deprecate some cmp keyword in favor of key in factorizations

[fchapoton]

as a step towards python3

let us try to get rid of cmp= in factorizations

CC: @tscrim @jm58660 @jdemeyer

Component: python3

Author: Frédéric Chapoton

Branch/Commit: 930414a

Reviewer: Travis Scrimshaw

Issue created by migration from https://trac.sagemath.org/ticket/21145

[fchapoton]

Branch: public/21145

[fchapoton]

Author: Frédéric Chapoton

[fchapoton]

New commits:

6406454

trac 21145 first tentative

[fchapoton]

Commit: 6406454

[sagetrac-git]

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

3b72723

trac 21145 more work on deprecating cmp in factorisations

[sagetrac-git]

Changed commit from 6406454 to 3b72723

[sagetrac-git]

Changed commit from 3b72723 to d23c60a

[sagetrac-git]

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

d23c60a

no change to ordered tree (moved to another ticket)

[sagetrac-git]

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

24f0320

trac 21145 work on cmp in factorisations

[sagetrac-git]

Changed commit from d23c60a to 24f0320

[sagetrac-git]

Changed commit from 24f0320 to d2531cf

[sagetrac-git]

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

d2531cf

trac #21145 fixing one failing doctest

[fchapoton]

comment:7

bot is green !

[a-andre]

comment:8

Calls like self.__x.sort(cmp=_cmp) will crash in python 3. I suggest you use cmp_to_key() from functools:
self.__x.sort(key=cmp_to_key(_cmp))

[tscrim]

comment:9

LGTM.

@a-andre Those should go away by the time we switch to Python3 (hopefully we will be there before EOL for Python2).

[tscrim]

Reviewer: Travis Scrimshaw

[tscrim]

comment:10

Actually, I now understand Andre's comment, we should change

-self.__x.sort(cmp=_cmp)
+self.__x.sort(key=cmp_to_key(_cmp))

in the deprecated code to be python2/3 compatible now (I interpreted it as a long-term, sorry!).

[sagetrac-git]

Changed commit from d2531cf to 930414a

[sagetrac-git]

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

930414a

trac #21145 using cmp_to_key in deprecated code

[tscrim]

comment:13

Thanks, and sorry I didn't understand it earlier.

[vbraun]

Changed branch from public/21145 to 930414a