MaximaElements should not coerce into SR.

[mwhansen]

sage: f = maxima.function('x','sin(x)')
sage: f + x  #correct
sin(x)+x
sage: x+f    #wrong
x + sage6

Component: calculus

Author: Mike Hansen

Reviewer: Adam Webb

Merged: sage-4.2.alpha0

Issue created by migration from https://trac.sagemath.org/ticket/3970

[mwhansen]

comment:1

After:

sage: f = maxima.function('x','sin(x)')
sage: f+x
sin(x)+x
sage: x+f
sin(x)+x
sage: type(_)
<class 'sage.interfaces.maxima.MaximaFunction'>

[mwhansen]

Description changed:

--- 
+++ 
@@ -1 +1,8 @@
 
+```
+sage: f = maxima.function('x','sin(x)')
+sage: f + x  #correct
+sin(x)+x
+sage: x+f    #wrong
+x + sage6
+```

[mwhansen]

comment:2

Patch added which fixes the issue. This depends on #132.

[mwhansen]

comment:3

This patch actually breaks everything in calculus.py. I must have ran the tests without having it actually applied.

[jasongrout]

comment:4

What is the status of this now? Apparently it still is a problem in 4.0:

----------------------------------------------------------------------
| Sage Version 4.0, Release Date: 2009-05-29                         |
| Type notebook() for the GUI, and license() for information.        |
----------------------------------------------------------------------
sage: f = maxima.function('x','sin(x)')
sage: f + x  #correct
sin(x)+x
sage: x+f    #wrong
sage0 + x
sage: 

[mwhansen]

Author: Mike Hansen