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.up

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