AnyMeasure
Swift For Any Measure: Simplified
A clean, Swift interface for Foundation.Measurement
Read my post about it here.
Requirements: Swift 4.0+
Motivation
The idea of type-safe numeric values, in other words, Measurements
sounds great but, alas, the ergonomics are poor. At least until
now. Wouldn’t it be great to do this
let m: Mass = 123(.kilograms) + 17(.stones)
// or let m = Mass(123, .kilograms) + 17(.stones)
m.converted(to: .pounds) // 509.1688786398349 lb
instead of this?
let m = Measurement(value: 123, unit: UnitMass.kilograms)
let m2 = m + Measurement(value: 17, unit: UnitMass.stones)
print (m2.converted(to: .pounds)) // 509.1688786398349 lb
In addition to its verboseness, the Foundation Unit and Measurement
APIs also lack the ability to dynamically declare compound units.
This can make it difficult to perform dimensional analysis
and other multi-step calculations.
The Ratio
structure allows you to express the ratio
between two units in a type-safe manner
Multiplying a measurement with one unit type by a rate
whose denominator is that same unit type causes those types to cancel out,
resulting in a measurement with the numerator type.
Usage
For example, volume over time multiplied by time yields volume:
// Ratio of Measures
typealias FlowRate = Ratio<UnitVolume, UnitDuration>
let rate: FlowRate = 84760(.cubicFeet, per: .seconds)
let dailyFlow = (rate * 24(.hours)).converted(to: .megaliters)
// -> ~ 207371ML
Installation
Swift Package Manager
Add the Rate package to your target dependencies in Package.swift
:
import PackageDescription
let package = Package(
name: "YourProject",
dependencies: [
.package(
url: "https://github.com/wildthink/anymeasure",
from: "1.0.0"
),
]
)
Then run the swift build
command to build your project.
Contact
- Medium: Measurements in Swift
- @JasonJobe17
License Information
MIT – See LICENSE.md
Credits
Thanks to
- Flight School: Read Evaluate Press for Rate.swift
Original Code at https://github.com/Flight-School/Rate
This functionality is discussed in Chapter 5 of
Flight School Guide to Swift Numbers.