On Wed, Mar 18, 2009 at 07:31:36AM -0400, Tres Seaver wrote:
Roger Ineichen wrote:
Hi Malthe
Betreff: [Zope-dev] ZPT attributes and ""
Currently, if an attribute expression evaluates to any value that's boolean False, it's omitted (e.g. 0, "", object()).
object() is true in boolean contexts.
I think that's unexpected. Instead, attributes should only be omitted when the expression evaluates to ``None``.
I think this is better then render empty strings. see below...
How do folks feel about changing this behavior in ``zope.pagetemplate``.
Probably anything else then "" should be skipped. There is no logic why object() or False should get rendered as "".
Non-true values have special semantics for certain attributes ('checked', 'selected', I think).
True values also. This is a feature of TAL in HTML mode and should be preserved <input type="checkbox" tal:attributes="checked some_bool_expr" /> Marius Gedminas -- http://pov.lt/ -- Zope 3 consulting and development