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Swift High Performance

You're reading from   Swift High Performance Leverage Swift and enhance your code to take your applications to the next level

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Product type Paperback
Published in Nov 2015
Publisher Packt
ISBN-13 9781785282201
Length 212 pages
Edition 1st Edition
Languages
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Author (1):
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Kostiantyn Koval Kostiantyn Koval
Author Profile Icon Kostiantyn Koval
Kostiantyn Koval
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Table of Contents (10) Chapters Close

Preface 1. Exploring Swift's Power and Performance FREE CHAPTER 2. Making a Good Application Architecture in Swift 3. Testing and Identifying Slow Code with the Swift Toolkit 4. Improving Code Performance 5. Choosing the Correct Data Structure 6. Architecting Applications for High Performance 7. The Importance of Being Lazy 8. Discovering All the Underlying Swift Power Index

REPL in Xcode


One of the more interesting functionalities available in the Xcode LLDB console is that you can run Swift REPL there. You can enter and execute Swift code when you stop the application execution in the debugger. This is very useful for debugging purposes.

Note

REPL can only access public types, functions, and public global variables. Local variables are not visible in REPL. If you need to work with local variables, use LLDB commands instead.

To enter an REPL console, we first have to stop the program execution and enter the LLDB debugger. There are three commands for interacting with REPL:

  • Enter REPL: repl

  • Exit REPL: :

  • Execute the LLDB command in REPL: : command, for example, :p name

We can execute the same function as before, but now use REPL commands in the debug console, as shown here:

Now let's look at more interesting use cases of REPL. When you enter REPL, you can enter and execute Swift code. You also have access to publicly declared Swift code in your application in...

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