Issue installing Happy

Question

I'm trying to install Fay. Fay has a dependency on `pretty-show`, so I'm installing that. When I run `cabal install pretty-show`, I get the following error: ``` Resolving dependencies... Configuring pretty-show-1.6.2... cabal: The program happy version >=1.19 is required but the version found at /usr/bin/happy is version 1.18.10 Failed to install pretty-show-1.6.2 cabal: Error: some packages failed to install: pretty-show-1.6.2 failed during the configure step. The exception was: ExitFailure 1 ``` When I try to run `cabal install happy`, it says it's successful: ``` Resolving dependencies... [1 of 1] Compiling Main ( /var/folders/d1/h6lvlvnd0j18lf3ml2rn11dm0000gq/T/happy-1.19.2-89313/happy-1.19.2/Setup.lhs, /var/folders/d1/h6lvlvnd0j18lf3ml2rn11dm0000gq/T/happy-1.19.2-89313/happy-1.19.2/dist/setup/Main.o ) Linking /var/folders/d1/h6lvlvnd0j18lf3ml2rn11dm0000gq/T/happy-1.19.2-89313/happy-1.19.2/dist/setup/setup ... Configuring happy-1.19.2... Building happy-1.19.2... Preprocessing exec…

Accepted Answer

I had this problem once, and in my case it was a version problem.... I had a version of happy that came with the OS (at /usr/bin/happy), but the cabal version was at ~/.cabal/bin/happy.

By the comments in the error message, this might be (is probably?) your problem also.

Check your PATH variable and see if it points to the correct happy.

Issue installing Happy

Solution

Problem