Q: Is it possible to create values ​​from string types?

[khasrusn]

Thank you for the project.

I have a need to write a function to convert different units of measurement of the following type:

double convert(double value, std::string from_unit, std::string to_unit)
{
    double converted_val = ...;
    return converted_val;
}

int main()
{
    std::cout << "100 cm = " << convert(100.0, "cm", "m") << " meters" << std::endl;
    std::cout << "1 day = " << convert(1.0, "day", "hour") << " hours" << std::endl;
    ...
}

When trying to write such a converter I encounter problems with strong typing of quantities and I lack the experience to get around them. I understand that I can write a function to convert using if-else if blocks, but what if my project requires converting a large number of different units of measurement? Please tell me if it is possible to solve my problem using your library or should I look for other libraries?

[mpusz]

Hi @khasrusn! The majority of C++ units libraries are about compile-time type safety. This requires strong types, as you stated. This, however, also means that you can't dynamically create a quantity at runtime without knowing its type upfront.

Said that we have two issues that might help you when/if they are resolved:

• Text input support #541 will provide text input (but for compile-time known types,
• polymorphic_unit??? #483 may provide polymorphic support for various units of a specific quantity type/dimension.