0.1 Basics

Compatibility

• 95%+ devices are on iOS 10/11
• iOS 10+ only requires 2x and 3x images (no need to include 1x images)

REPL – Read Evaluate Print Loop

• command line input for quick testing
• open terminal:
• sudo xcode-select -s /Applications/Xcode.app/Contents/Developer
• xcrun swift

Naming Style Guide

• use camel case
• Class names are capitalized
• don’t use all caps nor _’s
• name parameters for functions/inits
• spaces matter → do not put numbers right next to operation stmts
• (ie. i>=4 should be i >= 4)

Playground

• not attached to a file
  
• more of a scratch pad for testing
  
• cannot be used to test memory management

Scope

• can access variables only in the portion of the program in which they are declared
  
• can be limited to:  if stmts, for loops, functions, classes, global
  
• global is the default if declared in an area that isn’t scoped

Data Types

Named

• type that can be given a particular name when it is defined
  
• includes arrays, dictionaries, optionals, classes, structures, enumerations, and protocols

Compound

• type without a name, defined in the Swift language itself
  
• includes tuples, closures, & functions

Declaration

var – used to create a variable
let – used to create a constant

• use let whenever possible → performance improvements (fixed memory size)
• when the type is obvious, let Swift infer it
• types cannot be changed once set