我正在使用Alamofire,我使用枚举来描述我在自述文件中建议使用的API。
端点表示如下: p>
public enum API { case GetStops(stopCode:String?) case GetPhysicalStops case GetLinesColors case GetNextDepartures(stopCode:String,departureCode:String?,linesCode:String?,destinationCode:String?)}可选参数是互斥的:
public var URLRequest:NSMutableURLRequest { let result((path:String,参数:[String:AnyObject]?)= { switch self { case .GetStops(let stopCode)where stopCode!= nil: return(GetStops.json,[stopCode:stopCode!]) case .GetStops(_): return(GetStops.json,nil) case。 GetPhysicalStops:返回(GetPhysicalStops.json,nil) case .GetLinesColors: return(GetLinesColors,nil) case .GetNextDepartures(let stopCode,let departCode,_,_)where departureCode! = nil: return(GetNextDepartures,[stopCode:stopCode,departureCode:departureCode!]) case .GetNextDepartures(let stopCode,_,let linesCode,_)where linesCode!= nil: return(GetNextDepartures,[stopCode:stopCode,linesCode:linesCode!]) case .GetNextDepartures(let stopCode,_,_,let destinationsCode)where destinationsCode!= nil : return(GetNextDepartures,[stopCode:stopCode,destinationsCode:destinationsCode!]) case .GetNextDepartures(let stopCode,_,_,_): return GetNextDepartures,[stopCode:stopCode])} }()有没有办法解开一个在这个语句中,可选的包含(如 if let ),并避免在此语句中显式展开:
case .GetStops(let stopCode)where stopCode!= nil: return(GetStops.json,[stopCode:stopCode!])解决方案
您可以使用 .Some(x) pattern( .some(x)):
case .GetStops(let .Some(stopCode)): return(GetStops.json,[stopCode:stopCode])从Swift 2(Xcode 7)开始,这可以简写为 x? pattern:
case .GetStops(let stopCode?): return(GetStops.json,[stopCode:stopCode])相关值被测试为非零和解包(类似于可选绑定)。 / p>
I'm currently using Alamofire and I use an enum to describe the API I used as advised in the readme.
The endpoints are represented as follows:
public enum API { case GetStops(stopCode:String?) case GetPhysicalStops case GetLinesColors case GetNextDepartures(stopCode:String, departureCode:String?, linesCode:String?, destinationsCode:String?) }The optional parameters are mutually exclusive:
public var URLRequest: NSMutableURLRequest { let result:(path:String, parameters:[String:AnyObject]?) = { switch self { case .GetStops(let stopCode) where stopCode != nil : return ("GetStops.json", ["stopCode" : stopCode!]) case .GetStops(_): return ("GetStops.json", nil) case .GetPhysicalStops: return ("GetPhysicalStops.json", nil) case .GetLinesColors: return ("GetLinesColors",nil) case .GetNextDepartures(let stopCode, let departureCode, _, _) where departureCode != nil: return ("GetNextDepartures", ["stopCode" : stopCode, "departureCode": departureCode!]) case .GetNextDepartures(let stopCode, _, let linesCode, _) where linesCode != nil: return ("GetNextDepartures", ["stopCode" : stopCode, "linesCode": linesCode!]) case .GetNextDepartures(let stopCode, _, _, let destinationsCode) where destinationsCode != nil: return ("GetNextDepartures", ["stopCode" : stopCode, "destinationsCode": destinationsCode!]) case .GetNextDepartures(let stopCode,_,_,_): return ("GetNextDepartures",["stopCode":stopCode]) } }()Is there a way to unwrap automatically the optional contained (like if let) within the tuple and avoiding to explicity unwrap like in this statement :
case .GetStops(let stopCode) where stopCode != nil : return ("GetStops.json", ["stopCode" : stopCode!])解决方案
You can use the .Some(x) pattern (.some(x) in Swift 3):
case .GetStops(let .Some(stopCode)): return ("GetStops.json", ["stopCode" : stopCode])As of Swift 2 (Xcode 7), this can be shorter written as x? pattern:
case .GetStops(let stopCode?): return ("GetStops.json", ["stopCode" : stopCode])The associated value is tested to be non-nil and unwrapped (similar as in an optional binding).
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