Serialization

[hwiesmann]

What is the recommended way to do quantity serialization?

I have to admit that I am currently not deeply familiar with the library as I am currently evaluating which "units" library to use. One requirement is to easily being able to serialize the quantity using cereal, protobuf or others.

Best regards,
Hardy

[mpusz]

Hi @hwiesmann, Thank you for your interest in the library. Serializing the underlying quantity value should not be a problem. Just call quantity.numerical_value_in(Unit) on a given quantity. Deserialization may be a bit more complicated as a quantity can't be created from just a value. It always needs a unit as well. You can either use a multiply syntax or a 2-parameter constructor.

If you want to serialize a unit or a quantity type, please note that the majority of such libraries on the market require this information to be known at compile-time. This means that you can't dynamically create any quantity with any unit from the stream. So, there is probably no sense in serializing a unit and a quantity type at all. If this was your use case, then you might be interested in #483. Please share your use case there so we will have more motivation for this feature if we try to implement it and then possibly "sell" to the ISO C++ Committee.

[hwiesmann]

Hi

in my serialization use case I would not need a dynamic creation (with respect to units) for quantities. I like to serialize something like this:

`class Demo
{
quantitysi::metre,double m_Length;
};

...
Demo demo;

serialize(demo);

deserialize(demo);
`
So, the type is explicitly known. I have more issues on how to serialize the unit itself than the value of the quantity.

[mpusz]

I am afraid that I do not follow. A unit is a part of a type. If you know the type you also know a unit. In such a case the only thing you need to serialize is the numerical value of the quantity.

[hwiesmann]

Hi, Sorry, I was a bit confused. Just forget my last message.

…

Am 27.12.2024 um 13:09 schrieb Mateusz Pusz ***@***.***>: I am afraid that I do not follow. A unit is a part of a type. If you know the type you also know a unit. In such a case the only thing you need to serialize is the numerical value of the quantity. — Reply to this email directly, view it on GitHub <#661 (reply in thread)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAD6V3GAONNWK332REBWX632HU7QXAVCNFSM6AAAAABUF5RTU6VHI2DSMVQWIX3LMV43URDJONRXK43TNFXW4Q3PNVWWK3TUHMYTCNRXG4YTCNQ>. You are receiving this because you were mentioned.