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Mastering Swift 3 - Linux

You're reading from   Mastering Swift 3 - Linux Learn to build fast and robust applications on the Linux platform with Swift

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Product type Paperback
Published in Jan 2017
Publisher Packt
ISBN-13 9781786461414
Length 380 pages
Edition 1st Edition
Languages
Tools
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Author (1):
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Jon Hoffman Jon Hoffman
Author Profile Icon Jon Hoffman
Jon Hoffman
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Table of Contents (24) Chapters Close

Mastering Swift 3 - Linux
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
1. Taking the First Steps with Swift FREE CHAPTER 2. Learning About Variables, Constants, Strings, and Operators 3. Using Swift Collections and the Tuple Type 4. Control Flow and Functions 5. Classes and Structures 6. Using Protocols and Protocol Extensions 7. Protocol-Oriented Design 8. Writing Safer Code with Error Handling 9. Custom Subscripting 10. Using Optional Types 11. Working with Generics 12. Working with Closures 13. Using C Libraries with Swift 14. Concurrency and Parallelism in Swift 15. Swifts Core Libraries 16. Swift on Single Board Computers 17. Swift Formatting and Style Guide 18. Adopting Design Patterns in Swift

Swift and the Swift REPL


There are a couple of ways in which you can quickly experiment with Swift code. The first is the Swift interactive Read Evaluate Print Loop (REPL). The REPL is a command line tool that evaluates our code as we write it. Developers who are used to interpreting languages will be comfortable using this tool.

To start the REPL, you will need to open a terminal prompt and enter the following command:

swift

You will be greeted with a prompt similar to the following:

Welcome to Swift version 3.0 ({your-swift-version}). Type :help for
    assistance
1>

From here, we can type in any Swift statement and hit Enter. The REPL will immediately execute our code. The following is an example:

1>  var x = 10
x: Int = 10
2>  x += 5
3>  print(x)
15

To exit the REPL, type the following command:

:quit

We can also quickly test a Swift source file using the swift command. To try this out, create a file named Hello.swift, and put the following code in it:

print("Hello") 

Now let's run the following command to execute this source file:

swift Hello.swift 

You should see the message Hello printed to the console. The REPL and Swift commands are extremely powerful tools, and you can do a lot more than just prototyping new code. If you find these tools useful, I would recommend spending time learning about the various advanced features.

You have been reading a chapter from
Mastering Swift 3 - Linux
Published in: Jan 2017
Publisher: Packt
ISBN-13: 9781786461414
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