`PreBasis` is a tree, but does not implement the TypeTree interface
I just observed, that, althought a PreBasis
forms a tree, it does nt derive from any of the dune-typetree nodes. Instead it defines internally the Node
typedef, which is a node around an other PreBasis
(in the case of nested structures.)
I seems that this construction makes a somewhat harder to apply tree transformations to a PreBasis
. Is there a articular reason? I stumbled over this while trying to implement a typetree conversion from a PreBasis
to the appropriate ISTL vector type in PDELab.