目的是为了看到Swift项目中的以下代码：
private extension IndexPath {
static let configSection = 0
static let provisionersSection = 1
static let networkKeysSection = 2
static let optionsSection = 3
static let numberOfSections = optionsSection + 1
static let configurationTitles = [
"Export Everything"
]
static let detailsTitles = [
"Export Device Keys"
]
}
private extension IndexSet {
static let all = IndexSet(integersIn: 1..<IndexPath.numberOfSections)
static let config = IndexSet([IndexPath.configSection])
static let provisioners = IndexSet([IndexPath.provisionersSection])
static let networkKeys = IndexSet([IndexPath.networkKeysSection])
static let options = IndexSet([IndexPath.optionsSection])
}
参考文章：
【http://t.zoukankan.com/yuqingzhude-p-4844897.html】
标签：IndexSet,optionsSection,private,static,let,Swift From： https://www.cnblogs.com/cchHers/p/17015816.html