This is the first skeleton to combine all the building blocks,
and it passes compilation, while of course most of the binding
implementation still needs to be filled in...
It occurred to me, that 90% of this template specialisation
are entirely generic and not dependant on the actual target type.
While the compiler/linker is able to sort such a situation out,
this might lead to template bloat and possibly subtle errors.
So it seems more adequate to emit the generic part of the code
right away from within a dedicated translation unit within the
library module; so the vtable is already in place and only
the flexible part of the code needs to be re-emitted on
each usage site.
- default recommendation is to implement DiffMutable interface
- ability to pick up similar non-virtual method on target
- for anything else client shall provide free function mutatorBinding(subject)
PERSONAL NOTE: this is the first commit after an extended leave,
where I was in hospital to get an abdominal cancer removed.
Right now it looks like surgery was successful.
this is at the core of the integration problem: how do we expose
the ability of some opaque data structure to create a TreeMutator?
The idea is
- to use a marker/capability interface
- to use template specialisation to fabricate an instance of that interface
based on the given access point to the opaque data structure
but unfortunately this runs straight into a tough problem,
which I tried to avoid and circumvent all the time:
At some point, we're bound to reveal the concrete type
of the Mutator -- at least to such an extent that we're
able to determine the size of an allocator buffer.
Moreover, by the design chosen thus far, the active
TreeMutator instance (subclass) is assumed to live within
the top-level of a Stack, which means that we need to
place-construct it into that location. Thus, either
we know the type, or we need to move it into place.
..as concluded from the preceding analysis.
NOTE this entails a semantical change, since this
predicate is now only meant to be indicative, not conclusive
remarks: the actual implementation of the diff application process
as bound via the TreeMutator remains yet to be written...
basically we'll establish a collaboration where both sides
know only the interface (contract) of the partner; a safe margin
for allocation size has to be established through metaprogramming (TODO)
now this feels like making progress again,
even when just writing stubs ;-)
Moreover, it became clear that the "typing" of typed child collections
will always be ad hoc, and thus needs to be ensured on a case by case
base. As a consequence, all mutation primitives must carry the
necessary information for the internal selector to decide if this
primitive is applicable to a given decorator layer. Because
otherwise it is not possible to uphold the concept of a single,
abstracted "source position", where in fact each typed sub-collection
of children (and thus each "onion layer" in the decorator chain)
maintains its own private position
