Swift Code Reuse Made Simple

What is the difference between static and dynamic libraries? Between libraries and frameworks? Between libraries and modules? How to manage the code by splitting it reusable chunks?
These and some other questions are answered in this presentation.

Presented at SwiftHeroes 2019 in Italy, Turin, on 15th of November.

Transcript

1. Swift code reuse
   made simple
   modules, packages, libraries
   

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2. @aronskaya
   • macOS Engineer at MacPaw
   • CleanMyMac
   

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3. Hoover
   

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4. Fixel
   

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5. @aronskaya
   • macOS Chapter Lead at
   Women Who Code Kyiv
   • workshop mentor at SwiftAveiro
   • one of founders of MacPaw Tech Talks
   

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6. Swift code reuse
   made simple
   modules, packages, libraries
   

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8. Behind this
   talk
   1⃣ projects with 1 target
   

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9. Behind this
   talk
   1⃣
   
   projects with 1 target
   apps, containing several apps
   

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10. Behid this
    talk
    1⃣
    
    
    projects with 1 target
    apps, containing several apps
    C++ libraries, shared with Linux
    

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11. Behid this
    talk
    1⃣
    
    
    
    projects with 1 target
    apps, containing several apps
    C++ libraries, shared with Linux
    projects with dozens internal libs
    

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12. 1 app == 27 projects
    up to 14 targets per project
    

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13. Agenda
    ⁉ Why separate codebase
    

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14. Agenda
    ⁉ Why separate codebase
    How to do it: static, dylibs, frameworks, modules
    

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15. Agenda
    ⁉ Why separate codebase
    How to do it: static, dylibs, frameworks, modules
    Dependency management: CocoaPods, Swift Package Manager
    

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16. Agenda
    ⁉ Why separate codebase
    How to do it: static, dylibs, frameworks, modules
    Takeaways: best practices & modern approach
    Dependency management: CocoaPods, Swift Package Manager
    

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17. Why
    

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21. Faster
    compilation
    

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22. Faster
    app launch
    

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23. Smaller
    app bundle
    

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24. ⌚ Easily
    support new
    platforms
    

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25. Grow
    your GitHub
    

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26. Test once
    use again and again
    

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27. Learn&Train
    to think bigger
    

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28. How Apple does it
    

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29. How Apple does it
    

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30. How Apple does it
    172
    

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31. Programmer evolution
    

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32. Programmer evolution
    it works!
    
    

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33. Programmer evolution
    it works!
    
    it works & is grouped in classes
    
    
    

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34. Programmer evolution
    it works!
    
    it works & is grouped in classes
    it works & is grouped in reusable classes
    
    
    
    
    

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35. Programmer evolution
    it works!
    
    it works & is grouped in classes
    it works & is grouped in reusable classes
    it works & grouped in a reusable module
    
    
    
    
    
    
    
    
    

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36. The Versus
    Quiz
    

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37. Static
    Dynamic
    

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38. Static
    linking / libraries
    

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39. Static library
    

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40. Amazing Notes app
    

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41. Amazing Notes app
    

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43. Dynamic
    linking / libraries
    

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44. Dynamic library
    dylib
    

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45. Library
    Framework
    

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49. Library
    Conceptually Technically
    ❌ doesn't affect the lifecycle of
    our app or objects
    1⃣ a file (+ header files)
    can be dynamic or static
    Conceptual examples:
    CocoaLumberjack, SDWebImage,
    AFNetworking
    Technical example: stdlib
    
    

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50. dylib
    

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51. Framework
    Conceptually Technically
    ↺ affects the lifecycle of our app or
    objects
    a directory with at least 1 dylib
    is basically a dylib with bells &
    whistles
    Example: UIKit (we build our logic based on delegate callbacks—
    SceneDelegate, AppDelegate, UITableViewDelegate
    

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53. Recap
    Static library
    headers + code, embedded into client's
    executable
    Dynamic library headers + code in a separate file
    Framework dynamic library + resources
    

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54. Library
    Module
    

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55. –Access Control—The Swift Programming Language docs
    “A module is a single unit of code distribution—a
    framework or application that is built and shipped as a
    single unit and that can be imported by another
    module with Swift’s import keyword.”
    

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56. –Access Control—The Swift Programming Language docs
    “A module is a single unit of code distribution—a
    framework or application that is built and shipped as a
    single unit and that can be imported by another
    module with Swift’s import keyword.”
    

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57. Module
    is just another type of header
    

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58. ❌Implementation
    

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59. ❌Implementation
    The impl lives
    in a static or a dynamic library
    

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60. 2 Types of Modules
    

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61. 2 Types of Modules
    Clang module
    •Objective-C, Swift…
    •module.modulemap
    

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62. 2 Types of Modules
    Clang module Swift module
    •Objective-C, Swift
    •module.modulemap
    •Swift only
    •.swiftdoc, .swiftmodule
    

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63. Swift Package Manager
    CocoaPods
    

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64. SPM vs CocoaPods
    Swift ✅
    Objective-C
    Xcode integration
    Multi platform support
    Resources
    

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65. SPM vs CocoaPods
    Swift ✅ ✅
    Objective-C
    Xcode integration
    Multi platform support
    Resources
    

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66. SPM vs CocoaPods
    Swift ✅ ✅
    Objective-C ✅
    Xcode integration
    Multi platform support
    Resources
    

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67. SPM vs CocoaPods
    Swift ✅ ✅
    Objective-C ✅ ⏳
    Xcode integration
    Multi platform support
    Resources
    

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68. SPM vs CocoaPods
    Swift ✅ ✅
    Objective-C ✅ ⏳
    Xcode integration ❌
    Multi platform support
    Resources
    

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69. SPM vs CocoaPods
    Swift ✅ ✅
    Objective-C ✅ ⏳
    Xcode integration ❌ ✅
    Multi platform support
    Resources
    

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70. SPM vs CocoaPods
    Swift ✅ ✅
    Objective-C ✅ ⏳
    Xcode integration ❌ ✅
    Multi platform support ❌
    Resources
    

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71. SPM vs CocoaPods
    Swift ✅ ✅
    Objective-C ✅ ⏳
    Xcode integration ❌ ✅
    Multi platform support ❌ ✅
    Resources
    

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72. SPM vs CocoaPods
    Swift ✅ ✅
    Objective-C ✅ ⏳
    Xcode integration ❌ ✅
    Multi platform support ❌ ✅
    Resources ✅
    

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73. SPM vs CocoaPods
    Swift ✅ ✅
    Objective-C ✅ ⏳
    Xcode integration ❌ ✅
    Multi platform support ❌ ✅
    Resources ✅ ⏳
    

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75. –Serg Krivoblotsky, my college
    “I think, SPM is the most convenient Dependency
    Manager on the market. And Xcode integration makes
    it a dream. You paste a GitHub link—and you're in
    game!”
    

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76. –Serg Krivoblotsky, my college
    “I think, SPM is the most convenient Dependency
    Manager on the market. And Xcode integration makes
    it a dream. You paste a GitHub link—and you're in
    game!”
    
    

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82. Takeaways
    

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83. Code Reuse Evolution
    ⭐ Static libs →
    

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84. Code Reuse Evolution
    ⭐ Static libs →
    ⭐⭐ Dynamic libs →
    

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85. Code Reuse Evolution
    ⭐ Static libs →
    ⭐⭐ Dynamic libs →
    ⭐⭐⭐ Frameworks, Modules →
    

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86. Code Reuse Evolution
    ⭐ Static libs →
    ⭐⭐ Dynamic libs →
    ⭐⭐⭐ Frameworks, Modules →
    ⭐⭐⭐⭐ Swift Packages
    

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87. Triggers: when separate code
    

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88. Triggers: when separate code
    1. You have files included in
    several targets
    

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89. Triggers: when separate code
    1. You have files included in
    several targets
    2. You have a group of classes,
    that work together to provide a
    single piece of functionality
    

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90. What to put in a separate lib?
    •Networking logic
    

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91. What to put in a separate lib?
    •Networking logic
    •Foundation enhancements
    

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92. What to put in a separate lib?
    •Networking logic
    •Foundation enhancements
    •Trial limitations
    

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93. What to put in a separate lib?
    •Networking logic
    •Foundation enhancements
    •Trial limitations
    •Working with database
    

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94. What to put in a separate lib?
    •Networking logic
    •Foundation enhancements
    •Trial limitations
    •Working with database
    • Analytics
    

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95. What to put in a separate lib?
    •Networking logic
    •Foundation enhancements
    •Trial limitations
    •Working with database
    • Analytics
    •Every new feature
    

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96. It is to have
    a library per
    each feature
    

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97. It is to have
    a library per
    each feature
    Not 70
    

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98. Tips on designing an interface
    • Allow flexible configuration (pass it in parameters, don’t
    try to guess what the client wants)
    init(param1:param2:param3:param4:)
    

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99. Tips on designing an interface
    • Allow also simple default setup (have little or no
    parameters)
    init()
    

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100. Tips on designing an interface
     • Allow asynchronous execution
     func execute(param0:param1:completionHandler:)
     

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101. Tips on designing an interface
     • Use Apple Frameworks as example
     func tableView(_ tableView: UITableView,
     didDeselectRowAt indexPath: IndexPath)
     

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102. Tips on designing an interface
     • Use famous and popular libraries and frameworks as examples
     

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103. What to use
     if I start a project today?
     

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104. What to use
     if I start a project today?
     Frameworks
     

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105. What to use
     if I start a project today?
     Swift Package Manager
     

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106. Thank you!
     iaronskaya
     Q&A
     

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