> Typed objects can make it harder to pipe commands together. How do you grep a tree when tree is an actual data structure and grep expects a list of items as input? You would need to have converters. Either specific converter between tree and list, or a generic one: tree->text->list.

To be fair, untyped objects also require converters, but at every boundary. That is, instead of having some pipes of the form `program -> mutually agreeable data structure -> program` and some pipes of the form `program -> unacceptable data structure -> parser -> program` (as happens with a typed language), you are guaranteed by a text-based interface always to have pipes of the form `program -> deparser -> text -> parser -> program`.