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| // This code accompanies a blog post: http://chris.eidhof.nl/posts/json-parsing-in-swift.html | |
| // | |
| // As of Beta5, the >>= operator is already defined, so I changed it to >>>= | |
| import Foundation | |
| let parsedJSON : [String:AnyObject] = [ | |
| "stat": "ok", | |
| "blogs": [ | |
| "blog": [ | |
| [ | |
| "id" : 73, | |
| "name" : "Bloxus test", | |
| "needspassword" : true, | |
| "url" : "http://remote.bloxus.com/" | |
| ], | |
| [ | |
| "id" : 74, | |
| "name" : "Manila Test", | |
| "needspassword" : false, | |
| "url" : "http://flickrtest1.userland.com/" | |
| ] | |
| ] | |
| ] | |
| ] | |
| struct Blog { | |
| let id: Int | |
| let name: String | |
| let needsPassword : Bool | |
| let url: NSURL | |
| } | |
| func parseBlog(blog: AnyObject) -> Blog? { | |
| let mkBlog = curry {id, name, needsPassword, url in Blog(id: id, name: name, needsPassword: needsPassword, url: url) } | |
| return asDict(blog) >>>= { | |
| mkBlog <*> int($0,"id") | |
| <*> string($0,"name") | |
| <*> bool($0,"needspassword") | |
| <*> (string($0, "url") >>>= toURL) | |
| } | |
| } | |
| func parseJSON() { | |
| let blogs = dictionary(parsedJSON, "blogs") >>>= { | |
| array($0, "blog") >>>= { | |
| join($0.map(parseBlog)) | |
| } | |
| } | |
| println("posts: \(blogs)") | |
| } | |
| extension Blog : Printable { | |
| var description : String { | |
| return "Blog { id = \(id), name = \(name), needsPassword = \(needsPassword), url = \(url)" | |
| } | |
| } | |
| func toURL(urlString: String) -> NSURL { | |
| return NSURL(string: urlString) | |
| } | |
| func asDict(x: AnyObject) -> [String:AnyObject]? { | |
| return x as? [String:AnyObject] | |
| } | |
| func join<A>(elements: [A?]) -> [A]? { | |
| var result : [A] = [] | |
| for element in elements { | |
| if let x = element { | |
| result += [x] | |
| } else { | |
| return nil | |
| } | |
| } | |
| return result | |
| } | |
| infix operator <*> { associativity left precedence 150 } | |
| func <*><A, B>(l: (A -> B)?, r: A?) -> B? { | |
| if let l1 = l { | |
| if let r1 = r { | |
| return l1(r1) | |
| } | |
| } | |
| return nil | |
| } | |
| func flatten<A>(x: A??) -> A? { | |
| if let y = x { return y } | |
| return nil | |
| } | |
| func array(input: [String:AnyObject], key: String) -> [AnyObject]? { | |
| let maybeAny : AnyObject? = input[key] | |
| return maybeAny >>>= { $0 as? [AnyObject] } | |
| } | |
| func dictionary(input: [String:AnyObject], key: String) -> [String:AnyObject]? { | |
| return input[key] >>>= { $0 as? [String:AnyObject] } | |
| } | |
| func string(input: [String:AnyObject], key: String) -> String? { | |
| return input[key] >>>= { $0 as? String } | |
| } | |
| func number(input: [NSObject:AnyObject], key: String) -> NSNumber? { | |
| return input[key] >>>= { $0 as? NSNumber } | |
| } | |
| func int(input: [NSObject:AnyObject], key: String) -> Int? { | |
| return number(input,key).map { $0.integerValue } | |
| } | |
| func bool(input: [NSObject:AnyObject], key: String) -> Bool? { | |
| return number(input,key).map { $0.boolValue } | |
| } | |
| func curry<A,B,R>(f: (A,B) -> R) -> A -> B -> R { | |
| return { a in { b in f(a,b) } } | |
| } | |
| func curry<A,B,C,R>(f: (A,B,C) -> R) -> A -> B -> C -> R { | |
| return { a in { b in {c in f(a,b,c) } } } | |
| } | |
| func curry<A,B,C,D,R>(f: (A,B,C,D) -> R) -> A -> B -> C -> D -> R { | |
| return { a in { b in { c in { d in f(a,b,c,d) } } } } | |
| } | |
| infix operator >>>= {} | |
| func >>>= <A,B> (optional : A?, f : A -> B?) -> B? { | |
| return flatten(optional.map(f)) | |
| } |
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