This removes the assertions that checked plugin devs didn't do anything
overly bad in favour of using mypy to ensure appropriate type-checking.
It also moves the ProgressCallback typing information to constants in
order to avoid circular imports (since constants doesn't import
anything).
Relented on the strict import of direct objects/classes for the typing
module only. Typing module components can be directly imported because
it makes the code really painful to read and write otherwise.
This is still in-line with the python style guide adopted from Google at
http://google.github.io/styleguide/pyguide.html section 2.2.
Note: also remove interfaces_configuration where ever possible
(this is not possible in the interfaces directory itself
because it would cause an import loop).
They weren't consistent and they show just remind me how slowly
I've been getting vol 3 written! 5:S
There's git commits to track all of that stuff if we need it.
This template type allows objects that have not been able to be resolved
to exist within the symbol system. It emits a debug message on creation
so that intermediate format developers can identify potential issues,
but does not raise an exception so as to allow partial tables to be
used.
If the UnresolvedTemplate is called (to create an object) before the
symbol has been added to the symbolspace, it will fail with a
SymbolError (as thrown by the individual SymbolTable). For this reason,
the class has been made private to the SymbolSpace class to prevent
unexpected use.
Mike Auty