Syntactic Sugar for Measurements in Swift

EasyMeasurements.swift

import Foundation

public typealias Mass = Measurement<UnitMass>
public typealias Duration = Measurement<UnitDuration>
public typealias Angle = Measurement<UnitAngle>
public typealias Length = Measurement<UnitLength>
public typealias Speed = Measurement<UnitSpeed>

public extension Measurement where UnitType: Dimension {
    static var zero: Measurement<UnitType> {
        Measurement(value: 0, unit: UnitType.baseUnit())
    }
}

public extension Double {
    func callAsFunction <U: Dimension>(_ units: U) -> Measurement<U> {
        Measurement(value: self, unit: units)
    }
}

public extension Int {
    func callAsFunction <U: Dimension>(_ units: U) -> Measurement<U> {
        Measurement(value: Double(self), unit: units)
    }
}

public extension UnitDuration {
    
    static let SecondsPerDay: Double = 86_400
    
    static let days   = UnitDuration("days", coefficient: SecondsPerDay)
    static let weeks  = UnitDuration("weeks", coefficient: SecondsPerDay * 7)
    static let months = UnitDuration("months", coefficient: SecondsPerDay * 30.417)
    static let years  = UnitDuration("years", coefficient: SecondsPerDay * 365)
    
    convenience init (_ symbol: String, coefficient: Double) {
        self.init(symbol: symbol, converter: UnitConverterLinear(coefficient: coefficient))
    }
}

public extension Measurement {
    init (_ value: Double, _ unit: UnitType) {
        self.init(value: value, unit: unit)
    }
}