Opened 5 years ago

Closed 5 years ago

#23419 closed enhancement (fixed)

New function can_assign_class() to partially replace is_extension_type()

Reported by: jdemeyer Owned by:
Priority: major Milestone: sage-8.1
Component: cython Keywords:
Cc: nthiery, dkrenn Merged in:
Authors: Jeroen Demeyer Reviewers: Travis Scrimshaw
Report Upstream: N/A Work issues:
Branch: d6ab4da (Commits, GitHub, GitLab) Commit: d6ab4daa85d73700d7a6d0f5eb23d302c671675d
Dependencies: Stopgaps:

Status badges

Description (last modified by jdemeyer)

The semantics of both Python types and Cython types have changed a lot since is_extension_type() was first written. In order to make it more clear why is_extension_type() is used, I suggest to replace it by more specific functions.

In this ticket, I implement a new function can_assign_class(obj) to determine whether obj.__class__ can be assigned to.

This also changes underlying_class from a function to a method of CategoryObject.

Change History (10)

comment:1 Changed 5 years ago by jdemeyer

  • Cc dkrenn added
  • Description modified (diff)

comment:2 Changed 5 years ago by jdemeyer

  • Branch set to u/jdemeyer/new_function_can_assign_class___to_partially_replace_is_extension_type__

comment:3 Changed 5 years ago by jdemeyer

  • Commit set to 6cb44f89a4478d711ba829d2cea0f8548623f989
  • Status changed from new to needs_review

New commits:

​cf224b7Implement wrapperdescr_call without checking
​9a4ef8cWording
​ed0d88cMove various things to src/sage/cpython
​6cb44f8New function can_assign_class()

comment:4 Changed 5 years ago by jdemeyer

  • Description modified (diff)

comment:5 Changed 5 years ago by jdemeyer

  • Dependencies #23413 deleted

comment:6 follow-up: Changed 5 years ago by tscrim

I think we should hide _underlying_class from the public interface (well, specifically tab-completion).

Also, why the change in the test order? 

-            if not issubclass(self.__class__, Sets_parent_class) and not is_extension_type(self.__class__):
+            if can_assign_class(self) and not issubclass(self.__class__, Sets_parent_class):

(I don't object, but I am curious if there is a reason.)

comment:7 in reply to: ↑ 6 Changed 5 years ago by jdemeyer

Replying to tscrim:

Also, why the change in the test order?

Efficiency. Checking can_assign_class is very fast, so it's good to do that first.

comment:8 Changed 5 years ago by git

  • Commit changed from 6cb44f89a4478d711ba829d2cea0f8548623f989 to d6ab4daa85d73700d7a6d0f5eb23d302c671675d

Branch pushed to git repo; I updated commit sha1. New commits:

​d6ab4daMake _underlying_class private

comment:9 Changed 5 years ago by tscrim

  • Reviewers set to Travis Scrimshaw
  • Status changed from needs_review to positive_review

Thanks.

comment:10 Changed 5 years ago by vbraun

  • Branch changed from u/jdemeyer/new_function_can_assign_class___to_partially_replace_is_extension_type__ to d6ab4daa85d73700d7a6d0f5eb23d302c671675d
  • Resolution set to fixed
  • Status changed from positive_review to closed
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