 <p>There are a large number of things you can do to extend the GHCi prompt. <a href="http://www.haskell.org/haskellwiki/GHC/GHCi" rel="nofollow">This page</a> talks about an old project called GHCi on Acid which suggests a lot of ideas. Generally, by editing your .ghcirc file you can add many command-line call-outs including to tools like commandline lambdabot/hoogle/pointfree.</p>