GitLab

There still exists the TreePath template for encoding a fully static path. Conceptually this was superseded by HybridTreePath since HybridTreePath<index_constant<i>...> can serve the same purpose as TreePath<i...>. Hence I think it's a good idea to get rid of TreePath. Also TreePath itself is no longer used in dune-typetree. But there's two main obstacles:

• You cannot use HybridTreePath<index_constant<i>...> because a lot of the utility functions for TreePath are not implemented for HybridTreePath. This is mostly because the intended use is different: HybridTreePath is intended to by used as value, while those utilities act on types only.
• Dune-pdelab still uses TreePath in many places.

In principle I solved both locally:

• Implement (in dune-typetree) the missing utilities to make HybridTreePath<index_constant<i>...> a drop in replacement for TreePath<i...>.
• Replace (in dune-pdelab) all uses of TreePath by the corresponding HybridTreePath

Is there interest (from pdelab) in this change? In the long run I think that many of the above mentioned utilities can/should be dropped if pdelab switches to a more value based handling of treepaths.