Hi

I've run into difficulty building happy and alex using the sandbox feature of cabal-install 1.18.0.2.
Installation of dependencies succeeds but both happy and alex fail with:

    setup: The program happy is required but it could not be found

My workaround is to use the --only-dependencies flag, install the dependencies, and manually install the packages.

This is on Mac OS X 10.8.4 with GHC 7.6.3.

I've copied the steps demonstrating the problem on lpaste:
    http://lpaste.net/95027
Summary to reproduce: cabal sandbox init; cabal install happy alex

Below is the script for my workaround.

[0 :)] badi@olorin /tmp/sb
~> cat sandbox-install.sh
#!/usr/bin/env bash

packages="$@"

cabal sandbox init
cabal install --only-dependencies $packages

for p in $packages; do
    cabal unpack $p
    pushd $p-*
    cabal sandbox --sandbox ../.cabal-sandbox init
    cabal configure
    cabal build
    runhaskell Setup.lhs install
    popd
done

--

Badi' Abdul-Wahid