sage_input for SR

[mkoeppe]

sage: var('x')
x
sage: sage_input(x)
ValueError: Can't convert x to sage_input form

CC: @vbraun @rwst

Component: symbolics

Branch/Commit: u/mkoeppe/sage_input_for_sr @ d8eee32

Issue created by migration from https://trac.sagemath.org/ticket/22393

[mkoeppe]

Branch: u/mkoeppe/sage_input_for_sr

[sagetrac-tmonteil]

comment:2

I fear this is not enough for wilder symbolic expressions:

sage: a = SR(Zmod(4)(5))
sage: a
1
sage: a.parent()
Symbolic Ring
sage: a*6
2
sage: SR(repr(a)) * 6
6

[sagetrac-tmonteil]

Commit: d8eee32