exactly
I'll try to get an updated PR in later tonight.
typelevel/squants#293
Essentially I'd like to take the algebraic representation of RPM or km/h or °C and record that
I could leave a 1.0 in there as the actual quantity if it helps I guess
Really I want to ser/des the units themselves so I can compare them later
So I can do an equality check when someone tries to do math on fields with known units
The compile-time type agreement is cool, but not what I'm after here :)
To get more concrete... In my metamodel, where the data dictionaries for customer streams and repositories are declared, I'd like to provide the ability to optionally annotate "this field is RPM, that field is degrees latitude, the other field is km/h"
The quantities themselves are numbers that come in at runtime as a result of queries or streams
And because the domain model is effectively infinite, I can't declare them statically as quantities-with-units
Eventually it'd be nice to have the units decomposable algebraically, so I could generate conversions
I'm trying to get something like this to work
val qty: Option[Quantity[_]] = X12CodeToUnitMap.get("IN").map{ uom: UnitOfMeasure[_] => uom.apply(6.0d) } but the typing continues to thwart me: (https://scastie.scala-lang.org/er1c/wSVcQmUYTM6LEdvw40jwLA)
@er1c Generally you should know ahead of time what dimension a given quantity is. This is important for any subsequent operations. For example, if you parse "3 mm", and wish to use that in additional dimensional analysis, you need to know that it is Length when you right that code. If you attempt to parse "4 kg" and then use it like a length you will get error. If you are not using these values in any analysis (i.e., perhaps you are just storing or displaying the values), then you may not need Squants for that. A simple Pair[Double, String] will work as no dimensional type-safety is required for that.
@garyKeorkunian I'm primarily looking to parse two different datasources that each have their own criteria, but convert between UOM. For instance, if I have a brake pad in a database with a thickness of .25 inches, I have a mapping table from the source "inches" to the
Inches LengthUnit as part of a Map, and I also know I need to convert it into mm for the European market based upon another mapping table that tells me "width" should be in mm instead of whatever the source UOM was :)
Hi everyone! What's the purpose of using Double as Information's underlying type? The Long should suit better, because, for example, there is no such N that N == N + 1 will evaluate to
true. For example Bytes(Double.MaxValue / 2.0) == (Bytes(Double.MaxValue / 2.0) + Bytes(1.0)) will evaluate to true. Things like 3.5 bytes also does make no sense.
it is
Double for historical reasons
The use of Double is a well-known issue. So far no one has wanted to put in the work to rework the library onto an abstract numetic type.
But had problems with the hierarchy of classes there
I’d simplify it in the process
In fact I can’t build squants on 2.13 due to the hirerachy
Refreshing memories... I want to record in my metadata catalog that the values in this random numeric field in a random data stream are °C
And that the values in this other field are RPM
And when a user asks me to add/subtract those, I want to check that the units are incompatible, and warn them not to... And if they're compatible (e.g. °C and °F) to insert the appropriate conversion in their function
