> The diff is implicit in the difference in tree structure; I can only interpret this as, "the data is not described as diffs." There's a meaningful difference

> The diff is implicit in the difference in tree structure; I can only interpret this as, "the data is not described as diffs." There's a meaningful difference here and I'm not being picky about it. To some extent, you can convert between a diff structure and shared structure, but that doesn't mean that the differences aren't meaningful. Two structures may be isomorphic but they represent data in different ways and the operations have different algorithmic complexity.