On Wed, Mar 6, 2019 at 4:01 PM Chris Angelico wrote:
> On Thu, Mar 7, 2019 at 10:52 AM Josh Rosenberg
> wrote:
> >
> > Allowing dicts to get involved in + means:
>
> Lots of words that basically say: Stuff wouldn't be perfectly pure.
>
> But adding dictionaries is fundamentally *useful*. It is
len(dict1 + dict2) does not equal len(dict1) + len(dict2), so using the +
operator is nonsense.
len(dict1 + dict2) cannot even be computed by any expression involving +.
Using len() to test the semantics of the operation is not arbitrary; the
fact that the sizes do not add is a defining quality
