Haskell cabal-install错误

Question

I am having lots of problems with cabal-install :
1: Every time I do cabal update , it tells me to do cabal install cabal-install , so I do, and then when I do cabal update again, it says the same thing.

2: When I try to install ghc-mod from hackage, it gives me this error:

[username@arch ~]$ cabal install ghc-mod
In order, the following will be installed:
haskell-src-exts-1.14.0 (reinstall) changes: pretty-1.1.1.1 -> 1.1.1.0
hlint-1.8.55 (reinstall)
ghc-mod-3.1.4
setup: The program happy version >=1.17 is required but it could not be found.
ghc-mod-3.1.4 depends on haskell-src-exts-1.14.0 which failed to install.
haskell-src-exts-1.14.0 failed during the configure step.
hlint-1.8.55 depends on haskell-src-exts-1.14.0 which failed to install.

So the problem was The program happy version >=1.17 is required but it could not be found. , so I installed happy 1.19.2 using cabal install happy without problems.

I tried cabal install ghc-mod again, same error, so I tried cabal install haskell-src-exts --reinstall --force-reinstalls . It gave me the following error:

[username@arch ~]$ cabal install haskell-src-exts --reinstall --force-reinstalls
Configuring haskell-src-exts-1.14.0...
setup: The program happy version >=1.17 is required but it could not be found.
Failed to install haskell-src-exts-1.14.0
cabal: Error: some packages failed to install:
haskell-src-exts-1.14.0 failed during the configure step. The exception was:
ExitFailure 1

Basically The program happy version >=1.17 is required but it could not be found. . So happy is the problem again?

I have also tried downloading the tar.gz files from hackage and using cabal install on the .cabal file, also modified the .cabal file to ignore dependencies, still failed.

Answer 1

cabal install places executables in ~/.cabal/bin .

If you add it to your path, you will be able to use the new executables installed by cabal:

$ PATH=$HOME/.cabal/bin:$PATH

Answer 2

I encountered with same problem and I solved the problem with installing happy package(confusing package name). So install it with your package manager(apt-get, pacman etc) before install package with cabal. This should be fix the problem.