On 6/18/19 1:25 PM, Stephen J. Turnbull wrote:
> Dan Sommers writes:
>
> > How would I "think of types as collections of their instances"?
>
> The canonical example of a type as a collection of instances is an
> enumeration, the simplest (useful) example of which is bool = {False,
> True}.
And now the light goes on. :-)
[...]
> > In my mind, a type is a description/container/shortand for a
> > collection of properties or behaviors of instances of that type.
>
> That's one way to think about it, of course. But the strong
> intuitions about the numeric tower (a natural number *is* an integer,
> an integer *is* a real number, and so on) as well as some useful but
> (intuitively) more artificial ideas such as a bool *is* a natural
> number are just as well expressed as set inclusions. This is useful
> in type theory, but explaining "how" is way beyond the scope of this
> post (and this whole list, in fact).
Thanks, Stephen; you've done just enough to give me a good shove in the
right direction.
_______________________________________________
Python-ideas mailing list -- [email protected]
To unsubscribe send an email to [email protected]
https://mail.python.org/mailman3/lists/python-ideas.python.org/
Message archived at
https://mail.python.org/archives/list/[email protected]/message/P7C4WEPJQLZAYFFXRNK2CJOCNWZBEX44/
Code of Conduct: http://python.org/psf/codeofconduct/
