Hello, I'm pleased to announce the relase of ghc-vis. This package provides a way to visualize live data structures in GHCi, similar to GHCi's :print and vacuum-cairo. Evaluation is not forced and you can interact with the visualized data structures. This allows seeing Haskell's lazy evaluation and sharing in action. Hopefully it will be useful for teaching Haskell and understanding and debugging data structures. Currently there's a linear view and a graph view using GraphViz. If you want to see some examples of how it looks head to http://felsin9.de/nnis/ghc-vis/ or just give it a try like this: $ cabal install ghc-vis $ echo ":script $HOME/.cabal/share/ghc-vis-0.2.1/ghci" >> ~/.ghci $ ghci GHCi, version 7.4.2: http://www.haskell.org/ghc/ :? for help λ> :vis λ> let a = [1..3] λ> :view a λ> let b = cycle a λ> :view b λ> :view "foo" ++ "bar" λ> :eval t1 λ> :switch On Hackage: http://hackage.haskell.org/package/ghc-vis I'm happy to hear about bugs, feature requests and other thoughts. Dennis