" at the end below, which includes: "selecting parsec-2.1.0.1 (hackage) and discarding parsec-2.0, 2.1.0.0, 3.0.0, 3.0.1 and 3.1.0".

(http://hackage.haskell.org/package/parsec seems to point to 3.1.0.)

Under Windows XP:

...

H:\proc\dev\cmd>cabal update Downloading the latest package list from hackage.haskell.org

H:\proc\dev\cmd>cabal info parsec * parsec           (library)     Synopsis:      Monadic parser combinators     Latest version available: 3.1.0     Latest version installed: 2.1.0.1     Homepage:      http://www.cs.uu.nl/~daan/parsec.html     Bug reports:   [ Not specified ]     Description:   Parsec is designed from scratch as an industrial-strength                    parser library. It is simple, safe, well documented (on the                    package homepage), has extensive libraries and good error                    messages, and is also fast. It is defined as a monad                    transformer that can be stacked on arbitrary monads, and it                    is also parametric in the input stream type.     Category:      Parsing     License:       BSD3     Author:        Daan Leijen , Paolo Martini     Maintainer:    Derek Elkins     Source repo:   [ Not specified ]     Flags:         base4     Dependencies:  mtl -any, bytestring -any, base >=4 && <5, syb -any,                    base >=3.0.3 && <4     Documentation: [ Not installed ]     Cached:        No     Modules:         Text.ParserCombinators.Parsec         Text.ParserCombinators.Parsec.Char         Text.ParserCombinators.Parsec.Combinator         Text.ParserCombinators.Parsec.Error         Text.ParserCombinators.Parsec.Expr         Text.ParserCombinators.Parsec.Language         Text.ParserCombinators.Parsec.Perm         Text.ParserCombinators.Parsec.Pos         Text.ParserCombinators.Parsec.Prim         Text.ParserCombinators.Parsec.Token

H:\proc\dev\cmd>cabal upgrade parsec Resolving dependencies... No packages to be installed. All the requested packages are already installed. If you want to reinstall anyway then use the --reinstall flag.

H:\proc\dev\cmd>cabal install  --dry-run  --reinstall  parsec Resolving dependencies... In order, the following would be installed (use -v for more details): parsec-2.1.0.1

H:\proc\dev\cmd>cabal install  --dry-run  --reinstall -v  parsec H:\proc\tools\Haskell Platform\2010.1.0.0\bin\ghc.exe --numeric-version looking for package tool: ghc-pkg near compiler in H:\proc\tools\Haskell Platform\2010.1.0.0\bin found package tool in H:\proc\tools\Haskell Platform\2010.1.0.0\bin\ghc-pkg.exe H:\proc\tools\Haskell Platform\2010.1.0.0\bin\ghc-pkg.exe --version H:\proc\tools\Haskell Platform\2010.1.0.0\bin\ghc.exe --supported-languages Reading installed packages... H:\proc\tools\Haskell Platform\2010.1.0.0\bin\ghc-pkg.exe dump --global H:\proc\tools\Haskell Platform\2010.1.0.0\bin\ghc-pkg.exe dump --user Reading available packages... Resolving dependencies... selecting parsec-2.1.0.1 (hackage) and discarding parsec-2.0, 2.1.0.0, 3.0.0, 3.0.1 and 3.1.0 selecting base-3.0.3.2 (installed) and 4.2.0.0 (installed) and discarding syb-0.1.0.0, 0.1.0.1, 0.1.0.2, 0.1.0.3, 0.2 and 0.2.1 selecting ffi-1.0 (installed) selecting ghc-prim-0.2.0.0 (installed) selecting integer-gmp-0.2.0.0 (installed) selecting rts-1.0 (installed) selecting syb-0.1.0.2 (installed) In order, the following would be installed: parsec-2.1.0.1 (reinstall) changes: base-4.2.0.0 -> 3.0.3.2

H:\proc\dev\cmd>

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