Oh, hi! So you've got a couple of moments to kill and you're looking for something to do? You've come to the right place.
There are sereval ways to find tasks, one is looking in our TODO list. Another is to have a look at the bug reports piled up at the Gentoo Bugzilla. Anything from actually solving the problem to just verify the report or provide more information is helpful.
To start contribute you need a working copy of the haskell overlay, a copy that you can modify and send patches/pull requests from. You could use layman to get a copy, but in this case I'd not recommend it. Assuming you have git emerged, run this to get your own copy of the repo:
git clone https://github.com/gentoo-haskell/gentoo-haskell.git
You need to be able to create patches and send patches/pull requests on github. If you are new to git try to read some basics and drop on freenode://#gentoo-haskell to get help.
We have two kinds of ebuilds, completely manually written, and those mostly generated from hackage using our custom tool hackport.
Ebuilds for complex applications and libraries that take a little more care, like ghc, are written by hand.
The absolutely mostpart though, are projects listed on the hackage site. For all those packages we can generate ebuilds that often only require very little manual tweeking. The dependencies, descriptions etc, written in the .cabal files is used to correctly generate the ebuilds. The progress of hackage and development decisions are important for gentoo haskell, which is why we keep a close cooperation with them.
To get the hackport tool, either install app-portage/hackport-9999 available from the haskell overlay, or get your copy of the repo using
See HOWTO contribute on technical aspects of how to work with overlay.