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Created May 13, 2015

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Swift: David's Top 10 "Do This" List
David's Top 10: Do That When Writing Swift
1) Purchase Dash (OS X and iOS) and get Swift from SwiftDoc.org (invaluable reference, I use it daily!)
2) Use Enums for UIView tags and SegmentedControl segments;
enum MyViews: Int { case OKButton=1...} then switch MyViews(rawValue: view.tag)
also for states (somewhat replaces C's X-Macros, helps during debugging)
enum State: String { case Idle = "Idle" ...} ;
let s: State = State(rawValue: "Idle")!; println("\(s.rawValue)") // Idle
3) When objects need configuration, you can use closures:
lazy var object: Foo = { let foo=Foo(delegate: self); foo.x = "y"; return foo;} ()
Benefit: moves "hidden" initializer code in viewDidLoad/etc to top of class.
4) Add main and after to your Code Snippets - big time saver if you use them often:
main:
dispatch_async(dispatch_get_main_queue()) { /* new line */ }
after:
let t = dispatch_time(DISPATCH_TIME_NOW, Int64(250 * NSEC_PER_MSEC))
dispatch_after(t, dispatch_get_main_queue()) { /* new line */ }
5) Use same variable name with optional unwrapping (a 'best practice'): if let user = user {...
6) Use "#if true" and "if true" to your advantage. Former to enable/disable chunks of code (but leave them readable),
the latter replaces C's "{...}" scoping blocks.
7) Switches are syntactic sugar for a list of if and else if statements - most probable should be first in performance
sensitive code. Long cases with a often hit default case can be a problem (C often uses jump tables for switches).
8) Never forget: Arrays, Dictionaries, and Sets are all values! If changing a structure in an array,
get it, change it, write it back.
9) Use the extended if let style (from Nate Cook, NSHipster), new in Swift 1.2:
if let
a = b where yada yada,
c = d where blah blah // can prefix 'let if you really want to
{ // each clause must be unwrapping an optional with no general logic allowed except in the where section
10) Add a 'nullability' Code Snippet - then use it in your older Objective C code
#if __has_feature(nullability)
NS_ASSUME_NONNULL_BEGIN
#else
// For Object pointers
#define nullable
#define nonnull
// For C pointers
#define __nullable
#define __nonnull
#endif
#if __has_feature(nullability)
NS_ASSUME_NONNULL_END
#endif
Bonus read: Erica Sadun's "Don't do list" http://ericasadun.com/2015/05/05/swift-dont-do-that/
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