sage.categories: Remove module-level imports of sage.rings, sage.algebras, sage.matrix, sage.misc.latex, etc.

[mkoeppe]

This is for a cleaner, filtered structure of our Python modules, at least regarding their load time. This is preparation for #29865 (sage-objects).

The idea is that sage.categories should be more abstract than any of the implemented algebraic structures in sage.rings, sage.algebras, sage.modules, ... Therefore it should only have a (module load time) dependence on sage.structure and sage.misc.

The present ticket changes module-level imports to method-level imports so that they are resolved later than at module load time.

At run time, of course, there are additional dependencies. For example, as noted in #29705, the output of .cardinality() must be an integer (ZZ).

Also, obviously the doctests need a larger part of the library.

(split out from #29865)

Depends on #29869
Depends on #16351

CC: @videlec @tscrim @orlitzky @nthiery @timokau @fchapoton

Component: refactoring

Author: Matthias Koeppe

Branch/Commit: 27f2dab

Reviewer: Travis Scrimshaw

Issue created by migration from https://trac.sagemath.org/ticket/29873

[mkoeppe]

Dependencies: #29869

[mkoeppe]

Branch: u/mkoeppe/sage_categories_remove_module_level_imports

[mkoeppe]

New commits:

907feeb	Move attrcall and friends from sage.misc.misc to new module sage.misc.call
a5453bf	Fixup: Add src/sage/misc/call.py
64c5701	lazy_import from sage.misc.call with deprecation
65414f7	Fix imports and one deprecation warning
b9314d4	sage.misc.call: Add standard header information, add to reference manual
5e27414	sage.categories.crystals: Make import of sage.misc.latex local to a method
6e0fa7c	sage.categories: Make imports from sage.rings, .sets, .combinat, .plot, .matrix local to methods

[mkoeppe]

Commit: 6e0fa7c

[mkoeppe]

comment:6

Branch is on top of #29869.

[tscrim]

Reviewer: Travis Scrimshaw

[tscrim]

comment:7

In this code, these extra imports at the method level will not have a meaningful effect on the run time, so I am giving this a positive review based on that. However, this is something to be aware of as there can be functions in the category framework that are used in tighter loops.

[mkoeppe]

comment:8

Thanks! Yes, let's watch out for performance impacts of some of the upcoming changes.

[mkoeppe]

comment:9

Actually now I see

  File "/local/sage-patchbot/sage/local/lib/python3.7/site-packages/sage/combinat/backtrack.py", line 76, in <module>
    from sage.sets.recursively_enumerated_set import RecursivelyEnumeratedSet_generic
  File "sage/sets/recursively_enumerated_set.pyx", line 179, in init sage.sets.recursively_enumerated_set (build/cythonized/sage/sets/recursively_enumerated_set.c:12654)
ImportError: cannot import name SearchForest

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. This was a forced push. New commits:

6024ffd	src/sage/misc/call.py: register_unpickle_override for call_method
f3afd30	sage.categories.crystals: Make import of sage.misc.latex local to a method
6433a56	sage.categories: Make imports from sage.rings, .sets, .combinat, .plot, .matrix local to methods

[sagetrac-git]

Changed commit from 6e0fa7c to 6433a56

[mkoeppe]

comment:11

rebased on top of newer #29869

[mkoeppe]

comment:12

cyclic import, it seems

[mkoeppe]

comment:13

sage.combinat.backtrack notes a relevant todo:

    - For now the code of :class:`SearchForest` is still in
      ``sage/combinat/backtrack.py``.  It should be moved in
      ``sage/sets/recursively_enumerated_set.pyx`` into a class named
      :class:`RecursivelyEnumeratedSet_forest` in a later ticket.

[mkoeppe]

comment:14

that's apparently #16351.

[mkoeppe]

Changed dependencies from #29869 to #29869, #16351

[sagetrac-git]

Changed commit from 6433a56 to 5c20de7

[sagetrac-git]

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

364d7b3	Move SearchForest code to sage/sets/recursively_enumerated_set.pyx
68f7bd5	sage.combinat.integer_vectors_mod_permgroup: Update to use RecursivelyEnumeratedSet_forest
1764ca4	Update remaining uses of SearchForest to use RecursivelyEnumeratedSet_forest
1ac0a09	sage.combinat.backtrack: Remove deprecated class SearchForest
908acba	sage.combinat.backtrack: Remove deprecated classes TransitiveIdeal and TransitiveIdealGraded
5c20de7	Merge branch 't/16351/move_searchforest_code_to_sage_sets_recursively_enumerated_set_pyx' into t/29873/sage_categories_remove_module_level_imports

[mkoeppe]

comment:17

Merging #16351 fixed the ImportError.
Ready for review

[tscrim]

comment:19

One last little trivial thing, please add

# -*- coding: utf-8 -*-

as the first line to call.py. Once done, you can set a positive review.

[sagetrac-git]

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

27f2dab

src/sage/misc/call.py: Add coding directive

[sagetrac-git]

Changed commit from 5c20de7 to 27f2dab

[mkoeppe]

comment:21

Thanks!

[vbraun]

Changed branch from u/mkoeppe/sage_categories_remove_module_level_imports to 27f2dab