Clean up interface to the PARI library, II

[pjbruin]

After #15185, the following changes are made in this ticket:

• The gen class currently contains duplicates of various methods of PariInstance (such as new_gen) for no obvious reason. These methods will be deleted.

• Remove obsolete code (e.g. add_unsafe, which currently is not used, and probably never should be).

Depends on #15185

CC: @jdemeyer

Component: interfaces

Keywords: pari

Author: Peter Bruin

Branch/Commit: u/pbruin/15461_clean_up_pari_interface @ 5bb8f8d

Reviewer: Jeroen Demeyer

Issue created by migration from https://trac.sagemath.org/ticket/15461

[pjbruin]

Branch: u/pbruin/15461_clean_up_pari_interface

[pjbruin]

Commit: 5bb8f8d

[pjbruin]

comment:4

This branch only deletes obsolete stuff and makes the minimal changes necessary to keep everything working. I think further (non-trivial) changes should probably wait until a different ticket.

---

Last 10 new commits:

[5bb8f8d](https://github.com/sagemath/sagetrac-mirror/commit/5bb8f8d)	remove commented-out method gen.python()
[3fa4f1d](https://github.com/sagemath/sagetrac-mirror/commit/3fa4f1d)	remove redundant methods from sage.libs.pari.gen
[511f05b](https://github.com/sagemath/sagetrac-mirror/commit/511f05b)	remove global variable mytop
[866f7fd](https://github.com/sagemath/sagetrac-mirror/commit/866f7fd)	remove methods sage.libs.pari.gen.*_unsafe
[05b93b7](https://github.com/sagemath/sagetrac-mirror/commit/05b93b7)	remove "pbw" as an abbreviation for "prec_bits_to_words"
[95a622a](https://github.com/sagemath/sagetrac-mirror/commit/95a622a)	better fix for real_double.pyx
[11a3bfb](https://github.com/sagemath/sagetrac-mirror/commit/11a3bfb)	more fixes related to relocation of PariInstance
[34013cc](https://github.com/sagemath/sagetrac-mirror/commit/34013cc)	fixes in sage.libs.pari
[db8cd7e](https://github.com/sagemath/sagetrac-mirror/commit/db8cd7e)	top-level changes related to PariInstance
[fcf7972](https://github.com/sagemath/sagetrac-mirror/commit/fcf7972)	adapt miscellaneous files in the Sage library

[jdemeyer]

Author: Peter Bruin

[jdemeyer]

Reviewer: Jeroen Demeyer

[jdemeyer]

comment:5

I think you should also remove the global variable prec from gen.pyx and replace prec by calls to prec_bits_to_words() (without argument).

[jdemeyer]

comment:6

Or that could go to a new ticket...

[jdemeyer]

comment:7

See #15523.