Hands-On Design Patterns with Swift

Implementing NSCopying automatically

Let's create an AutoCopy.stencil protocol, so that Article copy implementation can be generated using Sourcery:

{% for type in types.implementing.AutoCopy %}extension {{ type.name }}: NSCopying {    func copy(with zone: NSZone? = nil) -> Any {        return {{type.name}}(        {% map type.variables into vars using var %}            {{ var.name }}: {{ var.name }}{% endmap %}        {{ vars|join:"," }})    }}{% endfor %}

It will generate the following AutoCopy.generated.swift:

extension Article: NSCopying {    func copy(with zone: NSZone? = nil) -> Any {        return Article(            id: id,            title: title,            contents: contents,            author: author,            date: date,            views: views)    }}

As you may have noticed, this is a simple implementation where the array's contents are ...