I have a Haskell package that is built and installed with Cabal. Running cabal repl in the package directory works perfectly, all the module imports work, etc. When I try to use the package in another directory, imports do not complain, but when I try to use a function from the file, I get this error in GHCi
λ> import Data.Frame
λ> import Data.Frame.CSV
λ> :t fromCsvHeaders
/Users/Stian/.cabal/lib/x86_64-osx-ghc-7.8.3/frame-0.1.0.0/Data/Frame/CSV.dyn_hi
Declaration for fromCsvHeaders:
Failed to load interface for ‘Data.Frame.Internal’
Perhaps you haven't installed the "dyn" libraries for package ‘frame-0.1.0.0’?
Use -v to see a list of the files searched for.
Cannot continue after interface file error
The same happens when running ghc.
Turns out in this case there was an internal module that had not been exposed in the cabal file.
Related
Am working through Real World Haskell and am trying to install regex-posix-0.95.2 from an untar[ed] package by simplying running
cabal install
I then see:
Text/Regex/Posix/Wrap.hsc:141:1: error:
Could not find module ‘Text.Regex.Base.RegexLike’
There are files missing in the ‘regex-base-0.93.2’ package,
try running 'ghc-pkg check'.
Use -v to see a list of the files searched for.
|
141 | import Text.Regex.Base.RegexLike(RegexOptions(..),RegexMaker(..),RegexContext(..),MatchArray)
Despite the fact that I can load this in ghci with
Prelude> :module Text.Regex.Base.RegexLike
Prelude Text.Regex.Base.RegexLike>
Prelude> import Text.Regex.Base.RegexLike(RegexOptions(..),RegexMaker(..),RegexContext(..),MatchArray)
Prelude Text.Regex.Base.RegexLike>
and see it in the module-system.
[warrick#warrick-pc regex-posix-0.95.2]$ ghc-pkg find-module Text.Regex.Base.RegexLike
/usr/lib/ghc-8.6.2/package.conf.d
regex-base-0.93.2
Why is this failing?
What are some more general tips and tricks when trying to debug cabal failures you'd recommend (as this is one instance of many issues I'm consistently having with Cabal)?
This is a linking issue. For example, some distributions like Arch use dynamic linking by default, without static libraries, but without additional configuration, cabal tries to link statically, which results in the kind of message you are seeing. For more information: https://wiki.archlinux.org/index.php/Haskell
I have been trying to run a simple Haskell program using TDFA. The program is as follows:
import Control.Monad
import Data.Array
import qualified Data.Text as T
import Text.Regex
import Text.Regex.TDFA
import Text.Regex.Base
str = "abbbbaab" :: String
regex = "(a+)(b+)" :: String
main = do
if str (=~) :: regex then putStrLn "matched" else putStrLn "no matches"
when I try to run the above program using the command like: ghc test.hs -o test and then I am getting the following error (test.hs is the Haskell program which contains the above code):
Text/Regex/TDFA/NewDFA/Engine.hs:13:33: parse error on input ‘#’
Note that I have the latest version of TDFA installed on my pc. I did it by following ways:
ghc --make -o setup Setup.hs
Also, I did the following:
user#user-VirtualBox:~/regex-tdfa-master$ sudo cabal install regex-tdfa
[sudo] password for user:
Resolving dependencies...
All the requested packages are already installed:
regex-tdfa-1.2.2
Use --reinstall if you want to reinstall anyway.
I even tried it with the Makefile which I got from TDFA's github repository:
user#user-VirtualBox:~/regex-tdfa-master$ make
ghc -o setup --make ./Setup.hs
./setup clean
cleaning...
./setup configure --prefix=/Users/user/local/devel/trl --enable-library-profiling --user
Configuring regex-tdfa-1.2.2...
./setup build
Building regex-tdfa-1.2.2...
Preprocessing` library regex-tdfa-1.2.2...
[ 1 of 23] Compiling Text.Regex.TDFA.NewDFA.Uncons ( Text/Regex/TDFA/NewDFA/Uncons.hs, dist/build/Text/Regex/TDFA/NewDFA/Uncons.o )
...........(Skipped to make the things short here)..............................
[23 of 23] Compiling Text.Regex.TDFA ( Text/Regex/TDFA.hs, dist/build/Text/Regex/TDFA.o )
Text/Regex/TDFA.hs:60:8:
Could not find module ‘Text.Regex.Base’
Perhaps you haven't installed the profiling libraries for package ‘regex-base-0.93.2#regex_47KXx9dLqeO8MNJeizLKhP’?
Use -v to see a list of the files searched for.
Text/Regex/TDFA/ByteString.hs:24:8:
Could not find module ‘Text.Regex.Base.Impl’
Perhaps you haven't installed the profiling libraries for package ‘regex-base-0.93.2#regex_47KXx9dLqeO8MNJeizLKhP’?
Use -v to see a list of the files searched for.
Text/Regex/TDFA/CorePattern.hs:37:8:
Could not find module ‘Control.Monad.RWS’
Perhaps you haven't installed the profiling libraries for package ‘mtl-2.2.1#mtl_Aue4leSeVkpKLsfHIV51E8’?
Use -v to see a list of the files searched for.
Text/Regex/TDFA/ReadRegex.hs:13:8:
`Could not find module ‘Text.ParserCombinators.Parsec’`
Perhaps you haven't installed the profiling libraries for package ‘parsec-3.1.9#parse_EE5NO1mlYLh4J8mgDEshNv’?
Use -v to see a list of the files searched for.
Text/Regex/TDFA/String.hs:23:8:
Could not find module ‘Text.Regex.Base.RegexLike’`
Perhaps you haven't installed the profiling libraries for package ‘regex-base-0.93.2#regex_47KXx9dLqeO8MNJeizLKhP’?
Use -v to see a list of the files searched for.
Text/Regex/TDFA/TDFA.hs:10:8:`
Could not find module ‘Control.Monad.State’
Perhaps you haven't installed the profiling libraries for package ‘mtl-2.2.1#mtl_Aue4leSeVkpKLsfHIV51E8’?
Use -v to see a list of the files searched for.
Makefile:16: recipe for target 'build' failed
make: *** [build] Error 1
user#user-VirtualBox:~/regex-tdfa-master$
However, nothing worked. Hence, any help would be so appreciated...
Text/Regex/TDFA/NewDFA/Engine.hs:13:33: parse error on input ‘#’
On an initial note, this error points to a module of the regex-tdfa package, so you should have gotten it when building the package, rather than when building your test.hs, unless you were trying to build test.hs after putting it within the package source tree. In any case, line 13 of the mentioned file is:
import GHC.Prim(MutableByteArray#,RealWorld,Int#,sizeofMutableByteArray#,unsafeCoerce#)
The # names require the MagicHash GHC extension to be enabled. As there is no {-# LANGUAGE MagicHash #-} pragma at the beginning of the file, one should assume the extension is enabled through the .cabal file of the package, and that is indeed the case. That being so, your problem seems to be that you are attempting use the package modules straight from the source tree, without using an appropriate build tool such as Cabal. (Note that if you did successfully run cabal install regex-tdfa there should be no need of dealing with the source tree: ghc --make -o test test.hs should be enough.)
P.S.: There is an error in your test.hs. The last line should be...
if str =~ regex then putStrLn "matched" else putStrLn "no matches"
(I did manage to run it after this correction.)
It looks like you are compiling your program from within Regex-TDFA source code. I am able to reproduce your problem if I do cabal unpack regex-tdfa && cd regex-tdfa-1.2.2 && ghc --make test.hs.
The error happens because when GHC finds Regex-TDFA source files in the current directory, it just picks them and tries to compile, as if they were ordinary source files belonging to your project. However, Regex-TDFA cannot be built with simple ghc --make: in order to build it, you have to run cabal first. Cabal will read regex-tdfa.cabal file that contains the list of the necessary GHC extensions.
In particular, parse error happens because GHC extension MagicHash is missing (that's where the hash # comes from).
The "fix" is to move your test.hs to some other location: then GHC will use system package for Regex-TDFA.
I tried using the primes module in Haskell and after running
$ cabal install primes
Resolving dependencies...
Notice: installing into a sandbox located at /home/christoph/.cabal-sandbox
Downloading primes-0.2.1.0...
Configuring primes-0.2.1.0...
Building primes-0.2.1.0...
Installed primes-0.2.1.0
I tried making a file with
import Data.Numbers.Primes
at the top, but every attempt to load it failed with the error message:
Could not find module ‘Data.Numbers.Primes’
Use -v to see a list of the files searched for.
The question: what am I missing here? there must be something wrong with this way of using it right?
After reading Haskell: where is Data.Numbers.Primes library? I also tried:
import Data.Primes
import primes
import Primes
but none of them worked.
Thank you in advance, any help is most welcome
Because you are installing the primes package to a sandbox, you will need to run the compiler with awareness of the sandbox. cabal offers the exec command for this, so e.g.
echo import Data.Numbers.Primes >foo.hs
cabal exec ghci foo.hs
from within the sandbox should work.
I tried importing Data.Numbers.Primes
import Data.Numbers.Primes
runhaskell gave me:
5.hs:1:8:
Could not find module `Data.Numbers.Primes'
Use -v to see a list of the files searched for.
ghci gave me:
<no location info>:
Could not find module `Data.Numbers.Primes'
It is not a module in the current program, or in any known package.
I tried to install Data.Numbers.Primes through cabal, but I got:
cabal update
...
cabal install Data
cabal: There is no package named 'Data'.
You may need to run 'cabal update' to get the latest list of available
packages.
cabal install Data.Numbers.Primes
cabal: The file does not exist 'Data.Numbers.Primes'.
help?
The package you're looking for is called primes.
There's no rule that the package will be called the same as its top-level module name. Typically, packages put themselves under whatever makes sense, but that's pretty much arbitrary. When in doubt, Hackage search helps.
I'm working on a project and I'm using Cabal for management. I've specified directory of source files, modules, all the stuff. All my files have the same names as their corresponding modules, case is preserved.
I can do:
$ cabal configure
$ cabal build
without problems.
However, imagine I have a module Module in file Module.hs, and file File.hs in the same directory. Now, when I'm trying to load File.hs from Emacs for testing, I get the following:
____Could not find module ‘Module’
It is a member of the hidden package ‘ghc-7.8.3’.
Use -v to see a list of the files searched for.
Failed, modules loaded: none.
Full contents of File.hs:
module File where
import Module
How to make it find files of my project?
You can launch the REPL via Cabal like so:
# cabal repl
This is the same as running ghci, but will take into account any additional dependencies installed by cabal install your local or sandbox package repository.
You need to tell GHCi where to find your source files. For example, if your project directory is ./foo and you have your source files in ./foo/src you need to say (from your project directory):
:set -isrc
at the command prompt in GHCi. You will then have access to private members in your sourc file loaded with C-c C-l.
You also need to make sure that you haven't cabal installed your package, otherwise the package will be loaded, not the project source files.
I had the same problem, fixed it, and decided to write about my troubleshooting. This might help new people learning Haskell. Read on.
I was playing around with this example code.
http://zvon.org/other/haskell/Outputdirectory/getCurrentDirectory_f.html
Code:
import Directory
main = aaa "/tmp/FOO"
aaa ddd = do createDirectory ddd
setCurrentDirectory ddd
d <- getCurrentDirectory
print d
writeFile "aaa" "HELLO"
l <- getDirectoryContents d
print l
I noticed that they are using this package.
https://hackage.haskell.org/package/directory-1.3.6.2/docs/System-Directory.html
So I installed it with this commands:
cabal update
cabal install directory
Compiling the example code with ghc failed with this error message.
Could not find module `Directory'
Use -v to see a list of the files searched for.
|
4 | import Directory
| ^^^^^^^^^^^^^^^^
I was stuck for a while until I changed the import line to this:
import System.Directory
After this change ghc could compile successfully.
Conclussion: are you sure you are importing properly?