Provide angular units

[teajay-fr]

Currently no angular units are provided.
This would be necessary to be able to handle all rotational phenomenon such as a rotating wheel or motor :)

The required base units would be:

• degrees
• radians
• grad
  Angular velocity and acceleration would also make sense.

[mpusz]

Actually, it is not true.

In the following directory https://github.com/mpusz/units/tree/master/src/include/units/generic you will find both an experimental angular dimension and a dimensionless quantity. Here https://github.com/mpusz/units/blob/master/src/include/units/physical/si/derived/angular_velocity.h you can find the implementation of the angular_velocity that uses this experimental angle unit. We also have torque: https://github.com/mpusz/units/blob/master/src/include/units/physical/si/derived/torque.h.

It is still unclear if we should stay with an angular dimension or use dimensionless quantity for those. You can find the discussion in #99. We need more experience and this is why we have both options for now here.

Regarding degrees vs radians we have another big issue here as pi would need to be encoded as a compile-time ratio which will result in ratio overflows easily. See more in #169.

[teajay-fr]

Thank you for pointing this out, I missed the discussion and units already present in my research. I'll close this issue and add some input to the other discussions.

[mpusz]

Implemented with:

• 8b534c8
• 7719776
• a92a315