On terça-feira, 21 de agosto de 2012 10.21.12, Harald Fernengel wrote: > Note that the concept of "NULL" values, while generally a bad idea, is a > concept required for the SQL module. SQL has the conecpt of "NULL" as an > extra flag for every value (date, int, string, etc. etc.). > > That's why we added the is_null bitfield as extra flag on every QVariant, > and allowed people to construct QVariants that had a valid type but not a > non- valid (NULL) value.
A-ha! That explains where it came from! I had a work-in-progress patch to add a QMaybe<T> type which would allow you to keep the nullability even outside QVariant. The name comes from Haskell. See http://en.wikipedia.org/wiki/Maybe_type. -- Thiago Macieira - thiago.macieira (AT) intel.com Software Architect - Intel Open Source Technology Center Intel Sweden AB - Registration Number: 556189-6027 Knarrarnäsgatan 15, 164 40 Kista, Stockholm, Sweden
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