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Today's Topics:
1. Question about ghc and cabal: finding packages (C Gosch)
2. Re: Question about ghc and cabal: finding packages
(Mathew de Detrich)
3. Re: Question about ghc and cabal: finding packages
(Henk-Jan van Tuyl)
4. forM vs mapM (Gaius Hammond)
5. Re: forM vs mapM (Thomas Davie)
6. Re: forM vs mapM (Gaius Hammond)
7. Re: Question about ghc and cabal: finding packages
(Jonas Almstr?m Dureg?rd)
8. Re: Question about ghc and cabal: finding packages
(Daniel Fischer)
----------------------------------------------------------------------
Message: 1
Date: Thu, 19 Aug 2010 09:12:49 +0200
From: C Gosch <[email protected]>
Subject: [Haskell-beginners] Question about ghc and cabal: finding
packages
To: [email protected]
Message-ID:
<[email protected]>
Content-Type: text/plain; charset="iso-8859-1"
Hi everyone,
I have installed ghc 6.12.3 and the Haskell platform; now, when I install
packages from hackage using
cabal install <package-name>,
they get installed in ~/.cabal,
which is fair enough.
However, when I call a
runhaskell Setup.lhs configure
that used to work on a different computer with the same software setup,
ghc (or is it cabal?) complains that it cannot find the packages I have just
installed.
Checking again revealed that they are indeed installed, just not in the ghc
installation directory,
but under ~/.cabal.
How can I tell cabal and/or ghc where to look for libraries?
Thanks, again, for any help!
Christian
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Message: 2
Date: Thu, 19 Aug 2010 07:57:50 +0000
From: Mathew de Detrich <[email protected]>
Subject: Re: [Haskell-beginners] Question about ghc and cabal: finding
packages
To: C Gosch <[email protected]>
Cc: [email protected]
Message-ID:
<[email protected]>
Content-Type: text/plain; charset="iso-8859-1"
If you install a package through cabal install, it will automatically
register with GHC (it works the same way that gems works on ruby for
example)
Using runhaskell <commands> is whats used when manually building/configuring
packages (for example creating archlinux packages from cabal packages from
hackage) or when you are developing and creating cabal packages yourself
(in other words, when you do cabal install, cabal internally does all the
commands for configuring/checking dependencies/building and installing)
So you should be able to use use the package instantly after you install it
(you can also use ghc-pkg list to check all installed packages)
On Thu, Aug 19, 2010 at 7:12 AM, C Gosch <[email protected]> wrote:
> Hi everyone,
> I have installed ghc 6.12.3 and the Haskell platform; now, when I install
> packages from hackage using
> cabal install <package-name>,
> they get installed in ~/.cabal,
> which is fair enough.
> However, when I call a
> runhaskell Setup.lhs configure
> that used to work on a different computer with the same software setup,
> ghc (or is it cabal?) complains that it cannot find the packages I have
> just installed.
> Checking again revealed that they are indeed installed, just not in the ghc
> installation directory,
> but under ~/.cabal.
> How can I tell cabal and/or ghc where to look for libraries?
>
> Thanks, again, for any help!
> Christian
>
>
> _______________________________________________
> Beginners mailing list
> [email protected]
> http://www.haskell.org/mailman/listinfo/beginners
>
>
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------------------------------
Message: 3
Date: Thu, 19 Aug 2010 11:06:40 +0200
From: "Henk-Jan van Tuyl" <[email protected]>
Subject: Re: [Haskell-beginners] Question about ghc and cabal: finding
packages
To: [email protected], "C Gosch" <[email protected]>
Message-ID: <[email protected]>
Content-Type: text/plain; charset=iso-8859-15; format=flowed;
delsp=yes
On Thu, 19 Aug 2010 09:12:49 +0200, C Gosch <[email protected]>
wrote:
> Hi everyone,
> I have installed ghc 6.12.3 and the Haskell platform; now, when I install
> packages from hackage using
> cabal install <package-name>,
> they get installed in ~/.cabal,
> which is fair enough.
> However, when I call a
> runhaskell Setup.lhs configure
> that used to work on a different computer with the same software setup,
> ghc (or is it cabal?) complains that it cannot find the packages I have
> just
> installed.
> Checking again revealed that they are indeed installed, just not in the
> ghc
> installation directory,
> but under ~/.cabal.
> How can I tell cabal and/or ghc where to look for libraries?
>
> Thanks, again, for any help!
> Christian
The command "cabal install " installs a package locally by default,
whereas "runhaskell Setup" installs globally. When installing globally,
the local packages are ignored.
Regards,
Henk-Jan van Tuyl
--
http://Van.Tuyl.eu/
http://members.chello.nl/hjgtuyl/tourdemonad.html
--
------------------------------
Message: 4
Date: Thu, 19 Aug 2010 10:02:22 +0000
From: "Gaius Hammond" <[email protected]>
Subject: [Haskell-beginners] forM vs mapM
To: "Haskell Beginners List" <[email protected]>
Message-ID:
<128061004-1282212139-cardhu_decombobulator_blackberry.rim.net-2030406...@bda240.bisx.produk.on.blackberry>
Content-Type: text/plain
Hi all,
Can anyone give me an example of a situation where you would use forM but *not*
mapM or vice versa? As far as I can see one is simply a flip of the other. Does
forM make any guarantees about order of execution?
Thanks,
G
------------------
------------------------------
Message: 5
Date: Thu, 19 Aug 2010 11:08:34 +0100
From: Thomas Davie <[email protected]>
Subject: Re: [Haskell-beginners] forM vs mapM
To: [email protected]
Cc: Haskell Beginners List <[email protected]>
Message-ID: <[email protected]>
Content-Type: text/plain; charset=us-ascii
On 19 Aug 2010, at 11:02, Gaius Hammond wrote:
> Hi all,
>
>
> Can anyone give me an example of a situation where you would use forM but
> *not* mapM or vice versa? As far as I can see one is simply a flip of the
> other. Does forM make any guarantees about order of execution?
Nope, no extra guarentees, just reverses the argument order.
forM can look quite nice if you have a large function that you want to map...
forM [someList]
lots of
large function
here
...
while mapM can look good if you have a small function...
mapM simpleFunction [someList]
They're also useful both ways round partially applied.
Bob
------------------------------
Message: 6
Date: Thu, 19 Aug 2010 10:16:06 +0000
From: "Gaius Hammond" <[email protected]>
Subject: Re: [Haskell-beginners] forM vs mapM
To: "Thomas Davie" <[email protected]>
Cc: Haskell Beginners List <[email protected]>
Message-ID:
<712809430-1282212964-cardhu_decombobulator_blackberry.rim.net-7039081...@bda240.bisx.produk.on.blackberry>
Content-Type: text/plain
Thanks, I suspected that might be the case but it seemed too simple :-)
Cheers,
G
------------------
-----Original Message-----
From: Thomas Davie <[email protected]>
Date: Thu, 19 Aug 2010 11:08:34
To: <[email protected]>
Cc: Haskell Beginners List<[email protected]>
Subject: Re: [Haskell-beginners] forM vs mapM
On 19 Aug 2010, at 11:02, Gaius Hammond wrote:
> Hi all,
>
>
> Can anyone give me an example of a situation where you would use forM but
> *not* mapM or vice versa? As far as I can see one is simply a flip of the
> other. Does forM make any guarantees about order of execution?
Nope, no extra guarentees, just reverses the argument order.
forM can look quite nice if you have a large function that you want to map...
forM [someList]
lots of
large function
here
...
while mapM can look good if you have a small function...
mapM simpleFunction [someList]
They're also useful both ways round partially applied.
Bob
------------------------------
Message: 7
Date: Thu, 19 Aug 2010 13:19:26 +0200
From: Jonas Almstr?m Dureg?rd <[email protected]>
Subject: Re: [Haskell-beginners] Question about ghc and cabal: finding
packages
To: C Gosch <[email protected]>
Cc: [email protected]
Message-ID:
<[email protected]>
Content-Type: text/plain; charset=ISO-8859-1
Try simply
cabal configure
in the directory where Setup.lhs (and your .cabal file) is located.
/J
On 19 August 2010 09:12, C Gosch <[email protected]> wrote:
> Hi everyone,
> I have installed ghc 6.12.3 and the Haskell platform; now, when I install
> packages from hackage using
> cabal install <package-name>,
> they get installed in ~/.cabal,
> which is fair enough.
> However, when I call a
> runhaskell Setup.lhs configure
> that used to work on a different computer with the same software setup,
> ghc (or is it cabal?) complains that it cannot find the packages I have just
> installed.
> Checking again revealed that they are indeed installed, just not in the ghc
> installation directory,
> but under ~/.cabal.
> How can I tell cabal and/or ghc where to look for libraries?
>
> Thanks, again, for any help!
> Christian
>
>
> _______________________________________________
> Beginners mailing list
> [email protected]
> http://www.haskell.org/mailman/listinfo/beginners
>
>
------------------------------
Message: 8
Date: Thu, 19 Aug 2010 14:14:44 +0200
From: Daniel Fischer <[email protected]>
Subject: Re: [Haskell-beginners] Question about ghc and cabal: finding
packages
To: [email protected]
Cc: C Gosch <[email protected]>
Message-ID: <[email protected]>
Content-Type: text/plain; charset="iso-8859-1"
On Thursday 19 August 2010 13:19:26, Jonas Almström Duregård wrote:
> Try simply
>
> cabal configure
>
> in the directory where Setup.lhs (and your .cabal file) is located.
>
> /J
Or, to configure, build and install in one go, just `cabal install' in that
directory.
If you want to go the runhaskell Setup.[l]hs road, however, you have to
pass the --user flag to runhaskell Setup.[l]hs configure if you need
packages from your user db.
Or you have to reinstall the cabal-installed packages globally (surprise:
pass the --global flag to cabal install), perhaps set `user-install: False'
in ~/.cabal/config if you want to have global installs by default.
>
> On 19 August 2010 09:12, C Gosch <[email protected]> wrote:
> > Hi everyone,
> > I have installed ghc 6.12.3 and the Haskell platform; now, when I
> > install packages from hackage using
> > cabal install <package-name>,
> > they get installed in ~/.cabal,
> > which is fair enough.
> > However, when I call a
> > runhaskell Setup.lhs configure
> > that used to work on a different computer with the same software
> > setup, ghc (or is it cabal?) complains that it cannot find the
> > packages I have just installed.
> > Checking again revealed that they are indeed installed, just not in
> > the ghc installation directory,
> > but under ~/.cabal.
> > How can I tell cabal and/or ghc where to look for libraries?
> >
> > Thanks, again, for any help!
> > Christian
> >
------------------------------
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