#1463: Module → Package lookup in ghc-pkg?
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Reporter: [EMAIL PROTECTED] | Owner:
Type: feature request | Status: new
Priority: normal | Milestone: 6.10
Component: Compiler | Version: 6.6.1
Severity: normal | Resolution:
Keywords: | Difficulty: Unknown
Os: Unknown | Testcase:
Architecture: Unknown |
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Changes (by simonmar):
* milestone: => 6.10
Comment:
in fact, i thought it should be one of the things cabal ought to be good
at, but
looking through the haddocks for Distribution.*, i seem to be running
around in
circles: is there any standard way to get at the installed package.conf
files, or
directly at the InstalledPackageInfos?? there's a getInstalledPackages,
but that only
gives me the PackageIdentifiers?, with no obvious way to go further?
This is parly by design. Cabal interacts with the package database only
using the `ghc-pkg` tool (`hc-pkg` in general), the idea being that the
representation and location of the package database can be compiler-
dependent. There's no requirement that the package database is stored in
the way that GHC does it, or even that the package database contains
`InstalledPackageInfo`s - a compiler might want to add extra information
about each package. In fact, GHC already has an alternative way to store
the package database (files in `package.conf.d`).
To get an `InstalledPackageInfo` for a given package, you have to use
`ghc-pkg describe` and parse the output (I believe it should work).
Parsing `package.conf` directly is non-portable, and risks breakage in the
future. We could add a way to get the `Read/Show` version of an
`InstalledPackageInfo`, if that would make it easier.
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/1463>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler
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