Compact summary of swift
This is not intended to be the complete language.

Available on MAC OSX and Linux

name your file         xxx.swift

execute your file      swift xxx.swift

execute your file and save output in a file with optional arguments
                       swift xxx.swift arg1 arg2 > xxx.out

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

Keywords used in statements:
  break, case, continue, default, defer, do, else, fallthrough, for, guard,
  if, in, repeat, return, switch, where, while, override

Keywords used in expressions and types:
  as, Any, catch, false, is, nil, rethrows, super, self, Self, throw,
  throws, true, try

Keywords used for types:
  Array, Int, Double, Float, Bool, Character, String, class, dictionary,
  repeating, count, Int8, Int16, Int32, ...

Operators:
+ - * / ++ -- += -= *= /= %
== < <= > >= === ??

The first, smallest, complete program:

// hello_world.swift    // starts a comment,  two lines, a complete program
print("Hello, world!")

If you are programming swift to run on both MAC OSX and Linux, get libraries:

#if os(OSX) || os(iOS) // complete portable program
import Foundation
#elseif os(Linux)
import Glibc
#endif// 
print("sin(1.0)=\(sin(1.0))") //  \( ) can have any variable or function