Global functions for providing device specific values in Swift.

ValueForDevice.swift

import Foundation

/*
Put these global functions in a file that is compiled for all platforms.
*/

/// Returns the value for the current device from the values that are provided.
///
/// - Parameters:
///   - phoneValue: The value to use for iPhone.
///   - padValue: The value to use for iPad.
///   - macValue: The value to use for Mac.
///   - defaultValue: The default value to use for all other devices.
func valueForDevice<Value>(phone phoneValue: @autoclosure () -> Value, pad padValue: @autoclosure () -> Value, mac macValue: @autoclosure () -> Value, defaultValue: @autoclosure () -> Value) -> Value {
    _valueForDevice(phone: phoneValue, pad: padValue, mac: macValue, defaultValue: defaultValue)
}

/// Returns the value for the current device from the values that are provided.
///
/// - Parameters:
///   - phoneValue: The value to use for iPhone.
///   - padValue: The value to use for iPad.
///   - macValue: The value to use for Mac.
///   - defaultValue: The default value to use for all other devices.
func valueForDevice<Value: Numeric>(phone phoneValue: @autoclosure () -> Value, pad padValue: @autoclosure () -> Value, mac macValue: @autoclosure () -> Value, defaultValue: @autoclosure () -> Value = .zero) -> Value {
    _valueForDevice(phone: phoneValue, pad: padValue, mac: macValue, defaultValue: defaultValue)
}

/// Returns the value for the current device from the values that are provided.
///
/// - Parameters:
///   - phoneValue: The value to use for iPhone.
///   - padValue: The value to use for iPad.
///   - macValue: The value to use for Mac.
///   - defaultValue: The default value to use for all other devices.
func valueForDevice<Wrapped>(phone phoneValue: @autoclosure () -> Optional<Wrapped>, pad padValue: @autoclosure () -> Optional<Wrapped>, mac macValue: @autoclosure () -> Optional<Wrapped>, defaultValue: @autoclosure () -> Optional<Wrapped> = nil) -> Optional<Wrapped> {
    _valueForDevice(phone: phoneValue, pad: padValue, mac: macValue, defaultValue: defaultValue)
}

/// Returns the boolean for the current device from the values that are provided.
///
/// - Parameters:
///   - phoneValue: The boolean to use for iPhone.
///   - padValue: The boolean to use for iPad.
///   - macValue: The boolean to use for Mac.
///   - defaultValue: The default boolean to use for all other devices.
func valueForDevice(phone phoneValue: @autoclosure () -> Bool, pad padValue: @autoclosure () -> Bool, mac macValue: @autoclosure () -> Bool, defaultValue: @autoclosure () -> Bool = false) -> Bool {
    _valueForDevice(phone: phoneValue, pad: padValue, mac: macValue, defaultValue: defaultValue)
}

private func _valueForDevice<Value>(phone phoneValue: () -> Value, pad padValue: () -> Value, mac macValue: () -> Value, defaultValue: () -> Value) -> Value {
    #if os(iOS)
    valueForUIDevice(phone: phoneValue(), pad: padValue(), defaultValue: defaultValue())
    #elseif os(macOS)
    macValue()
    #endif
}

ValueForUIDevice.swift

import Foundation

/*
Put these global functions in a file that is compiled for iOS only
because they are not relevant for macOS.
*/

/// Returns the value for the current device idiom from the values that are provided.
///
/// - Parameters:
///   - phoneValue: The value to use for the iPhone idiom.
///   - padValue: The value to use for the iPad idiom.
///   - defaultValue: The default value to use for all other idioms.
func valueForUIDevice<Value>(phone phoneValue: @autoclosure () -> Value, pad padValue: @autoclosure () -> Value, defaultValue: @autoclosure () -> Value) -> Value {
    _valueForUIDevice(phone: phoneValue, pad: padValue, defaultValue: defaultValue)
}

/// Returns the value for the current device idiom from the values that are provided.
///
/// - Parameters:
///   - phoneValue: The value to use for the iPhone idiom.
///   - padValue: The value to use for the iPad idiom.
///   - defaultValue: The default value to use for all other idioms.
func valueForUIDevice<Value: Numeric>(phone phoneValue: @autoclosure () -> Value, pad padValue: @autoclosure () -> Value, defaultValue: @autoclosure () -> Value = .zero) -> Value {
    _valueForUIDevice(phone: phoneValue, pad: padValue, defaultValue: defaultValue)
}

/// Returns the value for the current device idiom from the values that are provided.
///
/// - Parameters:
///   - phoneValue: The value to use for the iPhone idiom.
///   - padValue: The value to use for the iPad idiom.
///   - defaultValue: The default value to use for all other idioms.
func valueForUIDevice<Wrapped>(phone phoneValue: @autoclosure () -> Optional<Wrapped>, pad padValue: @autoclosure () -> Optional<Wrapped>, defaultValue: @autoclosure () -> Optional<Wrapped> = nil) -> Optional<Wrapped> {
    _valueForUIDevice(phone: phoneValue, pad: padValue, defaultValue: defaultValue)
}

/// Returns the boolean for the current device idiom from the values that are provided.
///
/// - Parameters:
///   - phoneValue: The boolean to use for the iPhone idiom.
///   - padValue: The boolean to use for the iPad idiom.
///   - defaultValue: The default boolean to use for all other idioms.
func valueForUIDevice(phone phoneValue: @autoclosure () -> Bool, pad padValue: @autoclosure () -> Bool, defaultValue: @autoclosure () -> Bool = false) -> Bool {
    _valueForUIDevice(phone: phoneValue, pad: padValue, defaultValue: defaultValue)
}

private func _valueForUIDevice<Value>(phone phoneValue: () -> Value, pad padValue: () -> Value, defaultValue: () -> Value) -> Value {
    switch UIDevice.current.userInterfaceIdiom {
    case .phone:
        return phoneValue()
    case .pad:
        return padValue()
    default:
        return defaultValue()
    }
}