Im trying to get Agda working following this turtorial. However when I type cabal install agda I get an error saying I have the wrong version of alex installed, I then use cabal install alex and after alex is installed I checks so that alex -v gives me the correct version which it does. I then try to run cabal install agda again but still it is complaining about wrong version of alex. I then put the exact path to alex on my path which is:
/Users/me/Library/Haskell/ghc-7.6.3/lib/alex-3.1.4/bin
This works and fixes the problem for alex but now cabal install agda need the correct version of cpph.
So my questions is why do i need to put ever package directly on my systems path for cabal to find the latest version? Why can it not use the following path which has all the correct symlinks and is also on my systems path:
~/Library/Haskell/bin:
The path ~/Library/Haskell/bin should be the first one in the list of your paths.
Related
I can't understand why it just dosen't work. My question is what might have gone wrong i have created the ~/.bash_profile and tried to add the PATH given by the haskell webpage.
When i preform cabal install i get this output:
Marcuss-MacBook-Pro:~ marcuslagerstedt$ cabal install
cabal: Error reading local package.
Couldn't find .cabal file in: .
Marcuss-MacBook-Pro:~ marcuslagerstedt$
I hope i did a correct question.
But i really need help aswell.
You seem to be wanting to install a particular package, namely agda. The command cabal install takes either the name of a package or assumes you are installing some package in the local directory. You are hitting this second case.
To install agda try:
cabal update
cabal install agda
Hi I've just updated cabal to the latest version by the command
cabal update
and
cabal install cabal-install
Then it returns
Installed cabal-install-1.22.2.0
Updating documentation index /MyPath
I want to use alex and happy. Sorry I'm very new to it.. When I tried to issue alex in ghci by the line
alex wordcount.x
It returns
Not in scope: ‘alex’
Perhaps you meant ‘lex’ (imported from Prelude)
I searched online for this and I found a webpage saying that I should first check the version of them by
cabal configure -v | grep -e alex -e happy
But I got this line
cabal: No cabal file found.
Please create a package description file <pkgname>.cabal
Could anyone help me with this problem?
Once you install cabal you can install other packages.
So, to install the Alex package, you'll do cabal install alex. Then I see that you tried to invoke Alex in GHCi, but that's not correct, since alex is a program. You have to invoke it from the terminal.
I am trying to install Elm and the instructions are to install Haskell and then
sh> cabal update
sh> cabal install cabal-install
sh> cabal install -j Elm elm-repl elm-reactor elm-get
When I do, the cabal-install installation installs text-1.2.0.0 which conflicts with the text-1.1.0.0 which uniplate requires so uniplate and its dependents fail to install. Text-1.1.0.0 is installed and present but is rejected in favour of text-1.2.0.0, even though the target needs text-1.1.0.0.
Is there a way to insist that cabal use text-1.1.0.0?
Is there a way to get text-1.1.0.0 and text-1.2.0.0 to co-exist?
Is there a way to convince uniplate that it can accept text-1.2.0.0?
Or a way to make uniplate (or cabal) believe that version text-1.1.0.0 is actually installed? Would that even work?
When I explicitly try to install version 1.1.0.0 of text, I am told that a reinstall would break other packages. Apparently it is a downgrade and not a co-installation. cabal does not seem to have an option to allow to me install two versions of the same library at the same time.
If I uninstall Haskell and all the libraries and then re-install Elm (without installing cabal-install so I don't get text-1.2.0.0 installed so there is no clash), I get 100 or so lines of
package aeson-0.7.0.4-8f84b14cc682e4c9b009352420076a45 is unusable due to missing or recursive dependencies:
attoparsec-0.10.4.0-ec2d0a330db1f6e3a6a3b79471a403ef hashable-1.2.2.0-45bd22df8c4ead6b3a7fb1d08bb07f7d mtl-2.1.3.1-8bcc0591131896cfc8761a93703d4c61 scientific-0.2.0.2-5e275f5d96527da6dc1f05642692a484 syb-0.4.1-be94ebe67c3607f5df1dfcc1906f5d5c text-1.1.0.0-9bd69e9ace700e05fb08e463086bc383 unordered-containers-0.2.4.0-69836b34d13649bcfacc8fb0c9f53e64 vector-0.10.9.1-c550551354bc7c2b5a1d261f39b2f3f4
package aeson-pretty-0.7.1-5dc26d5a4560afe110e90283479a1251 is unusable due to missing or recursive dependencies:
aeson-0.7.0.4-8f84b14cc682e4c9b009352420076a45
text-1.1.0.0-9bd69e9ace700e05fb08e463086bc383
unordered-containers-0.2.4.0-69836b34d13649bcfacc8fb0c9f53e64
vector-0.10.9.1-c550551354bc7c2b5a1d261f39b2f3f4
package asn1-encoding-0.9.0-94e9066cccf7ead73bee5ae4aa982071 is unusable due to missing or recursive dependencies:
mtl-2.1.3.1-8bcc0591131896cfc8761a93703d4c61
package asn1-parse-0.9.0-af4efc4777a8a0d9d19a626d5e4b08ff is unusable due to missing or recursive dependencies:
asn1-encoding-0.9.0-94e9066cccf7ead73bee5ae4aa982071
mtl-2.1.3.1-8bcc0591131896cfc8761a93703d4c61
text-1.1.0.0-9bd69e9ace700e05fb08e463086bc383
I have no idea at all how in resolve this or where to even try. Has anybody trod this path before and do you have any advice or pointers?
Thank you.
Edit
Installing in a sandbox changes the outcome only by degrees: text-1.1.0.0 does not clash with text-1.1.0.0 but still can not be loaded (despite being installed) and still remains the unsatisfied dependency.
blaze-builder is first to fail with cannot satisfy -package-id text-1.1.0.0-9bd69e9ace700e05fb08e463086bc383 yet the same log earlier stated [_12] trying: text-1.1.0.0/installed-9bd... (dependency of Elm-0.13) without apparent error or complaint.
cabal list shows both text-1.1.0.0 and text-1.2.0.0 as installed.
Installing blaze-builder separately looks the same. Dependency resolution shows
[_56] trying: blaze-builder-0.3.3.4 (user goal)
[_57] next goal: text (dependency of blaze-builder-0.3.3.4)
[_57] trying: text-1.1.0.0/installed-9bd...
[_58] done
All looks good but later, same log has
<command line>: cannot satisfy -package-id text-1.1.0.0-9bd69e9ace700e05fb08e463086bc383
(use -v for more information)
The ghc command line already had the -v flag and trying to re-run the command line copied from the log, with more -vs, gives an error with "can't find a package database at
dist/dist-sandbox-ad0bcd57/package.conf.inplace".
No package.conf.inplace seems to exist.
Further edit
On the Elm install page is a link to a BuildFromSource.hs script that is also supposed to work installing Elm. In the time that it took for that script to run and fail to work, I managed to install leiningen, node, npm, grunt and Clojure. I am now further along the road to getting Clojurescript installed in about 20 minutes than I am in getting Elm installed in nearly a week.
Elm looked really interesting but it is playing way too hard to get.
Thanks again to everyone who tried to help.
* Edit *
I finally got it.
Every executable installed by the installer at http://elm-lang.org/Install.elm caused a segfault.
The "Build from source" option at the same page did not work because the dependencies either stepped all over each other or could not get themselves straight in the first place.
The ghc at http://new-www.haskell.org/downloads/osx needs a later version of Mac OS than I have. (A link to older versions would not have gone astray.)
The solution (and it is obvious in retrospect) was to port install haskell-platform and port install hs-cabal-install and cabal install Elm .... I did have to run one of those installers twice because it could not find hackage.haskell.org (How is that a 'user' error?) but my hello-world.elm now compiles.
Thank you all again.
It looks like some dependency issues with elements you already have installed. You will probably need to install it in a sandbox.
First, update to the latest version of cabal:
$ cabal update
$ cabal install cabal cabal-install
Next, make sure you have the installed version of cabal on your $PATH.
$ which cabal
> /path/to/cabal/bin/cabal
If it says something like /usr/bin/cabal you will need to export cabal to be on your $PATH. For me this is `/home/username/.cabal/bin
$ export PATH=/path/to/cabal/bin/cabal;$PATH
Run which cabal again and ensure it is pointing to that path.
Now that you have the latest version of cabal. Run the following:
$ mkdir elm
$ cd elm
$ cabal sandbox init
This will initialize a sandbox where dependencies are completely independent of your other installs. Within this directory, you should be able to install the elm platform by running:
$ cabal install Elm elm-repl elm-reactor elm-get
These will be installed in a sub-directory called .cabal-sanbox/bin/ For convenience, you will probably want to add this to your $PATH so you can run the executables from any directory.
Hope this helps!
When I tried to load a .hs in ghci, it failed on the line:
import System.Random
Message:
Could not find module `System.Random'
Use -v to see a list of the files searched for.
I remember it worked yesterday and all of a sudden today it does not work.
This problem only occurs on Ubuntu 12.04 LTS, GHCi 7.4.1 , when i tried this on windows haskell platform and other linux machines i worked.
I tried to use
sudo apt-get remove ghc
sudo apt-get install ghc
to remove and re install ghc, but however the problem persists.
Could someone help me? Thanks
You must install the random package. You can probably get it from your package manager (as something like libghc-random-dev or similar), or you may cabal install random.
Edit in 2021 These days, cabal install is not the way. Instead, use cabal init to create a package and list random in your build-depends field. Compilation can be performed with cabal build (just build) or cabal run (to execute the result); interactive use is available via cabal repl.
So, this is a bit of a personal problem, but maybe people will have good advice or workarounds.
The problem is about installing cabal-install and haskell-platform under Debian.
When you apt-get install haskell-platform, it ships with cabal-install, and its command cabal is available.
Now this cabal-install is not up-to-date:
> which cabal
/usr/bin/cabal
> /usr/bin/cabal --version
cabal-install version 0.8.0
using version 1.8.0.2 of the Cabal library
But, my understanding of running cabal update is that it updates cabal, but since it is not a "Debian thingy", it puts it in ~/.cabal/bin/.
> ~/.cabal/bin/cabal --version
cabal-install version 0.8.2
using version 1.8.0.2 of the Cabal library
Now my system has 2 cabals, and the one I get by typing cabal is not the one I want to use... Because it'll keep updating the other one instead of itself, and is therefore ineffective.
So what I did was I aliased it in my ~/.bashrc:
alias cabal='~/.cabal/bin/cabal'
Now:
> cabal --version
cabal-install version 0.8.2
using version 1.8.0.2 of the Cabal library
So, my final questions:
Is there a deb repository that holds cabal 0.8.2?
Could my current solution lead to problems? (For instance, which cabal still points to my useless /usr/bin/cabal, so if scripts use this command they'll get fooled...)
Did someone come up with a better solution? (Mine is a bit ad-hoc but that's all I could come up to with my poor knowledge of what is happening behind the scenes...)
Please correct me if anything I say above is wrong or inaccurate.
What I do is installing cabal with the --global flag. This will install cabal into /usr/local/bin/cabal, thus it will always superseed the Debian packages cabal.
Another way, is to generally avoid the Debian packages and install the Haskell platform straight from its source. This approach is also better, if you always want to have the latest releases of the Haskell libs.
I keep my user-local $HOME/.cabal/bin in the front of the PATH.
I install only ghc6, ghc6-prof, ghc6-doc and cabal-install from the distribution packages. I don't use distribution cabal-install for anything more than to bootstrap the new ~/.cabal.
All the rest I install with cabal install, including the newer cabal itself.
When I want to use newer GHC, I deploy it in /usr/local/stow/ghcVERSION, and enable it with GNU stow (it adds symlinks in /usr/local which, again, has precedence in my PATH). When I want to switch back to the distribution GHC I just run stow -D to remove all symbolic links to it.
I consider using cabal-dev to have project-specific cabal installations, and avoid broken dependencies which happen with cabal from time to time.
As a matter of fact I don't use Haskell Platform at all because I don't need all of it and find it easier to be able to install individual libraries. I do not install distribution libraries, because not all of them are available or are exactly the versions I need; and it is much easier to control conflicts if all of them are installed in the same place (~/.cabal in my case). I do not install anything with --global, because I think it is wrong and difficult to rollback.
Of course this information gets out of date, but yes, Debian unstable and testing have, at the time of writing, cabal-install 0.10.2.
Generally, the Debian packaging of Haskell stuff is aimed at users who want a set of packages that is known to work together, i.e. no dependency hell, at the expense of not always having the latest and greatest. This includes cabal-install. I use cabal-install from the repositories, and only to install those libraries that have not been packaged for Debian yet.
Disclaimer: I am one of the guys that create those packages for Debian.
On Ubuntu I also tend to install GHC via stow, ignoring the system packages altogether.
One slight twist from jetxee's approach is that I do install the Haskell Platform (from source), lumping it in with the GHC stow directory. I suppose I ought to call the paths /usr/local/stow/haskell-platform-VERSION, but I tend to use /usr/local/stow/ghc-VERSION instead.