你是否在寻找Text.PrettyPrint? http://www.haskell.org/haskellwiki/Applications_and_libraries/Compiler_tools#Pretty_printing
vacuum
来可视化抽象语法树:http://www.reddit.com/r/haskell/comments/87v5v/use_vacuum_to_graph_your_heap/ 和 http://www.youtube.com/watch?v=X4-212uMgy8。 - max taldykin