Re: [Python-ideas] Type Hinting Kick-off

On Wed, Dec 24, 2014 at 08:16:52PM -0800, Guido van Rossum wrote:

On Wed, Dec 24, 2014 at 4:50 PM, Eugene Toder wrote: [...]

...

Pragmatics:

3. The names Union and Intersection are standard terminology in type checking, but may not be familiar to many Python users. Names like AnyOf[] and AllOf[] can be more intuitive.

I strongly disagree with this. Python's predecessor, ABC, used a number of non-standard terms for common programming language concepts, for similar reasons. But the net effect was just that it looked weird to anyone familiar with other languages, and for the users who were a completely blank slate, well, "HOW-TO" was just as much jargon that they had to learn as "procedure". Also, the Python users who will most likely need to learn about this stuff are most likely library developers.

I presume that runtime name binding will be allowed, e.g. from typing import Union as AnyOf def spam(x: AnyOf[int, float])->str: ... but not encouraged. (It's not that hard to learn a few standard names like Union.) So the above would work at runtime, but at compile time, it will depend on the specific linter or type checker: it will be a "quality of implementation" issue, with simple tools possibly not being able to recognise AnyOf as being the same as Union. Is this what you have in mind? -- Steven