Building a GHC: setup failed despite successful cabal installation

Question

I am trying to build a GHC from the source following this page . When installing the dependencies, I had to install happyand alex:

$ cabal install alex happy
Resolving dependencies...
Configuring alex-3.2.1...
Configuring happy-1.19.5...
Building happy-1.19.5...
Building alex-3.2.1...
Installed alex-3.2.1
Installed happy-1.19.5

but at startup configure, an error message appears:

$ ./configure
...
checking for happy... no
checking for version of happy... 
configure: error: Happy version 1.19.4 or later is required to compile GHC.

I am running Debian stretch:

$ uname -a 
Linux <host> 4.8.0-1-amd64 #1 SMP Debian 4.8.5-1 (2016-10-28) x86_64 GNU/Linux

Can someone suggest an obvious step that I could try to solve?

Answer 1

I suspect that you simply do not have them on your PATH. Be sure to include something like

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

.bashrc( ). , PATH.

- , , .bashrc, , cabal-install'd .

Answer 2

alex happy Debian. Debian apt-get :

sudo apt-get install alex happy