Opened 4 years ago
Last modified 3 years ago
#26727 new defect
Make SR('x == 0') work, and likewise for <, >, <=, >=, !=, <>
Reported by: | slelievre | Owned by: | |
---|---|---|---|
Priority: | major | Milestone: | sage-wishlist |
Component: | symbolics | Keywords: | SymbolicRing, string, equation |
Cc: | slelievre | Merged in: | |
Authors: | Reviewers: | ||
Report Upstream: | N/A | Work issues: | |
Branch: | Commit: | ||
Dependencies: | Stopgaps: |
Description (last modified by )
While SR('3*x + 2')
correctly returns 3*x + 2
, calling SR
on
strings representing equations or inequations, such as
SR('x == 0')
or SR('x < 0')
or similar, choke on ==
, <
, etc.
All of the following are valid:
sage: x == 0 x == 0 sage: x < 0 x < 0 sage: x <= 0 x <= 0 sage: x > 0 x > 0 sage: x >= 0 x >= 0 sage: x != 0 x != 0 sage: x <> 0 x != 0
so one would expect the following to work too:
sage: SR('x == 0') x == 0 sage: SR('x < 0') x < 0 sage: SR('x <= 0') x <= 0 sage: SR('x > 0') x > 0 sage: SR('x >= 0') x >= 0 sage: SR('x != 0') x != 0 sage: SR('x <> 0') x != 0
Instead we get for example:
sage: print(version()) SageMath version 8.4, Release Date: 2018-10-17 sage: SR('x == 0') Traceback (most recent call last) ... TypeError: Malformed expression: x == !!! 0
Initially reported by Ludger O. Suarez-Burgoa in the discussion around Ask Sage question 41135.
Change History (3)
comment:1 Changed 4 years ago by
- Description modified (diff)
comment:2 Changed 4 years ago by
- Description modified (diff)
comment:3 Changed 3 years ago by
- Milestone changed from sage-8.5 to sage-wishlist
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