@@ -8,7 +8,7 @@ import Foundation
88/// A success `Result` returning `value`
99/// This form is preferred to `Result.Success(Box(value))` because it
1010// does not require dealing with `Box()`
11- public func success< T> ( value: T ) -> Result < T > {
11+ public func success< T, E > ( value: T ) -> Result < T , E > {
1212 return . Success( Box ( value) )
1313}
1414
@@ -21,6 +21,10 @@ public func success<T>(value: T) -> Result<T> {
2121/// let fail: Result<Int> = failure()
2222///
2323
24+ /// Dictionary keys for default errors
25+ public let ErrorFileKey = " LMErrorFile "
26+ public let ErrorLineKey = " LMErrorLine "
27+
2428private func defaultError( userInfo: [ NSObject : AnyObject ] ) -> NSError {
2529 return NSError ( domain: " " , code: 0 , userInfo: userInfo)
2630}
@@ -33,35 +37,37 @@ private func defaultError(file: String = __FILE__, line: Int = __LINE__) -> NSEr
3337 return defaultError ( [ ErrorFileKey: file, ErrorLineKey: line] )
3438}
3539
36- public func failure< T> ( message: String , file: String = __FILE__, line: Int = __LINE__) -> Result < T > {
37- return failure ( defaultError ( message, file: file, line: line) )
40+ public func failure< T> ( message: String , file: String = __FILE__, line: Int = __LINE__) -> Result < T , NSError > {
41+ let userInfo : [ NSObject : AnyObject ] = [ NSLocalizedDescriptionKey: message, ErrorFileKey: file, ErrorLineKey: line]
42+ return failure ( defaultError ( userInfo) )
3843}
3944
40- public func failure< T> ( file: String = __FILE__, line: Int = __LINE__) -> Result < T > {
41- return failure ( defaultError ( file: file, line: line) )
45+ public func failure< T> ( file: String = __FILE__, line: Int = __LINE__) -> Result < T , NSError > {
46+ let userInfo : [ NSObject : AnyObject ] = [ ErrorFileKey: file, ErrorLineKey: line]
47+ return failure ( defaultError ( userInfo) )
4248}
4349
44- public func failure< T> ( error: ErrorType ) -> Result < T > {
45- return . Failure( error)
50+ public func failure< T, E > ( error: E ) -> Result < T , E > {
51+ return . Failure( Box ( error) )
4652}
4753
4854/// Construct a `Result` using a block which receives an error parameter.
4955/// Expected to return non-nil for success.
5056
51- public func try< T> ( f: NSErrorPointer -> T ? , file: String = __FILE__, line: Int = __LINE__) -> Result < T > {
57+ public func try< T> ( f: NSErrorPointer -> T ? , file: String = __FILE__, line: Int = __LINE__) -> Result < T , NSError > {
5258 var error : NSError ?
5359 return f ( & error) . map ( success) ?? failure ( error ?? defaultError ( file: file, line: line) )
5460}
5561
56- public func try( f: NSErrorPointer -> Bool , file: String = __FILE__, line: Int = __LINE__) -> Result < ( ) > {
62+ public func try( f: NSErrorPointer -> Bool , file: String = __FILE__, line: Int = __LINE__) -> Result < ( ) , NSError > {
5763 var error : NSError ?
5864 return f ( & error) ? success ( ( ) ) : failure ( error ?? defaultError ( file: file, line: line) )
5965}
6066
61- /// Container for a successful value (T) or a failure with an NSError
62- public enum Result < T> {
67+ /// Container for a successful value (T) or a failure with an E
68+ public enum Result < T, E > {
6369 case Success( Box < T > )
64- case Failure( ErrorType )
70+ case Failure( Box < E > )
6571
6672 /// The successful value as an Optional
6773 public var value : T ? {
@@ -72,10 +78,10 @@ public enum Result<T> {
7278 }
7379
7480 /// The failing error as an Optional
75- public var error : ErrorType ? {
81+ public var error : E ? {
7682 switch self {
7783 case . Success: return nil
78- case . Failure( let err) : return err
84+ case . Failure( let err) : return err. unbox
7985 }
8086 }
8187
@@ -88,7 +94,7 @@ public enum Result<T> {
8894
8995 /// Return a new result after applying a transformation to a successful value.
9096 /// Mapping a failure returns a new failure without evaluating the transform
91- public func map< U> ( transform: T -> U ) -> Result < U > {
97+ public func map< U> ( transform: T -> U ) -> Result < U , E > {
9298 switch self {
9399 case Success ( let box) :
94100 return . Success( Box ( transform ( box. unbox) ) )
@@ -99,8 +105,8 @@ public enum Result<T> {
99105
100106 /// Return a new result after applying a transformation (that itself
101107 /// returns a result) to a successful value.
102- /// Flat mapping a failure returns a new failure without evaluating the transform
103- public func flatMap< U> ( transform: T -> Result < U > ) -> Result < U > {
108+ /// Calling with a failure returns a new failure without evaluating the transform
109+ public func flatMap< U> ( transform: T -> Result < U , E > ) -> Result < U , E > {
104110 switch self {
105111 case Success ( let value) : return transform ( value. unbox)
106112 case Failure ( let error) : return . Failure( error)
@@ -114,19 +120,26 @@ extension Result: Printable {
114120 case . Success( let box) :
115121 return " Success: \( box. unbox) "
116122 case . Failure( let error) :
117- return " Failure: \( error) "
123+ return " Failure: \( error. unbox ) "
118124 }
119125 }
120126}
121127
122128/// Failure coalescing
123129/// .Success(Box(42)) ?? 0 ==> 42
124130/// .Failure(NSError()) ?? 0 ==> 0
125- public func ?? < T> ( result: Result < T > , defaultValue: @autoclosure ( ) -> T ) -> T {
131+ public func ?? < T, E > ( result: Result < T , E > , defaultValue: @autoclosure ( ) -> T ) -> T {
126132 switch result {
127133 case . Success( let value) :
128134 return value. unbox
129135 case . Failure( let error) :
130136 return defaultValue ( )
131137 }
132138}
139+
140+ /// Due to current swift limitations, we have to include this Box in Result.
141+ /// Swift cannot handle an enum with multiple associated data (A, NSError) where one is of unknown size (A)
142+ final public class Box < T> {
143+ public let unbox : T
144+ public init ( _ value: T ) { self . unbox = value }
145+ }
0 commit comments