Hi list,
Hope everyone's having a splendid day/evening/whatever.
I've encountered a strange error. I have two chunks
of nearly identical code below. The only difference
is the first if statement. One has:
if context:
the other has:
if context is not None
The first fails to be true even if context is not None.
This can be seen by the output from the logs showing the
context variable as:
777 Context
books.finance.fiscalyear.FiscalYearSQLContainer object at 0xad90aac
TitledAbsoluteURL.breadcrumbs, calling getBreadCrumbTitle
getBreadCrumbTitle, no context.
When I changed it to the second form (i.e. not None) the
context is OK and the code works. Why does the object
'context' not evaluate to true? This is a nasty gotcha that
I'd like to understand.
I thought that any object that exists (and doesn't equal
zero, '' or False) resolves to true. Can anyone help?
I'm still pretty new to python and zope so be gentle.
I've made sure that the proper parameters are being passed
to the function and so on.
Thanks in advance!
Mark
P.S. I hope there wasn't any horrible wrapping...
didn't work =
= source ==
def getBreadCrumbTitle(context=None, default=None):
Helper function to get a title for an URL breadcrumb list.
title = None
if context:
print , removeSecurityProxy(context)
title = getattr(context, 'title', None)
if title is None:
print Title not an attribute of context, setting to
default.
title = default
try:
annotations = IZopeDublinCore(context)
if annotations:
print Annotations, annotations
try:
title = annotations.title
print Annotation's Title, annotations.title
except KeyError:
print Annotation's Title KeyError
pass
else:
print Annotations adapted but empty.
except TypeError:
print Annotations not available-No Adaption to Dublin
Core
pass
else:
print getBreadCrumbTitle, Title not None-gotten from
getattr
else:
print getBreadCrumbTitle, no context.
if title is None:
raise TypeError(_insufficientTitleContext)
else:
print getBreadCrumbTitle, Title is not None, title
return title
== log ===
{'__name__': u'FY', '_class': class
'books.finance.fiscalyear.FiscalYear', '_className':
u'books.finance.fiscalyear.FiscalYear', '__parent__':
zope.app.folder.folder.Folder object at 0xad747ac}
TitledSiteAbsoluteURL.breadcrumbs, calling getBreadCrumbTitle
zope.app.folder.folder.Folder object at 0xad747ac
Title not an attribute of context, setting to default.
Annotations zope.dublincore.annotatableadapter.ZDCAnnotatableAdapter
object at 0xadd8cac
Annotation's Title huh
getBreadCrumbTitle, Title is not None huh
777 Context
books.finance.fiscalyear.FiscalYearSQLContainer object at 0xad90aac
TitledAbsoluteURL.breadcrumbs, calling getBreadCrumbTitle
getBreadCrumbTitle, no context.
==
worked =
source =
def getBreadCrumbTitle(context=None, default=None):
Helper function to get a title for an URL breadcrumb list.
title = None
if context is not None:
print , removeSecurityProxy(context)
title = getattr(context, 'title', None)
if title is None:
print Title not an attribute of context, setting to
default.
title = default
try:
annotations = IZopeDublinCore(context)
if annotations:
print Annotations, annotations
try:
title = annotations.title
print Annotation's Title, annotations.title
except KeyError:
print Annotation's Title KeyError
pass
else:
print Annotations adapted but empty.
except TypeError:
print Annotations not available-No Adaption to Dublin
Core
pass
else:
print getBreadCrumbTitle, Title not None-gotten from
getattr
else:
print 4, removeSecurityProxy(context)
print getBreadCrumbTitle, no context.
if title is None:
raise TypeError(_insufficientTitleContext)
else:
print getBreadCrumbTitle, Title is not None, title
return title
== log
{'__name__': u'FY', '_class': class
'books.finance.fiscalyear.FiscalYear', '_className':
