Language Reference

Language Reference

1.关键字

Keywords used in declarations: class, deinit, enum, extension, func, import, init, internal, let, operator, private, protocol, public, static, struct, subscript, typealias, and var.

Keywords used in statements: break, case, continue, default, do, else, fallthrough, for, if, in, return, switch, where, and while.

Keywords used in expressions and types: as, dynamicType, false, is, nil, self, Self, super, true, __COLUMN__, __FILE__, __FUNCTION__, and __LINE__.

Keywords reserved in particular contexts: associativity, convenience, dynamic, didSet, final, get, infix, inout, lazy, left, mutating, none, nonmutating, optional, override, postfix, precedence, prefix, Protocol, required, right, set, Type, unowned, weak and willSet. Outside the context in which they appear in the grammar, they can be used as identifiers.

2.Declaration

swift中的定义和声明是一体的。声明即定义。

3.Attributes

@assignment 重载混合赋值运算符

@class_protocol 限制协议只允许类继承

@noreturn 放置在函数，类中的方法的前面表示该函数没有返回值

@NSCopying

@NSManaged

@objc 声明该类型可以用于Objective－C，比如非嵌套类，协议，属性，方法等

@UIApplicationMain 放在类前面，代表该类是app的代理。