Make pynormaliz a Feature

[jplab]

As mentioned here: #25091 comment:69

We place the PythonModule feature for pynormaliz, already used in sage.geometry.polyhedron, in sage.features.normaliz.

This is preparation for #32174/#30746.

CC: @w-bruns @jplab @sebasguts @mkoeppe @videlec @kliem @kwankyu

Component: geometry

Keywords: polytopes, normaliz

Author: Matthias Koeppe

Branch/Commit: 7632e53

Reviewer: Kwankyu Lee

Issue created by migration from https://trac.sagemath.org/ticket/27744

[mkoeppe]

comment:1

You can just write

from sage.features import PythonModule
if PythonModule("PyNormaliz").is_present() ....

[jplab]

comment:2

Replying to @mkoeppe:

You can just write

from sage.features import PythonModule
if PythonModule("PyNormaliz").is_present() ....

Yes, that solves it for now. I thought, a long term goal is to do as was done for latte_int. Or I am mistaken?

[embray]

comment:3

As the Sage-8.8 release milestone is pending, we should delete the sage-8.8 milestone for tickets that are not actively being worked on or that still require significant work to move forward. If you feel that this ticket should be included in the next Sage release at the soonest please set its milestone to the next release milestone (sage-8.9).

[mkoeppe]

Dependencies: #30647

[mkoeppe]

Description changed:

--- 
+++ 
@@ -1,3 +1,3 @@
-As mentionned here: [#25091 comment:69](https://github.com/sagemath/sage/issues/25091#comment:69)
+As mentioned here: [#25091 comment:69](https://github.com/sagemath/sage/issues/25091#comment:69)
 
 The package pynormaliz should become a feature.

[mkoeppe]

comment:5

See #30647 for a new idiom - lazy_import with feature - that could replace code like this:

        PythonModule("PyNormaliz", spkg="pynormaliz").require()
        import PyNormaliz

throughout backend_normaliz.py.

[kliem]

comment:6

I do understand what is the goal of this ticket.

Do we want to make pynormaliz a standard package?

Or is this this new lazy import idiom better for python package that can also be installed via other sources (e.g. a pip install)?

[mkoeppe]

Branch: u/mkoeppe/make_pynormaliz_a_feature

[mkoeppe]

Description changed:

--- 
+++ 
@@ -1,3 +1,6 @@
 As mentioned here: [#25091 comment:69](https://github.com/sagemath/sage/issues/25091#comment:69)
 
-The package pynormaliz should become a feature.
+We place the `PythonModule` feature for pynormaliz, already used in `sage.geometry.polyhedron`, in `sage.features.normaliz`.
+
+This is preparation for #32174/#30746.
+

[mkoeppe]

New commits:

23f5009

sage.features.normaliz: New