For an example of a Yesod application with Fay integrated, have a look at the
sample/ directory in this repository, or alternatively use the experimental Postgres-Fay (
pf) application template (select it when running
yesod init with recent versions of Yesod).
Usage with cabal sandboxes
You are highly encouraged to create a cabal sandbox for your Yesod app. This feature is available in cabal 1.18+.
Use the following command to set an environment variable (this is a workaround, needed until Fay integrates with haskell-packages, only possible after cabal 1.20 is released).
export HASKELL_PACKAGE_SANDBOX=`echo .cabal-sandbox/*-packages.conf.d/`
Make sure to run this from the root of the Yesod project.