Instantiating sub-class from super
On 16/10/19 6:33 PM, Frank Millman wrote:
> On 2019-10-14 10:55 PM, DL Neil via Python-list wrote:
>> Is there a technique or pattern for taking a (partially-) populated
>> instance of a class, and re-creating it as an instance of one of its
> Here is a link to an article entitled 'Understanding Hidden Subtypes'.
> It dates back to 2004, but I think it is still relevant. It addresses
> precisely the issues that you raise, but from a data-modelling
> perspective, not a programming one.
> I found it invaluable, and applied the concepts in my own
> business/accounting application. Having created the ability to make
> subtypes visible and explicit, I found all kinds of unexpected uses for
> The article seems to be missing a couple of images (Figure 1 and Figure
> 2) showing the data relationships. I downloaded the original article
> onto my computer years ago, and my local copy does have the images, so
> if you would like to see them let me know and I will upload my version
> somewhere to make it accessible.
Yes please Frank - I've also approached it from the data/DB side, and
thus presumably why I was puzzling over how one implements in Python.
(alternatively, email a PDF/similar directly)