Number 36

Converter.swift

import Foundation

class Converter {
    static let queryString = "http://www.freecurrencyconverterapi.com/api/v3/convert?q="
    static let requestQueue = NSOperationQueue()
    
    static func convertFrom(from:String, to:String, amount:Double, callback:(Double) -> Void) {
        let query = "\(from)_\(to)"
        let q = queryString + "\(query)&compact=y"
        let req = NSURLRequest(URL: NSURL(string: q)!)
        
        NSURLConnection.sendAsynchronousRequest(req, queue: requestQueue) {res, data, err in
            if err != nil {
                println(err)
                return
            }
            
            var err:NSError?
            
            if let json = NSJSONSerialization.JSONObjectWithData(data,
                options: NSJSONReadingOptions.AllowFragments, error: &err) as? NSDictionary {
                    let value = (json[query] as! NSDictionary)["val"] as! Double
                    
                    callback(amount * value)
            }
        }
    }
}

main.swift

import Foundation

var from = "USD"
var to = ""
var amount = 0.00

for var i = 0; i < Process.arguments.count; i++ {
    if Process.arguments[i] == "-to" {
       to = Process.arguments[i + 1].uppercaseString
    } else if Process.arguments[i] == "-from" {
        from = Process.arguments[i + 1].uppercaseString
    } else {
        let a = (Process.arguments[i] as NSString).doubleValue
        
        if a != 0 {
            amount = a
        }
    }
}

if to == "" {
    println("-to cannot be omitted")
}

Converter.convertFrom(from, to: to, amount: amount) {value in
    println(value)
    exit(0)
}

CFRunLoopRun()