Backslash line continuation broken in Sage 9.2

[Eric Gourgoulhon]

In Sage 9.2, attempting to define a callable symbolic expression with a backslash line continuation yields a syntax error:

sage: f(x) = x \
....:        + 1                                                                                    

  File "<ipython-input-2-a5c1e14e19da>", line 1
    __tmp__=var("x"); f = symbolic_expression(x  * BackslashOperator() * ).function(x)
                                                                         ^
SyntaxError: invalid syntax

There was no such issue in Sage 9.1.

A culprit might be https://trac.sagemath.org/ticket/28974, since it deals with the preparser and backslashes, but I am not sure...

Eric.

[Eric Gourgoulhon]

Le lundi 16 novembre 2020 à 12:08:36 UTC+1, Eric Gourgoulhon a écrit :

A culprit might be https://trac.sagemath.org/ticket/28974, since it deals with the preparser and backslashes, but I am not sure...

Sorry it cannot be that one, since it has been merged only in Sage 9.3.beta0

[Eric Gourgoulhon]

I've opened https://trac.sagemath.org/ticket/30928 and set it to critical, since it is a failure of some basic Python syntax,

which may surprise many users.

PS: at the moment, I cannot do better dichotomy than saying that Sage 9.1 is free from the bug and 9.2.beta14 is not.