Defaults in form - note that only fields with form.skip get default when submitted with no value (empty input that becomes null, as in [DefOptMayBeNullEmptyIsNull])

Printer: print

Def *	World
Def Empty Is Null *this cannot be submitted empty, raises error and shows again with default filled	World
Def Opt	World
Def Opt May Be Null	World
Def Opt May Be Null Empty Is Nullhere the default is not set if the input is empty so value is null	World
Def Opt Empty Is Nullhere an empty value causes the input to be removed on submission, no value in result	World