Martin Aspeli wrote:
Hi,
Sorry for doing this by email rather than unit test, but I'm a bit
over-stretched at the moment.
plone.z3cform has a backport of z3c.form trunk's TextLines widget
(when's that release coming, any ideas?).
In using it, I discovered that the converter (converter.py on z3c.form
trunk) does this:
def toFieldValue(self, value):
See interfaces.IDataConverter
widget = self.widget
collectionType = self.field._type
if isinstance(collectionType, tuple):
collectionType = collectionType[-1]
if not len(value):
return self.field.missing_value
valueType = self.field.value_type._type
if isinstance(valueType, tuple):
valueType = valueType[0]
return collectionType(valueType(v) for v in value.split())
I was just wondering: should we not try to use IFromUnicode when
converting the value type? This would be safer, and probably allow us to
support more value_types. Arguably, we should *require* that the
value_type for this widget provides IFromUnicode, but we could have the
fallback _type cast like this.
A simple implementation would be:
def toFieldValue(self, value):
See interfaces.IDataConverter
widget = self.widget
collectionType = self.field._type
if isinstance(collectionType, tuple):
collectionType = collectionType[-1]
if not len(value):
return self.field.missing_value
value_type = self.field.value_type
cast = None
fromUnicode = IFromUnicode(value_type, None)
if fromUnicode is not None:
cast = fromUnicode.fromUnicode
else:
cast = value_type._type
if isinstance(cast, (tuple,list)):
cast = cast[0]
return collectionType(cast(v) for v in value.split())
And another thing... Would it make sense to always return a sorted list
for sets? Something like:
class TextLinesSetConverter(TextLinesConverter):
zope.component.adapts(
zope.schema.interfaces.ISet, ITextLinesWidget)
def toWidgetValue(self, value):
if value is self.field.missing_value:
return u''
return u'\n'.join(unicode(v) for v in sorted(value))
class TextLinesFrozenSetConverter(TextLinesConverter):
zope.component.adapts(
zope.schema.interfaces.IFrozenSet, ITextLinesWidget)
def toWidgetValue(self, value):
if value is self.field.missing_value:
return u''
return u'\n'.join(unicode(v) for v in sorted(value))
It's confusing to users when the widget renders the value in seemingly
random order. :)
Martin
--
Author of `Professional Plone Development`, a book for developers who
want to work with Plone. See http://martinaspeli.net/plone-book
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