> 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`.

grepping a tree would not be hard. You simply go down to the leaves and "grep" on the properties themselves. Inversely, structured data lets you easily get to a property.

For example, if you grep the output ls -l for a file named "1", you'll also get files with 1 in their timestamp. In text land, you have to edit the ls command to get simpler output. In structured land, you could edit your filter: ls -l | grep name~=1

You could imagine various structured data filter tools that could be built that wouldn't require modifying the input.

Though in this example, you can easily use awk to select the column, wouldn't it be nice to not have to worry about things like escape characters when parsing text?