#15990: Python 3 preparation: Change syntax of raise statement
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Reporter: wluebbe | Owner:
Type: enhancement | Status: new
Priority: major | Milestone: sage-6.2
Component: distribution | Keywords: python3
Merged in: | Authors:
Reviewers: | Report Upstream: N/A
Work issues: | Branch:
Commit: | Dependencies:
Stopgaps: |
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Only the modern syntax like {{{raise E(V)}}} and {{{raise
E(V).with_traceback(T)}}} is accepted by Python 3.[[br]]
Almost all cases change {{{raise E, V}}} to {{{raise E(V)}}} where V is a
string.
**TODO**:
* Clarify why the cases {{{with_traceback}}} were omitted in
{{{libfuturize/fixes/raise.py}}}. (Perhaps this belongs to //stage 2//?)
Changes according to {{{lib2to3/fixes/fix_raise.py}}}:
{{{
raise -> raise
raise E -> raise E
raise E, V -> raise E(V)
raise E, V, T -> raise E(V).with_traceback(T)
raise E, None, T -> raise E.with_traceback(T)
raise (((E, E'), E''), E'''), V -> raise E(V)
raise "foo", V, T -> warns about string exceptions
CAVEATS:
"raise E, V" will be incorrectly translated if V is an exception
instance. The correct Python 3 idiom is
raise E from V
but since we can't detect instance-hood by syntax alone and since
any client code would have to be changed as well, we don't automate
this.
}}}
--
Ticket URL: <http://trac.sagemath.org/ticket/15990>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
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