ghc/haskell tool registry

Christian Maeder Christian.Maeder at
Tue Nov 20 03:48:52 EST 2007


registry sounds like overkill to me. If really an absolute hardcoded
path is needed, I would appreciate if it is stored only in a single
place (for ghc, ghci, ghc-pkg and package.conf).

Other tools have a "relocate" script, that only changes that location
after unpacking (or move).

Cheers Christian

Claus Reinke wrote:
> may i suggest a different approach? most shells have commands to list
> programs in PATH beyond the first match, such as 'whereis ssh', 'which
> -a ssh', or 'type -a ssh'. now, this won't
> help directly because the ghc tool in question might not be on
> the PATH.
> but as this issue is so widespread, one could extend one of the
> existing haskell package registries (ghc-pkg, cabal) to cover
> haskell tools as well. every haskell tool would know how to
> register itself with its current location, and how to query the haskell
> tool registry for the location of other tools (preferably from the same
> build/version). since we're on the ghc list:
>    ghc-tools (un-)register <path>/ghc<version>
>    ghc-tools list ghc<version>
>    ghc-tools describe runhaskell
>    ghc-tools field location ghc-6.9
>    ghc-tools field user_guide ghc-6.9
>    ..
> pros:
>    - knowing your version would be sufficient to find
>        all the tools from your bundle
>    - finding all available haskell tools would be easy
> downsides:
>    - tools would have to register themselves after
>        installation/relocation, and unregister during        uninstall
>    - there is no single ghc-pkg/cabal instance to choose,
>        but multiple versions..
> the former is no worse than for packages, the latter
> is a runhaskell-style issue: we want a single ghc-tools
> in the path, but we don't care who provides it.
> claus
> ----- Original Message ----- From: "Simon Marlow"
> <simonmarhaskell at>
> To: "Christian Maeder" <Christian.Maeder at>
> Cc: "Manuel M T Chakravarty" <chak at>; "GHC List"
> <glasgow-haskell-users at>
> Sent: Monday, November 19, 2007 9:35 AM
> Subject: Re: GHC 6.8.1 on Mac OS X 10.5 (Leopard)
>> Christian Maeder wrote:
>>> Ian Lynagh wrote:
>>>> On Sat, Nov 17, 2007 at 03:02:55PM +0000, C.M.Brown wrote:
>>>>>> Is there a way for GHC on OS X to find where it was run from, so
>>>>>> that it
>>>>>> can find package.conf?
>>>>> The command:
>>>>> ghc --print-libdir
>>>>> should do it.
>>>> But the way that knows what to print on unix machines is that ghc is a
>>>> shell script wrapper which passes -B<libdir> to the real GHC binary. If
>>>> you want to be able to move GHC around then the wrapper can't have the
>>>> path hardcoded.
>>> The wrapper could call `pwd` to find out the current path.
>> pwd gives you the directory that the script was invoked *from*, not
>> the directory in which the script resides.  This is a common problem
>> on Unix: there's no general way to find out the location of a binary.
>> Well that's not entirely true.  On Linux you have /proc/<pid>/exe, and
>> on Solaris you have getexecname().  Does MacOS X have anything?
>> Cheers,
>> Simon
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