This uses the format for LF values that we already use elsewhere.
There is one annoying part in this PR where I had to duplicate the
logic for converting to the types used in the interface reader since
it is not exposed but hopefully we can get rid of this soon in a
separate PR.
fixes#3470
The code still needs a fair amount of cleanup but it seems to work and
there is a test so I’d like to do the cleanup in-tree after merging
the current state
