Doctest sage.categories.action

[roed314]

Currently there are no doctests in this file.

---

Apply attachment: 12039_doctests.patch, attachment: 12039_outside.patch, attachment: 12039_example.patch, attachment: 12039_changes_v2.patch

Depends on #12048

Component: doctest coverage

Keywords: sd40.5

Author: David Roe

Reviewer: Florent Hivert, David Loeffler, Karl-Dieter Crisman

Issue created by migration from https://trac.sagemath.org/ticket/12039

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Attachment: 12039_doctests.patch.gz

Doctests and changes sage.categories.action

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Some changes outside sage.categories.action and sage.categories.action_example

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Dependencies: #12048

[roed314]

comment:1

Attachment: 12039_outside.patch.gz

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Author: David Roe

[hivert]

comment:2

I was googling for LazyFormat when I stumbled here.

One remark: There is no need to use LazyFormat if the result is a plain string. Just use the string itself. The purpose of LazyFormat is the following: when you have

lz=LazyFormat("... %s ...")%(obj)

it defers the computation of __repr__(obj) until one call __repr__(lz). So that,

LazyFormat("Message")%(())

is really some kind of overkill.

[hivert]

Reviewer: Florent Hivert

[hivert]

comment:3

A followup for my last remark. The idea of LazyFormat is to be able to
print counter examples in the error message for TestSuite when a property is
wrong, without drastically slowing down the tests. I would therefore suggest
to replace

tester.assertTrue(self(a, self(b, v)) == self(a*b, v), 
                  LazyFormat("Multiplication is not associative")%(())) 

by

tester.assertTrue(self(a, self(b, v)) == self(a*b, v), 
    LazyFormat("Multiplication is not associative: %s*(%s*%s) != (%s*%s)*%s")%(a,b,v,a,b,v))

And similarly for the other one.

Also in the category directory, the usage is to place the example in the
subdirectory examples. An action isn't really a category, but I think it would
be good to have all the examples there. Moreover, don't forget to add your
very nice example in the reference manual (file: doc/en/reference/categories.rst).

By the way: thanks a lot for writing all this nice documentation.

Florent

[hivert]

comment:4

More remarks:

• There is an empty Example:: section for _extend_G(self, K):.

• you should put hyperlinks ref for :class:`sage.matrix.action.MatrixMatrixAction` line 14 in sage/categories/action.pyx, as well as in

17	See sage.structure.coerce_actions and sage.matrix.action for examples of Actions  
18	used in the coercion system, and sage.structure.coerce and sage.structure.parent 
19	for the code that uses them. 

Note: I didn't look exhaustively for missing hyperlinks.

Sorry for asking all these modifications. More review tomorrow morning, I'm off to bed.

Florent