travis.ci:

Haskell overlay consists of unstable software, so you'll likely need to keyword everything in it:

# install layman, if you don't have it yet:
emerge layman
layman -f
echo source /var/lib/layman/make.conf >> /etc/portage/make.conf
#
# and the overlay configuration itself:
layman -a haskell
# and unmask unstable versions for your arch:
echo "*/*::haskell ~$(portageq envvar ARCH)" >> /etc/portage/package.accept_keywords

And here is the trick to speed up metadata resolution a bit. If you happen to use eix-sync for rsyncs you might like the following /etc/eix-sync.conf:

*
@egencache --jobs="$(($(nproc) + 1))" --repo=haskell --update --update-use-local-desc

It basically means:

• sync overlays in layman list before the main tree sync
• generate metadata for haskell repo after main tree sync is done, using N+1 cores

Have a nice haskell-related ebuild to share with community? Look at our Developer's README!

Alternatively if you really don't want to share any ebuilds (want to keep outdated package versions, highly experimental things, publically unavailable stuff, other reasons) that's also fine.

You can keep such ebuilds in your local overlay.

Here is a complete example of creating minimal overlay with a single haskell ebuild from hackage:

# create overlay and populate it (gentoo-generic):
$ mkdir my-ovl
$ cd    my-ovl
$ mkdir metadata
$ echo 'masters = gentoo' > metadata/layout.conf
$ echo 'PORTDIR_OVERLAY="'$(pwd) '${PORTDIR_OVERLAY}"' >> /etc/portage/make.conf

# haskell-specific stuff
$ hackport -p . update
# DONE!

# adding an example ebuild
$ hackport merge hichi
$ emerge -av1 hichi