#17186: Inverted F expression (negation)
-------------------------------------+-------------------------------------
Reporter: niwi | Owner: nobody
Type: New feature | Status: new
Component: Database layer | Version: SVN
(models, ORM) | Resolution:
Severity: Normal | Triage Stage: Accepted
Keywords: | Needs documentation: 0
Has patch: 1 | Patch needs improvement: 0
Needs tests: 0 | UI/UX: 0
Easy pickings: 0 |
-------------------------------------+-------------------------------------
Comment (by nate_b):
There are several problems with this patch.
For example, you should be able to negate compound expressions:
{{{#!python
>>> Demo.objects.filter(a_field=~(F('a_field')+1))
Traceback (most recent call last):
File "<console>", line 1, in <module>
TypeError: bad operand type for unary ~: 'ExpressionNode'
}}}
Secondly, there is no indication of negation in the string representation,
like there is for other operators:
{{{#!python
>>> print ~F('field')
(DEFAULT: )
>>> print F('field') + F('other')
(+: (DEFAULT: ), (DEFAULT: ))
}}}
Thirdly, {{{tree.Node}}} already supplies a {{{negate()}}} function and a
{{{negated}}} field. Why not use those instead?
I'm not entirely pleased with my alternative as it still doesn't make use
of {{{connector}}}, but it solves these listed problems.
--
Ticket URL: <https://code.djangoproject.com/ticket/17186#comment:4>
Django <https://code.djangoproject.com/>
The Web framework for perfectionists with deadlines.
--
You received this message because you are subscribed to the Google Groups
"Django updates" group.
To post to this group, send email to django-updates@googlegroups.com.
To unsubscribe from this group, send email to
django-updates+unsubscr...@googlegroups.com.
For more options, visit this group at
http://groups.google.com/group/django-updates?hl=en.
