py3: fix FriCAS interface

[mantepse]

In python3, dict.items cannot be indexed. The processing of rootOf expression assumed this, so the design pattern must be changed.

Depends on #25899

CC: @fchapoton

Component: python3

Keywords: FriCAS

Author: Martin Rubey

Branch/Commit: 9a6ec3d

Reviewer: Travis Scrimshaw

Issue created by migration from https://trac.sagemath.org/ticket/27268

[mantepse]

Branch: u/mantepse/py3__fix_fricas_interface

[mantepse]

Author: Martin Rubey

[mantepse]

Commit: ec66106

[mantepse]

Description changed:

--- 
+++ 
@@ -1 +1 @@
-
+python3 likes modifying a dict one is iterating over even less than python2.

[mantepse]

Dependencies: #25899

[mantepse]

New commits:

ec66106

fix treatment of rootOf expressions for python3

[slel]

comment:3

Might this help with #17908 and #25905? Should there also be a register_symbol for abs?

[mantepse]

comment:4

• 25905 has a bad description - the bug is further down the comments, and is a true fricas bug

• I didn't know about #17908, thank you for notifying me! Yes, the cure is very likely now simply adding the translation of abs, I'll keep this in mind.

• this ticket is unrelated to the two above, it only provides a python3 fix. However, to avoid merge conflicts, I'd like to get in this ticket and #26068 first, I'll then do #17908.

[slel]

comment:5

Replying to @mantepse:

... thank you for notifying me! ...

You can query Trac for all tickets whose summary contains "fricas":

• https://trac.sagemath.org/query?order=id&desc=1&summary=~fricas.

[mantepse]

Changed keywords from none to FriCAS

[7ed8c4ca-6d56-4ae9-953a-41e42b4ed313]

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

9a6ec3d

Merge branch 'develop' of git://trac.sagemath.org/sage into t/27268/py3__fix_fricas_interface

[7ed8c4ca-6d56-4ae9-953a-41e42b4ed313]

Changed commit from ec66106 to 9a6ec3d

[tscrim]

Reviewer: Travis Scrimshaw

[tscrim]

comment:8

Actually, the problem is this line: (var, poly) = rootOf.items()[i]. The result of items() is a view, which does not support indexing (in a way, think of it like an iterator). However, since your changes work and the code looks cleaner, positive review.

[mantepse]

comment:9

Replying to @tscrim:

Actually, the problem is this line: (var, poly) = rootOf.items()[i].

Yes, the error message and trace did show that.

The result of items() is a view, which does not support indexing (in a way, think of it like an iterator). However, since your changes work and the code looks cleaner, positive review.

General question: should I modify the ticket description once I know the root of the problem? The downside is that the history how the bugfix developed is sometimes not as easy to understand anymore.

[tscrim]

comment:10

Yes, in this case it probably is better to modify it so that people have an easier time seeing the issue (rather than reading the comments).

[mantepse]

Description changed:

--- 
+++ 
@@ -1 +1 @@
-python3 likes modifying a dict one is iterating over even less than python2.
+In python3, `dict.items` cannot be indexed.  The processing of `rootOf` expression assumed this, so the design pattern must be changed.

[vbraun]

Changed branch from u/mantepse/py3__fix_fricas_interface to 9a6ec3d