Hi! The Tree datatype in new Data.Tree module has a Show instance that works like shown below: Prelude Data.Tree> print (Node 'a' [Node 'b' [], Node 'c' []]) - 'a' -+- 'b' | `- 'c' I use a similar module for Trees in conjunction with WASH for generating web pages. WASH session management relies on the ability to read back previously showed values. Writing a Read instance for such Show would be a weird thing to do. I think it would be better to derive Show instance for Tree instead of providing a pretty printing one. Then it would be possible to have a complementing Read instance. The pretty printing function could be provided under a different name (eg. drawTree). The other tiny problem is that the current instance is not recursion-proof: Prelude Data.Tree> let f x = Node x [Node x [], Node x []] Prelude Data.Tree> print (f (f 1)) - - 1 -+- 1 | `- 1 -+- - 1 -+- 1 | `- 1 | `- - 1 -+- 1 | `- 1 Best regards, Tom -- .signature: Too many levels of symbolic links