[Qt-interest] QVariant is great, make it better

[Mildred Ki'Lya]

Hi,

I use lots and lots of QVariant, and I'll have to use user defined
QVariant types.

Now, I would like to suggest a new feature that could be added at some
point in the future: integrate user QVariants with the others.

Say for example I create a value representing an IPv4 address, The class
could be like:

class IPv4 {
    unsigned char a, b, c, d;
    ...
};
Q_DECLARE_METATYPE(IPv4)


It would be great if when I had an IPv4 QVariant, I could just write
variant.toString() and have the pointed notation for the IP address.
Like 127.0.0.1

It would also be great that given a string QVariant, the
variant.value<IPv4>() would convert the string to an IP address.

I think it would be really great.

The way I think it could be done would be using meta methods. For
example there would be a method that would return a QVariant of a
desired type. And a method that would convert a QVariant into the
targetted type.

For example I would have:

QVariant IPv4::qvariantToType(QVariant::Type t); // convert this to a
QVariant of type t
QVariant IPv4::qvariantFromValue(QVariant origin); // convert origin to
an IPv4 QVariant

Well, that could be done outside the QVariant class, but it would be
really great I think if there was some functionnality like this.


Mildred

-- 
Mildred Ki'Lya
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