Feature request (or help request)

[Lucretiel]

Is it possible to instantiate a Quantity with a known type but a runtime unit of measure? For instance, suppose I have the float value 2.5 and the string "km". Is there any way to parse that aside from formatting the quantity back into a string and using FromStr? If not, this is a feature request from a constructor or an enum of different unit measures of a each type that can be parsed and used to construct quantities.

[iliekturtles]

There isn't a way to do this right now and two issues prevent it: there isn't a way to just parse "km" into the appropriate unit and there is no new constructor that can take a unit at runtime. I just added #220 to resolve the former and #91 is open to resolve the later. The recent merge of #215, which added the Unit enum, should make both of these possible.

Let me know if the resolution of those two issues will resolve your problem so we can mark this issue complete.

[Lucretiel]

Yup, those will definitely cover it!

[Lucretiel]

I suppose a stopgap solution would be to parse "1 {unit}" and multiply by the untyped quantity

[iliekturtles]

Marking this issue closed since the other two cover the functionality needed. Please re-open if I missed anything!

[Lucretiel]

For those finding there way here looking for a way to do this before the features land, I've found that format!("1.0 {unit}", unit=unit_str).parse() works perfectly.