Swift vs. Objective-C

swift-vs-objc.md

Swift vs. Objective-C

Why Swift would be a better choice for the next production app.

Strong typing

• correctness at compile time (besides behavior)
• types as proofs (... illegal is impossible)
  • vs. testing
• Examples
  • Optional (Maybe), typed collections
• steep ramp-up, but compiles == runs well

Simpler APIs

• class declaration
• blocks/closures
• less code
  • initializers
  • string interpolation
  • (basic) operator overloading
  • literals
• no .h/.m (not really private)

Functional

• first-class primitives
• stdlib includes map, flatMap, reduce
• currying
• (most) type inference
• (somewhat) lazy

Value Types

• enums, structs
• a great complement for functional programming
• avoid state (functional core, imperative shell)
• Immutable by default, single owner
• thread safety

Faster

Current performance is in-par with C++

Look out for:

• optimization setting
• separate frameworks (with whole module optimization)
• final

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• https://realm.io/news/swift-summit-joseph-lord-performance/
• https://developer.apple.com/swift/blog/?id=27
• http://www.primatelabs.com/blog/2015/02/swift-performance-updated/

Other benefits

• namespaces
• property observers
• generics
• tuples
• operator overloading
• dynamic frameworks
  • versioned; reduced app size; can include assets etc.

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• playgrounds
• well designed from scratch (rather than a legacy system)
• developer mindshare

😱 Cons

• May have rough edges (very few post-2.0)
• Some tasks are more difficult with the strong type system (parsing JSON, building a plugin system)
• Interacting with C (lots better in 2.0)
• Familiar vs. complex
• Solutions can be too Creative ✨
• New...